RK Radial Keratotomy ? ALK? PRK Photorefractive Keratectomy ? LASIK Laser Assisted In Situ Keratomileusis ? ICR/ICS (Intacs)? ICL? Time To Get Informed.
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PRK Eye IconEyeKnowWhy Site Highlights PRK Eye Icon

Site Purpose Refractive Surgery Defined Assessing Information Sources Eye Structure - Overview and Links
The Diopters Cornea Clarifying Important Concepts Snellen Testing
Refractive Surgery and Loss of Vision Acuity How The Cornea Heals Patient Happiness and Unhappiness FDA
Refractive Surgery History 'Modern' RK and PERK Results PRK and LASIK Refractive Surgery Hype and Euphemisms
Refractive Surgery Complications (List and Summary) Experience Effects Without Surgery Rationalizations Informed Consent
Employer Positions on PRK/LASIK Reporting Complications Employee Educ. Package Future Impact
Non Surgical Treatments Other Web Sites of Interest Q & A Your Own Conclusions

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What This Site Is About

What is 'vision correction surgery'? Does a patient's statement that they no longer wear glasses mean they have excellent or perfect vision? What does 20/20 really mean? What does "safe" and "effective" really mean? It's time to become an informed consumer. This site presents a detailed view of refractive surgery, and covers extensively the refractive surgery industry that markets refractive surgery procedures such as RK (Radial Keratotomy), PRK (Photorefractive Keratectomy), LASIK (Laser assisted In-situ Keratomileusis)and many other procedures collectively known as vision 'correction' surgery to the public. EyeKnowWhy uses the term Refractive Surgery throughout this site to refer to all 'correction' surgeries. Whenever you see a word in single quotes ('), think "For lack of a better word" or "euphemism". These are EyeKnowWhy opinions and everyone is free to disagree. References have been provided for your own research.

But keep a few quotes in mind as you evaluate this site, as well as the statements and conclusions of other sites and references you encounter on the web and at your public and medical school library.:

"Everybody has an opinion, this is just one." EyeKnowWhy, 1997.

"You can call it haze, trace, clouding, or insignificant, but it's still a scar." EyeKnowWhy, 1997

"Complications may be rare, but if it happens to you, the chances are 100%." Dr. Walter Stark, Johns Hopkins Medical School, as quoted in Consumer Reports, Feb. 1994, "Surgery Instead of Glasses?"

"When you burn a silicon wafer with the excimer laser and the etching doesn't turn out right, you can throw it away and start over. You can't do that with a cornea." EyeKnowWhy, 1997

"It's the same each time with progress. First they ignore you, then they say you're mad, then dangerous, then there's a pause and then you can't find anyone who disagrees with you." - Tony Benn (b. 1925), British Labour politician. Quoted in: Observer (London, 6 Oct. 1991).

You are welcome to excerpt any length of this web site and distribute it freely to whomever you choose provided it is for non-profit purposes only. You should identify the source as Website: http://members.aol.com/eyeknowwhy/ Site Title: I Know Why Refractive Surgeons Wear Glasses.

What This Site Does Not Extensively Cover At This Time

This site does not discuss the following extensively at this time:

Who is EyeKnowWhy?

EyeKnowWhy is a consumer health site created to present a more accurate picture of refractive surgery. We are not ophthalmologists or optometrists or sponsored or paid by them. We are a group of concerned citizens speaking out based on our research. You can consider this site questionable and go on your way or read it and assess its validity yourself. We do know individuals who have had refractive surgery, some with excellent outcomes and some with devastating outcomes.

EyeKnowWhy bases this site on extensive research, much of it unavailable on the web. EyeKnowWhy recommends you do your own research and form your own opinions. There's nothing for sale here! No agenda to stop refractive surgery. Refractive surgery is a 'miracle' for many people, but not everyone. Be suspicious of everyone - EyeKnowWhy and prestigious surgeons and acclaimed refractive surgery researchers included. That's the way a free market, free speech, caveat emptor ('buyer beware') democratic society works. If you have already had refractive surgery, THINK NOW before you go further - Do I want to know more? This site is graphic and presents issues that may disturb postoperative patients. If not, exit this web site now.

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What Is Refractive Surgery?

Refractive surgery refers to a range of surgical procedures using knives, lasers, or some combination to wound and alter the cornea resulting in structural changes in the cornea's curvature. The resultant change in the cornea's shape often produces a significant change in its refractive power (and thus the eye's visual perception) that may be perceived as desirable by many patients. Damaging the cornea structure creates an array of vision and ocular side effects, some temporary and some permanent. The results of refractive surgery are irreversible and controversial and should only be considered after thorough research.

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Book Turn GIF Assessing Information Sources

How do you get accurate and unbiased information about refractive surgery procedures like PRK and LASIK? Everybody has an agenda. Who do you believe? Is anything you see, hear or read believable or accurate? Your sources for information about refractive surgery are advertisements and 'patient information' literature from refractive surgery clinics, discussions with people who have undergone refractive surgery (known as postops), consumer books on refractive surgery, web sites with varying agendas, believability and depth, web 'vision discussion' newsgroups, discussions with your optometrists, 'PRK and LASIK vision correction education seminars', ophthalmology trade journals and magazines, medical associations, ophthalmology medical journals of varying quality, TV news and magazine shows and lay press (magazines and newspaper) articles on refractive surgery. All (including this site) should be reviewed with healthy skepticism. EyeKnowWhy provides an extended discussion of Refractive Surgery Information Sources - Extended Discussion and is recommended for first time visitors.

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The Eye Structure - Overview and Links

Eye Anatomy OverviewThe eye is a complex structure, and EyeKnowWhy recommends you visit other sites (and especially your public library) to get a general overview of the eye's structure, myopia, hyperopia, astigmatism, and presbyopia. There are hundreds of eye sites that discuss (with variable depth and accuracy) the eye and refractive disorders. Most of the web sites lack depth but they are a start. You can use any search engine and keywords like "Photorefractive Keratectomy", "PRK", "LASIK", or "informed consent", or any combination. Some miscellaneous web sites of note are listed toward the end of this document (see site highlights).

The American Academy of Ophthalmology is one of numerous web sites you should visit before continuing further.

American Academy of Ophthalmology - Refractive Surgery

American Academy of Ophthalmology - Home Page

Some sites provide a comprehensive set of ophthalmology listings. Check out Eye Resources on the Net for their link list.

As mentioned at Eyenet and other sites and the books obtained from your library, light goes through six optical mediums before the image is processed by the brain.

They are:

Sight is extremely complex, and all parts of the eye must operate optimally to provide the best possible vision. Unfortunately, the eye is so complex, that slight variations can cause unusual and disturbing vision problems. The most common problems are the refractive errors nearsightedness, farsightedness, and astigmatism and are generally correctable by glasses or contacts. Correction with eyeglasses or contacts may not be easily accomplished in severe myopia, hyperopia and astigmatism. Refractive errors are defined using a measurement called diopters.

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The Diopters

Refractive errors are measured in diopters. The range is between +15 and 0 (hyperopic) and 0 and -25 (myopic), with the range +6 to -6 being by far the most common subset encompassing over 96% of refractive errors. Plus (+) diopters (for correcting hyperopia) indicate a convex lens (bows outward) is needed in eyeglasses or contacts to 'increase the bend' of light rays before they enter the eye. As you recall from the above sites, in hyperopic eyes, the focused image is 'beyond' the retina. The convex lens bends the light so that the cornea and lens can successfully focus the image on the retina.


Many hyperopic (farsighted) people with refractive errors between +.25 and +2 (less so at +2) can use accommodation to achieve good focus without using glasses. However, this 'mild overcorrecting' results in an early form of presbyopia called 'premature presbyopia'. See presbyopia below. Any + prescription above +2 generally means the hyperope needs glasses for far and near vision, i.e., the glasses make them equivalent to an emmetrope.

A diopter of 0 indicates no refractive error, and is called plano.

The minus (-) diopters (for correcting myopia) indicate a concave lens (bows inward) is needed in eyeglasses or contacts to 'decrease the bend' of inbound light rays before they enter the eye. In this case, the image without correction reaches 'focus' in front of the retina. By the time it reaches the retina, it is out of focus to some degree. The concave lens 'reduces the bend' of the light so that the cornea and lens can successfully focus the image on the retina.

Astigmatism is another refractive error and is fairly common with myopes (about 20% of myopes have some degree of correctable regular astigmatism). Unlike myopia or hyperopia, that is rarely caused by a cornea that is "too steep" (a favorite marketing statement by refractive surgeons) or "too flat" (note: it is almost always an elongated or shortened eye ball), astigmatism is almost always caused by cornea irregularity. Regular astigmatism is measured in diopters and cylinder meridian or axis. As mentioned at the beginning of this site, astigmatism will not be discussed extensively. Astigmatism, unless above 2 diopters, is not a major problem during the day when the pupil is smallest. Astigmatism, depending on its severity, may affect daytime vision, but it always affects low light and night vision, sometimes severely. Astigmatism is defined across a meridian or axis. If the cornea was mapped into wedges, two opposing wedges would be a meridian. Regular astigmatism is often described as having a 'bowtie' appearance on color topography maps.

For example, an eye with the following refraction "-3, sphere" has a mild myopic error of -3 and no astigmatism; an eye with the following refraction "-4, +1.5, 180" has a myopic error of -4 with an astigmatic error of +1.5 in the 180 degree meridian (180 degrees is straight across (horizontal) the eye). To understand astigmatism and refractive prescriptions fully requires a lengthy explanation. The major public libraries have two books that provide good discussions of astigmatism, diopters and prescriptions. A good layman's discussion of astigmatism can be found in As I See It by Raymond Munna. A much more extensive discussion can be found in Eye and Its Disorders by Trevor-Roper and Curran. There are numerous other books at the library - get out from in front of the monitor!

Astigmatism below 1 diopter (+ or -) is generally considered a minor vision problem and easily corrected. It is important to understand the difference between regular and irregular astigmatism. Whereas regular astigmatism can be corrected (to a major extent) by corrective lenses and contacts, irregular astigmatism cannot be effectively corrected. Irregular astigmatism can take on all kinds of unusual surface curvatures (especially after refractive surgery). In some cases, irregular astigmatism can be improved (but not corrected) by substituting a 'best fit' regular astigmatism cylinder correction. Irregular astigmatism is a common (and sometimes severe) optical problem after cornea injury or cornea surgery (such as RK, PRK or LASIK). The effect of irregular astigmatism is most prevalent when the pupil is fully dilated, or looking at sharp contrast objects under low to medium lighting (like reading or watching movies at a movie theater). It is discussed further in the Complications of Refractive Surgery section.

EyeKnowWhy has grouped the diopter ranges and their characteristics into the following table.

General Diopter Grouping
Diopter Range Type Description
+15 to +6 Very High Hyperopia Not Common
+6 to +2 Moderate Hyperopia Common; Requires bifocal after 40 or reading glasses even earlier.
+.25 to +2 Very Mild to Mild Hyperopia Common; Often masked by accommodation. May require bifocals after 40. A mild hyperope can often 'see' 20/20 prior to loss of lens accommodation and be farsighted +2 diopters or more. Diopters do not have an absolute relation to snellen (i.e., 20/40 is often assumed to mean an error of +/- 1 Diopter, but this is not necessarily true.)
0 (plano) Emmetrope Common; No Refractive Error; May require reading glasses after 40 NOTE: A person can be emmetrope and see less than 20/20 due to ocular disease.
-.25 to -3 Mild Myopia Common; Could be considered the optimal vision for old age. May avoid reading glasses until 60's or later. About 70% of the myopic U.S. adult population falls within this range.
-3 to -6 Moderate Myopia Less Common Than Mild Myopia; May avoid reading glasses until much later in later life but these myopes have less functional vision than mild myopes.
-6 to -25 High/Very High Myopia Not common; No effective close vision without glasses. These myopes do need solutions to their severe myopia, and are the most motivated candidates for refractive surgery.

Regular Astigmatism (Cylinder)
+/- .25 to +/- 1 D Mild Common; Generally not a significant problem, most noticeable when pupil is dilated.
+/- 1 to +/- 3 D Moderate Less Common; More difficult to correct, but usually successful.
+/-3 and higher High Not Common; Can be a significant problem, and difficult to correct with glasses and contacts.
Table Caveats: All ranges and descriptions are approximate.

Click here for MORE discussion within this topic (Refractive Errors). After reading the extended discussion, use your browser back key to return here.

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The Cornea - A Detailed Look at Its Tissue Structure

The cornea is far more than meets the eye. It is a complex structure with a multitude of functions and extraordinary complexity. Considering its transparency, absence of blood vessels, and ability to withstand the insults of modern life from smoke, fumes, cosmetics, opportunistic organisms and active lifestyles, its ability to maintain its transparency for the entire life of an individual is remarkable. Nevertheless, it is subject to transparency threatening complications. The most serious of these is infections by viruses, bacteria or fungus (organisms) and trauma, accidental or intentional.

Click here for MORE discussion within this topic (Cornea Tissue). After reading the extended discussion, use your browser back key to return here.

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Clarifying Important Concepts

General concepts related to vision and surgery are often misunderstood by the public.

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eyechartAssessing Refractive Errors and Snellen Visual Acuity Testing.

Post operative patients are always saying 'I see 20/15 with my left eye, and 20/25 with my right eye' or 'I'm 20/20 now.' or 'I can see 20/30 without glasses.', 'Night vision isn't that much of a problem.', 'Glare and halos are only occasionally noticeable.', or 'I only need to wear glasses to drive at night.' Just what does all this mean?

Everyone is familiar with a Snellen eyechart, big 'E' at the top, and lines of letters decreasing in size. A person who can 'read' the 20/20 line is said to have '20/20 vision'. But is that misleading? It depends.

Do you remember the testing that occurred at your last eye exam? One or two? Two or three? During that process, the examiner is fine tuning your spherical (myopic or hyperopic) and cylinder (astigmatism) lens power for best corrected vision. You may also recall eyedrops to paralyze the lens and prevent accommodation from masking mild hyperopia. During the last part of the process, you are still reading the same '20/20' line; they are just making it sharp! Other tests are done to evaluate your contrast sensitivity in normal and low light conditions, peripheral vision, retina health, cornea health, pupil dilation, and other eye functions. The point is, that Snellen, although commonly used as the 'standard' for visual acuity, can be misleading.

The term 20/20 DOES NOT MEAN EMMETROPIA (i.e plano or zero correction needed) or exceptional quality of vision or peak function of vision or excellent night vision or excellent contrast sensitivity or absence of glare or visual distortion or regular astigmatism or irregular astigmatism or early cataract formation or a host of other things such as abnormal tearing, eye pain, glaucoma, eye throb, headaches, and equality of visual acuity between the two eyes. Those are discerned by other tests and in many cases rely on patient subjectivity and must be assessed separately. However in normal unscarred myopic eyes with mild to moderate myopia and mild to moderate astigmatism, these other assessments are normal or very close to normal when corrected by eyeglasses or contacts.

RK Cornea - 3 yr. postop w/uncorrected VA = 20/30It is possible (and often likely) that people who have refractive surgery can have several of the above other factors be mildly or significantly worse than before surgery and be able to 'read' the 20/20 line. For example, the cornea to the left has undergone RK resulting in significant scarring, but the uncorrected visual acuity is 20/30 (based on Snellen line read). Whether this patient is happy is subjective, and whether that happiness will last is undetermined.

EyeKnowWhy located two trade magazine articles online that discuss patient satisfaction after PRK (note these surveys had a very low return rate for questionnaires):
EuroTimes - 1994, (patient satisfaction; some what old but enlightening)
UPDATE: Sorry, this article is no longer available to the public - now membership only protected. This article showed about 75% of patients were satisfied after two years. Many patients complained about night vision effects, and ghost vision.
Eyeworld - Patient Survey Shows High PRK Satisfaction - Feature Article http://www.eyeworld.org/March/patientsurvey61.html.html {UPDATE: Sorry, this article is no longer available to the public - now membership only protected. Basically it said that one year after PRK 85% are happy and 15% are unhappy. Patients report persistent night vision problems.

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Refractive Surgery, Decreased Visual Acuity, and the Risk of Blindness

Clear Cornea - Unaltered The picture to the left is a clear unaltered cornea. Refractive surgery does damage, scar and distort the cornea structure, but very rarely results in blindness. This has been shown throughout the ophthalmology journals. There are pictures of corneas that have undergone numerous procedures, developed severe scarring and irregular astigmatism, but the eye is not blind. Amazingly, some of the eyes (using the scarred and distorted cornea pictured in the journal study) actually have uncorrected visual acuity of 20/40 or better (remember the limitations of Snellen testing).

"Corneal Scars are the inevitable sequel to any injury of the cornea that transgresses Bowman's membrane. The extent of such scars necessarily depends on the extent of the injury to the cornea lamellae [i.e., tissue layers] and the vehemence of any superadded infection; the amount of clearance of such scars is dependent on the youth of the patient, becoming proportionately less as age advances.

Scars are termed nebulas if they are translucent 'cloudlets', and leucomas if they are dense and 'white'. The degree of visual impairment depends partly on the position of the scar (axial opacities causing gross visual loss and peripheral opacities none), and partly on the density of the scar - the slighter 'nebulas' causing, paradoxically, more confusion than the opaque leucomas, since the former allow distorted light rays to reach the retina, giving vicarious stimulation, while the totally opaque leucoma merely reduces the number of entrant rays." From Eye and Its Disorders, Trevor-Roper and Curran, 2nd Ed., P. 379

The good news is that cornea scars (or severe cornea haze) do diminish (albeit slowly) in the majority of eyes in the years following cornea surgery.

Vision Threatening Complications and Risk of Vision Impairment

Although corneas that are damaged or scarred by refractive surgery can perform, and even perform well, all prospective patients should be aware that vision threatening complications may occur after surgery (immediately or delayed for months or years). There are six critical complications that may occur after refractive surgeon (or in natural aging or accidental eye trauma) that can lead to legal blindness or absolute blindness in the affected eye: uncontrolled infection, cornea ulceration, cornea rupture, cataract, retinal hemorrhage, detachment and failure, and optic nerve atrophy/disease.

Vision impairment is more difficult to define. It is not just an inability to read the same Snellen line with glasses after surgery as you could with glasses before surgery.

Vision threatening complications and an assessment of vision impairment with examples are provided in the extended discussion page Vision Threatening Complications and Vision Impairment Examples.

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How the Cornea Heals

Because the cornea is avascular (without blood vessels), all cornea wounds of any substantial size heal slowly over many years. This prolonged period is called cornea wound remodeling. However, EyeKnowWhy divides corneal wound healing into four stages. The four stages after wound trauma that penetrates Bowman's Membrane are a)initial barrier restoral and epithelial infill, b) cornea recovery and wound healing initiation, c) scar formation, and finally, d) long term cornea wound remodeling. All cornea wounds that penetrate Bowman's Membrane heal by scar formation. For each type of refractive surgery (Radial Keratotomy - RK, Photorefractive Keratectomy - PRK, and Laser Assisted In-Situ Keratomeuliesis - LASIK), these stages have slightly different characteristics.

Click here for MORE discussion within this topic (Cornea Healing). After reading the extended discussion, use your browser back key to return here.

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Patient Happiness and Unhappiness

What makes a postop happy or unhappy? It depends on a number of things. Results, expectations, and time since surgery all play a major role in a postop's happiness or unhappiness. Patients who have poor results or 'significant' complications are obviously unhappy. People who like 'things just right' should avoid refractive surgery. People who are bothered by persistent 'visual quirks' (e.g., glare, halos, transient wakeup edema, reduced night vision) after refractive surgery should avoid it entirely. For example, it is quite possible for a person who had an excellent outcome in relation to most postops will be unhappy because of mild side effects. A 'finicky' patient with an excellent outcome may dislike seeing halos and be very dissatisfied. A person with severe myopia or astigmatism may be happy with improvements that would be very unsatisfactory for a mild or moderate myope. You also have to look at happiness over the very long term. A person in their 30's who is mildly overcorrected may be upset when he needs reading glasses to read or do close work in his early 40's. Also, if a person regresses or progresses or develops a 'significant' complication five, ten or twenty years after surgery, they may become unhappy then. Surveys show about 90% to 96% of patients are happy (or satisfied) at the end of year one, but these surveys are sometimes questionable due to nonresponse, and the subjective nature of the questionnaire. It just "depends". Remember, every minute you are awake and for the rest of your life, you will 'see' the results and side effects, if any, of refractive surgery.

Click here for MORE discussion within this topic (Patient Happiness/Unhappiness). After reading the extended discussion, use your browser back key to return here.

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The FDA is supposed to protect and serve the public but that is not how it always works. Of all the regulatory agencies in the world responsible for protecting that country's citizens from health fraud and unsafe drugs and medical devices, it is generally considered the best.

The History of the FDA

Prior to the FDA's establishment by Congress, Americans were often the victims of health care fraud and dangerous drugs and medical devices. Originally chartered to regulate drugs and food, in 1976 Congress expanded the FDA's authority to include medical devices. Medical devices prior to 1976 were 'grandfathered'. After 1976, medical devices were assigned classes; Class I devices present the least risk, Class II are a step up, and Class III present the greatest risk to patients. All new medical devices are classified, and in some cases a device could bypass almost all regulatory review by obtaining a 'substantial equivalency' designation. Substantial equivalency is somewhat controversial but will not be discussed further here. As the FDA has matured, and its critical importance to the welfare of the U.S. population (as well as drug and medical device manufacturers bottom line) has become recognized, it has come under fire on all sides. Consumer health advocates argue that reviews are flawed, and 'safety and effectiveness' standards are too low. Manufacturers argue the review process is too complex, too lengthy, and standards and review costs too high. Some things the FDA does well. There are many drugs and medical devices that never make it to market and harm thousands, if not millions of people, because of problems uncovered by FDA review. But there are perceived failures. For example, the Dalkon shield and breast implants, Fen/Phen (still controversial) and Olestra (fake fat). Like any agency that decides the fate of products with billions (that's billions) of dollars in potential revenue at stake, it also is subject to intense lobbying. Lobbying can be direct or indirect. Drug and device manufacturers do not give money to politicians without cause. Likewise, the indirect lobbying is even more invisible. Regulatory coordinators for manufacturers may have too cozy of a relationship with FDA staff. Medical 'associations' may pressure the FDA to approve products. FDA review panels may be dominated by physicians with conflicts of interests. FDA staff may consider job opportunities with manufacturers after leaving the FDA in their review decisions.

Because of the above and other possible conflicts, any FDA approval of a drug or medical device must be considered with some skepticism and understanding of what 'reasonable safety and effectiveness' means. Do not rely on any regulatory agency to protect you from unethical, incompetent doctors or surgeons, or questionable medical treatments and surgical procedures.

Click here for MORE discussion within this topic (FDA). After reading the extended discussion, use your browser back key to return here.

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RK Eye Icon The History of Refractive Surgery - Through Radial Keratotomy

As early as the 19th century there were observations that some individuals who experienced cornea injury experienced significant changes in visual acuity. In very rare events, nearsighted trauma victims may experience a dramatic decrease in their nearsightedness. It was also observed that these positive changes in visual acuity were often accompanied by a wide array of visual aberrations and ocular disease symptoms associated with trauma to the cornea and eye. Not much was thought of it.

In the early 1950's, a Japanese eye surgeon, Dr. Sato began experimenting with placing primitive cuts in the corneas of volunteer myopes. These cuts were around the outermost part of the cornea, were numerous, and completed with a scalpel that often penetrated into the chamber. Occasionally, the resulting scarred and deformed cornea did somewhat improve vision, but complications were common and severe. Sato eventually abandoned this early form of radial keratotomy, but only after operating on thousands of corneas. The long term results of Sato's surgery are well known - almost all of his 'volunteers' are now blind as documented in the Contact Lens Association of Ophthalmology Journal and the American Journal of Ophthalmology articles (CLAO J, "Problems arising from Sato's radial keratotomy procedure in Japan", Akiyama K., Tanaka M., Kanai A., Nakajima A., Vol. 10 P 179, 1984; Am. Jrnl. Ophthalmology,, "30 year follow-up of posterior radial keratotomy", Beatty R.F., Smith R.E., Vol. 103, P. 330, 1987.) These are not available online.

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RK Eye Icon'Modern' Radial Keratotomy Is Born

Around 1973, a Russian eye surgeon named Vyataslov Fyodorov experimented with Sato's incision technique, and 'modern' Radial Keratotomy (RK) was born. There has been a legend associated with Fyodorov's RK involving a patient of Fyodorov's RK. As the story goes, this patient came to Fyodorov with glass fragments (in his cornea(s)). Dr. Fyodorov removed the fragments (which supposedly had not penetrated the anterior chamber (the liquid filled void just behind the cornea and before the iris/lens complex). Rather than suturing the lacerations, Fyodorov allowed them to remain gaped open and heal by scar infill. After experimenting on rabbits and other animals for a few years, Fyodorov began experimenting on human corneas. Claims of tremendous 'success' were met with skepticism. Nevertheless, 'pioneering' U.S. eye surgeons trekked to Russia, and learned Fyodorov's Russian RK technique. Radial Keratotomy was introduced to the U.S. in 1978 by these 'pioneers'. Fyodorov went on to invent "assembly line RK" surgery at his clinic in Russia. In this 'factory', patients are placed on gurneys that are on automated tracks. By moving through a procedure 'factory', RK is broken down into individual processes and large numbers of patients can be done during a day. There is an amazing picture of this process in the National Geographic, Nov. 1992 issue ("The Sense of Sight") (Click Here to see Fyodorov's Assembly Line RK Factory), and a witty interview with Fyodorov and a site visit to the surgical suite in his Moscow clinic in Health, Nov./Dec. 1993 "Sight for Four Eyes" by Mary Roach.

Because RK uses only a knife in the surgical process, there is no oversight or regulatory review requirement, government or peer. RK - Marking and Stabbing IncisionsThis is important to understand because it explains how the wide scale marketing of keratotomy ('cut the cornea') procedures in the U.S came about. No government regulation or review means anyone with a medical degree of some type and a scalpel can perform RK or any other refractive surgery procedure such as ALK, AK, HK (Hexagonal Keratotomy), using only a knife and common eyecare instruments with no or minimal training - all it takes is a patient willing to sign a consent form. Up until 1982, there was no credible large scale, long term study of the safety and effectiveness of RK. During 1982, the National Eye Institute, a division of the U.S. National Institute of Health, under the directorship of Dr. Carl Kupfer, funded a multicenter, multiyear study of RK. A coalition of refractive surgeons under the leadership of Dr. George Waring, Emory University, began the study with the well recognized name PERK for Prospective Evaluation of Radial Keratotomy. Besides reporting summaries of PERK outcomes, many specialized substudies of RK surgery effects in the PERK 'volunteers' have been published. These 'substudies' and the PERK summaries have been published in peer reviewed ophthalmology journals. In reviewing any refractive surgery study and its conclusions, please keep in mind potential conflicts of interest by its authors and the credibility of their conclusions.

The PERK study enrolled 435 patients in 1983 and 1984. Of these, 792 eyes were operated on. This represents approximately 80% of the PERK study group that had both corneas surgically altered, and 20% who declined surgery on the second eye. For safety reasons (in case of disastrous complications such as infections and retinal detachments), patients had to wait at least 1 year before having the second eye done (note: a few did not). One of the questions you may ask is "If RK is so 'bad', why did 80% choose to have the second eye done? Patient reasons vary - some had a 'good' outcome with the first eye, and wanted to do the second. Others had difficulty with anisometropia (refractive mismatch between the two eyes) and believed it would be better to try and bring the acuity of the second eye more in line with the first. Others were unhappy with the first and refused surgery on the second eye. Patients' decision to have the second eye operated on is complex and in some cases illogical. Complications of keratotomy surgery are well known and well documented in the ophthalmology journals.

12 Cuts and Scars - RK To the left is a typical 12 cut RK done in 1995. You can clearly see the debilitating scarring that resulted. In this patient, the uncorrected visual acuity was 20/30 - 20/40 after surgery (based on their ability to discern letters on a Snellen eye chart), but vision quality was debilitating. This patient is not happy though they are considered a "clinical success."

Click here for MORE discussion within this topic (RK). After reading the extended discussion, use your browser back key to return here.

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PRK Eye IconThe History of Refractive Surgery - Today's Laser Surgery

In 1983, it was postulated that the excimer laser may be viable in modifying the cornea structure. Two companies eventually emerged to pursue development of excimer laser surgery on the cornea, Visx and Summit. Initial designs were to use the excimer laser to make the RK cuts rather than a knife. This didn't work well and was abandoned. The alternative technique was to reshape the central and mid optical zone of the cornea by using a diaphragm (mechanical iris) to create a flattening of the central cornea. By 1988, Visx and Summit applied and received Investigational Device Exemptions (IDEs) from the FDA.

PRK Eye IconPhotorefractive Keratectomy - Details and Analysis

You can visit numerous web sites to get an idea of the overall clinical procedure and preparation. This site focuses on the physical details of PRK during the procedure, and the wound healing that occurs during the initial year. With PRK, wound creation is done in the central optical axis and the peripheral area is left untouched. Three of the recognized difficulties of the PRK procedure is stripping the epithelium, centering of the ablation wound and consistent ablation as tissue removal progresses. Once the patient has been trained to focus on the light and the eye has been anesthetized, the epithelium must be removed. This is quite traumatic to the cornea as you can well imagine. Current techniques are scraping with a spatula blade, dissolving with chemicals or ablation with a few pulses of the laser. PRK Plume Frame After removing the epithelium, the laser is then fired successively building a crater shaped wound as Bowman's Membrane and part of the underlying stroma is ablated. PRK achieves tissue destruction by pulsing on and off UV laser exposures. Each laser pulse is rapidly absorbed by the cornea tissue. The internal water of the cornea surface cells rapidly boils, vaporizes and expands, exploding the cell walls. This is a picture taken with extreme magnification showing the 'plume' of tissue debris being ejected from the cornea surface after a pulse of laser light. One of the problems that plagues PRK is uneven stroma removal resulting in elevated spots of stroma tissue in the central optical zone (central islands), or in some cases, excessive tissue removal spots (keyholes,pits). The causes are complex, and relate to fluid movement from exploded cells between UV exposures inhibiting ablation during subsequent pulses, and difficulty in managing consistent laser energy across the diameter of the beam thoughout the ablation process.. Another problem is transitioning from the ablation wound to the unablated cornea tissue. Off center wound profiles are a problem and relate to poor initial alignment (with the central optical axis), patient focus drift (not keeping their eye on the 'little light'), and saccadic (involuntary) eye movement. Did you know your eye is always moving even when you are staring? It's small and involuntary, and is called saccadic eye movement.

PRK to correct myopia involves removing tissue from the central and mid cornea. The reduction in refractive power is achieved by removing more tissue from the center of the cornea than from the midzone cornea. This results in a reduction of the refraction or bending of the rays passing through the ablated parts of the cornea, and thus moves the image farther back toward the retina. Overcorrection occurs when the changed curvature is too great, moving the image 'beyond' the retina resulting in farsightedness. Astigmatism is 'corrected' by cutting away a pie shaped section of the cornea along the angle of the cornea's steeper sections. Farsightedness is corrected by cutting a circular 'trench' called an annullus along the midzone of the cornea, and progressively carving less tissue at the center of the cornea. The annulus is usually created at a diameter of six or more millimeters to reduce night vision aberrations which can be severe. Newer farsighted techniques moves this annulus out to seven or eight millimeters. The resulting effect is a steepened 'hill' in the central zone. Because a farsighted 'sculping' is more irregular than a myopia 'flattening', it is more difficult to create, and the cornea's physiology does not 'seem to like' the steepened central zone. A stroma and epithelial fillin response occurs causing significant regression. The peripheral annulus tends to produce a more profound scarring response as well. Currently, only myopia and astigmatism have been approved by the FDA. Astigmatism ablations tend to cause a stronger wound response, and more optical side effects such as irregular astigmatism, glare, halos, arcs, and starbursts.

The picture to the left is a scanning electron microscope (SEM) photo immediately after PRK myopia ablation, PRK Ablation and reflects the smooth 'cutting' of cornea tissue by the excimer laser. The central zone (3) is fully ablated, and a transition zone (2) merges into the epithelium (1). Newer excimer lasers and scanning lasers supposedly provide a smoother transition zone than that shown here. The epithelium within the ablation zone is removed prior to ablation.

The ablation technique for myopic, astigmatism and hyperopia for LASIK is the same as PRK, except it is done on the stroma exposed after the flap is lifted out of the way. One notable difference is that the ablation depth for LASIK may be adjusted compared to that for PRK, since a PRK ablation may include extra ablation pulses to compensate for stroma regrowth which does not seem to occur after LASIK. In addition, any additiional adjustments for central island prevention may need to be adjusted as well since central island formation may be different for LASIK than PRK for the same attempted correction. This 'fine tuning' is established as experience progresses, and is a very good reason NOT to be the first for a 'new and improved' version of the laser. Let others get these early and easily corrected 'bugs' out.

Epithelial regeneration is a complex problem following PRK. As you may recall, the epithelium is normally 6 cell layers thick, and the lowest layer is known as basal cells. After PRK, there is no Bowman's Membrane remaining within the ablation wound area. Within the first 3 days (sometimes less, sometimes more), a layer one to two cell layers thick of epithelium regenerates from the edge of the ablation wound. This is critical to prevent infection and rapidly reduces eye pain stimulated by the residual nerves in the exposed stroma.

Because Bowman's Membrane is destroyed, a scar wound healing response is evoked after PRK. PRK Haze Grade 2+ This scarring that occurs in the ablation wound manifests itself as a haze under the slit lamp. Haze (or scarring) is assessed on a scale of 0 (no haze, clear cornea) to 5 (severe scarring and degradation of vision). Most eyes begin to develop a hazy scar between 1 and 2 months after surgery. Over the next 12 months, this haze does decrease. Despite the PRK scar/haze scale, assessment is still fairly subjective. 'Trace' haze and sometimes the wound edge can be detected in almost all eyes with the appropriate slit lamp angle, lighting and magnification at 12 months. Still, haze graded below 1 (often called 'trace') does not seem to impair vision although it may increase GASH. The picture to the left is a PRK eye at 12 months with grade 2 haze/scarring.

One of the subset studies that was performed within the FDA PRK trials was using PRK after 'failed' RK surgery. The results were poor. PRK After RK Haze In many cases, substantial haze and scarring developed, healing was slower and more problematic than in eyes that had no previous surgery and significant reductions in best spectacle corrected visual acuity (BSCVA) occurred. Despite this, there are refractive surgeons who market PRK to RK patients seeking solutions to their vision problems. If anything, EyeKnowWhy hopes that RK patients do extensive research before attempting PRK or LASIK surgery over a cornea compromised by RK scars. The photo to the left is a cornea that developed substantial haze after PRK after RK. The white lines are the RK scars.

If anything comes out of your reading this site, it is that RK and AK are bad ideas and should be avoided by everyone. You have to be really wary of any surgeon who defends any type of keratotomy procedure (RK or AK).

Because laser refractive surgery is so financially lucrative, some disturbing trends have occurred. The advent of 'black box' lasers, changes in 'treatment techniques' without adequate clinical research, and the promotion of new surgical procedures such as LASIK without adequate research are increasingly common.

Black box lasers are particularly disturbing. Since these excimer lasers are made without quality controls associated with lasers undergoing FDA trials, the risks to the patient increase significantly. Is the 'power' of the excimer beam calibrated correctly? Does this machine perform consistently? Black box lasers began showing up in 1995, and a few are still in operation today. The following are news stories in the online journals regarding 'black box' lasers:

LASIK Eye IconLaser Assisted In-situ Keratomileusis (LASIK) - New and Unproven

LASIK is the newest technique promoted for 'vision correction'. LASIK is being marketed as the solution for almost all refractive errors (severe myopia, high astigmatism and hyperopia) and for rapid recovery and 'fast' healing. It was the predominant surgical procedure worldwide by the end of 1997. Still to look at it in detail, it is certainly an 'intense' procedure requiring great skill to get that flap just right. If you haven't reviewed other sites promoting LASIK, do so now.

Some sites you may visit are:

Laser Site (The Vision Correction Website)
Emory Vision Correction Center

The 4 Steps of a LASIK Procedure

LASIK Multiset - 4 steps

LASIK is PRK with a flap of surface tissue that is placed over the ablation wound. This is where great skill, surgical experience and the right keratome (cutting device) are really critical.

When the flap cutting and relaying of the flap over the ablated stroma 'bed' is done, things can go very badly, with devastating results. Some of the known problems are lopsided and decentered cuts, complete detachment resulting in a 'cap', thin caps and flaps, rough flap edge due to blade 'chatter' during cutting, cap/flap wrinkle, epithelium ingrowth, adverse growth of striae (collagen fibrils between bed and flap), caps lost, cap/flap necrosis and 'fall off', cornea ecstasia, central islands and keyholes in the ablated stroma, and irregular astigmatism.

Because the microkeratome is considered a "finicky" machine and subject to failure and inconsistent cuts, new flap cutting techniques using a fine jet of high pressure water to cut the flap are under investigation. Initial clinical trials have shown this to be promising with less shredding of the stroma tissue (compared to the keratome reciprocating blade), improved operational view, and decreased need to pressurize the eye (During the current keratome cut, the eye's internal pressure must be raised to approximatley 65 Hg - an eye's regular pressure is less than 20 hg - to distort and flatten the cornea for the lamellar cut pass of the blade). This "waterjet" cutting device is also being looked at as providing a cleaner and smoother removal of the epithelium for surface PRK as well. Waterjet is expected to be available in 1999. Newer blade microkeratomes with easier operation, transparent head compoents for viewing of the cutting process by the surgeon, and disposable blade assemblies are also in clinical trials. Since these new keratomes and the waterjet will be classified as "substantial equivalent" equipment to older keratomes, FDA approval will be expedited.

Because the flap provides a 'preserved' layer of epithelium and Bowman's Membrane, the immediate (within a week) visual results can be remarkable if done right, and there is a lot that must go right. When it does go right, the results can be dramatic, especially for the severely myopic. Still, this is a major incision across the horizontal plane of the cornea, and the issue of the type of wound healing that occurs between the cap/flap and the stroma bed, as well as the long term viability of the flap are concerns. Is the cell nourishment and hydration of the stroma bed and flap tissue impeded by the horizontal incision? Only time will tell. Many refractive surgeons favor LASIK because it leaves Bowman's Membrane intact over the optical zone, and avoids the problem of the epithelium infrastructure having to rebuild from scratch over a foreign subsurface (the now exposed stroma). Although these are reasonable arguments, the creation of the flap is a considerable risk and the long term viability of the flap beyond a couple of years has not been fully studied. Flap manipulation must be kept to an absolute minimum to prevent epithelium abrasions, "lacquer cracks" in Bowman's due to excessive bending and pressure, and unintentional "tear loose" of the flap at the hinge. Most refractive surgeons believe the flap will remain viable but the actual types of long term flap complications and their frequency will not be known for many years.

LASIK also is considerably less painful than PRK because the epithelium and Bowman's membrane is largely left intact. This assumes a successful and clean "flap creation." Also, enhancements for LASIK are "easier" than PRK because you can relift the flap (for a set period of time) whereas in PRK, the epithelium has to be rescraped and go through the painful and sometimes unpredictable regeneration process. Of course a "bad" LASIK, and especially a "bad" flap, can be a real nightmare.

You should visit the Better Health and Medical Network (AOL only) and review the postings on the Vision board. Some posters have had excellent results and some have had disturbing results.

First Person Experiences There have been articles in two of the ophthalmology trade magazines relating LASIK experiences. They are:

OSN: Patient's third LASIK enhancement procedure - 1st person

My Eye: An Ophthalmologist's First-Person Comparison Of LASIK and RK (Yes, there are a 'few' refractive surgeons who have had surgery themselves.){UPDATE: This article not available due to membership only restrictions. Basically, a refractive surgeon in Atlanta had RK years ago in one eye. Recently, he had LASIK in the other eye.

Other Laser and Non-Laser Refractive Surgery Techniques

Excimer laser technology continues to evolve. There are numerous new excimer laser 'machines' and non-laser techniques that are being tried. New excimer lasers by Lasersight, Chiron, ATC, Novatec, Aesculap-Meditec, and Nidek claim to perform PRK and LASIK ablations more accurately and are claimed to be safer than the current Summit and Visx lasers.

New beam techniques (narrow, scanning, 'flying spot') and eye tracking are in clinical trials. The Summit Omnimed, VISX Star and VISX StarS2 use what is known as a 'broad beam' where the beam is controlled by an iris diaphragm, and expands from the center to the perimeter of the planned ablation wound. The newer lasers (currently in clinical trials in the US, and available unrestricted in other countries) have optical systems that allow the beam size to be controlled in a variety of ways, and move about the ablation area. Small 'scanning beams' such as the 'rectangular slit' of the Nidek and the 'flying spot' of the Autonomous LadarTracking and Chiron Technolas 217 transfer less energy per pulse (due to their small size). Theoretically, controlling the beam movement and overlaying many small ablations result in a smoother and more accurate ablation, and optimal wound transition edge. Likewise, these scanning beams are supposed to provide more accurate astigmatic ablations, and have been recently promoted as capable of hyperopia treatments. They all destroy Bowman's Membrane during PRK wound creation.

There are currently nine excimer laser vendors in production or clinical trials - Autonomous Technologies, Chiron Vision Technolas (217 is the latest model), Kera Technology, Lasersight, Nidek, Novatec Laser Systems, Photon Data, Summit Technology, and Visx, all with varying claims of safety and effectiveness. The Motley Fool stock message boards can be insightful regarding these companies and their marketing strategies and clinical claims. You can also access the Yahoo stock message boards for the publicly traded vendors, as well. Beware, these boards can involve heated debate. Autonomous has a site that discusses their FDA approval and their eye tracking design to reduce decentration, improved ablation wound smoothness and reduction of problems associated with saccadic eye movement. Autonomous was approved by the FDA for myopia and astigmatism in late 1998. Autonomous is currently in a merger agreeement with Summit Technology. Nidek has also been approved for myopia treatment in the US. Other lasers nearing approval include Lasersight and Bausch&Lomb/Chiron. There are sites that promote these newer technologies outside the US to US citizens that you may visit.

VISX has recently introduced a successor to the current VISX Star laser called the S2 that will have true scanning and multiple, simultaneous ablation beams and improved centration ergonomics. Although technically still a broadbeam laser, the beam splitting technique utilized appears to improve the results compared to the Star. The S2 is required to do hyperopic ablations which were approved in late 1998. Star lasers are field upgradeable to S2 capability. Currently in research is the "S3" laser which may have treatment capabilities for Irregular Astigmatism, a growing problem for some PRK and LASIK postops. The availability timeframe for this is not known.

Another type of instrument known as the 'waterjet' is being proposed as a replacement for the blade scraping, chemical dissolving, rotary brush removal or laser 'burn off' of the epithelium for PRK procedures, as well as a possible replacement for keratome blade cutting of the flap for LASIK.. Two vendors, Visijet and Medjet, are conducting clinical trials of the waterjet device. The device uses a mciroscopic pulsed stream of water to cut the cap for LASIK or a diffused stream for removal of the epithelium. These waterjet tools will NOT have to go through the same FDA review standards as PRK or LASIK since it will be considered a 'substantially equivalency' device to those currently in use for these cornea 'preparation' purposes.. Medjet is also doing preliminary research to use the water to replace the excimer for tissue sculpting, but this will require studies similar to those for excimer lasers, and would be several years away. In any case, you can visit the Medjet website to review their 'claims'.

Other laser types proposed include holmium that 'thermally' shrink collagen in small circular spots around the central optical zone in a procedure called Laser Thermal Keratoplasty (LTK). Holmium Spot Burn of Cornea The picture to the left is a post Holmium LTK cornea, and you can see the 'thermal burns' as circular spots. Pictures IMMED1 and IMMED2 were taken within 48 hours of treatment. IMMED1 using two 'rings' of thermal burns where the second ring is offset from the first, while IMMED2 shows the two rings aligned. One or two rings may be used, and the number of thermal burns per ring do vary dependent on the correction attempted. The third photo 6 WEEKS shows that the cloudiness where the heat was applied has cleared considerably. LTK is considered by some to be safer than PRK or LASIK since no cutting or ablating or tissue ocurs. Where the laser's energy is applied, the collagen within the cornea stroma 'coils' and shrinks. This produces a 'cinching' effect that results in a steepening of the area within the rings, thus a reduction in hyperopia. Current trials for upto 3 diopters of hyperopia (up to +3) appear to be good, but regression has been a problem, especially in attempts larger than +3 diopters. Clinical trials are continuing. The FDA may approve LTK from Sunrise Technologies in mid 1999 for low hyperopia. Problems with holmium include collagen regeneration, induced astigmatism, cornea 'burn', epithelial defects, and regression (note: this list in not conclusive). LTK has been promoted as a method to correct 'overcorrections' after PRK or LASIK, and this may prove to be the best treatment for PRK and LASIK patients who are rendered farsighted (versus an additional hyperopic PRK or LASIK treatment). The pool of overcorrected PRK and LASIK is expanding fairly rapidly as myopic PRK and LASIK volume grows,and these patients are usually under +3D overcorrected, and appear (based on available studies which are limited) to respond well to LTK to pull them back toward emmetropia or myopia. LTK does not treat astigmatism currently, but is in experimental trials. Another laser called the YDF laser attempts to vaporize tissue within the stroma without destroying the epithelium and Bowman's Membrane first. The vendor that attempted this surgical method was Intelligent Surgical Lasers (now defunct) and the procedure is called intrastromal photorefractive keratectomy (I-PRK). Extremely complex, I-PRK was promoted as able to overcome the problems of excimer direct surface ablation (and preservation of an intact Bowman's Membrane and epithelium regeneration). The technology was sold to another medical company who is attempting to revise the laser as a LASIK capable laser. This is experimental.

ICS segments seen through a slit lamp There are three non-laser techniques currently in FDA trials. The one furthest along is intrastromal corneal rings (ICRs) also known as intrastromal corneal segments (ICSs) that are implanted in the cornea and can supposedly be 'removed'. The vendor of ICRs is Keravision. ICRs/ICSs (marketed as "intacs") are controversial because they are invasive and require significant skill during wound creation and insertion. The ICR/ICS results are mixed and it is still invasive surgery requiring incisions into the cornea (about half to two-thirds of the cornea depth) and somewhat brutal ring insertion techniques. The two segments are inserted, one on each side, in the midzone. Different thickness of segments causes a torquing of the central cornea resulting in 'flattening' and thus reduction of myopia. Even if the rings could be removed, that would be another invasive surgery, and additional scarring and wound healing would occur. Many surgeons claim ICR is "reversible", but this claim is limited. ICR/ICSs can be seen with the naked eye with close observation and oblique lighting (see photo to the left, see arrow). ICRs are in Phase III (final stage) FDA trials for low myopia and no or minimal astigmatism.

Corneal Intacs are Clearly Visible with the Naked Eye; This shows the 'ring of iron deposits' that forms within a year of surgery. In the example to the left, the segments are clearly visible, and can be observed with the naked eye. Some have described it as a "cyborg' eye. You can also see a circular 'cloud' or ring of iron deposits that form around the inside periphery of the segments. Iron lines also form after PRK and LASIK. They do not seem to cause significant long term risk to the eye, but long term observation will be necessary.

Scarring and Precipitates Form Around Corneal Intacs at 2 Years. In the example to the left, you can see the formation of epithelial deposits and scarring (fibroblasts) around the cornea segments. There are also opaque deposits or precipitates that may have been 'drug' into the wound tunnel during insertion. Obviously, the ring segments do affect night vision producing glare and halo effects. The larger the pupil, the more severe the effect. Known complications of Intacs (Cornea ring segments) are (partial list): overcorrection, undercorrection, induced astigmatism (regular and irregular), pain, inflammation, infection, night vision problems, perforation, wound infiltrates, suture irritation (the entry wound is currently sutured closed after insertion), epithelial erosion, and scarring. In January 1999, the FDA Ophthalmic Advisory Panel recommended conditional approval for the Keravision Intrastromal Cornea Segments. FDA final approval is expected by Spring 1999. For more information on the approved range and the safety and effectiveness of this procedure, visit the Keravision web site at www.keravision.com or do appropriate search engine searches.

A 'new' version of corneaplasty has also been proposed. In this version of Ortho-K, a 'chemical' is instilled/injected into the cornea to 'break chemical bonds' making the cornea 'malleable' and easier to mold with custom RGP lenses. It is only in very early FDA trials, and no reliable details regarding its safety, effectiveness and side effects are currently available. Recently the FDA did approve a specific contact lens, the Contek, for ortho-K treatment (without the 'chemical' component) for up to 3D of myopia, however, ortho-k is not without risks, and a 'retainer' lens must be worn at least once a week to maintain the altered cornea shape.

A third technique is intraocular contact lens (ICLs) manufactured by Staar Surgical. This lens is placed behind the iris, and before the eye's natural lens. Another type of ICL is placed between the cornea and iris. One type uses claws to imbed and lock into the iris, while another using tension springs pressing against the sclera (before it transitions to the cornea). In these highly invasive procedures, a surgical cut is made at the top of the cornea (all the way through it) or cornea edge (where the cornea meets the white sclera), and a foldable intraocular lens (IOL) type 'contact lens' (similar to those used for cataract surgery) is pushed through the wound and placed in front of the iris (tension or Worst claw ICL) or between the iris and the natural lens (Staar ICL). Anterior tension ICL (placed in front of the iris and shown to the left) can be seen with the naked eye.) The Staar ICL has extended edges that hold it in place between the iris and the sac that hold the natural lens. Known complications are iris inflammation, glaucoma, cataract. Iff the ICL is not placed correctly or does not 'seat' properly, it may irritate the iris, or worse, touch the natural lens behind the iris resulting in a cataract within days or weeks of the surgery. If the lens is placed successfully and does seat properly, visual acuity can be exactly corrected, and very large degrees of refractive error may be corrected. Iris distortion, large amounts of epithelial cell loss, cataracts, glaucoma and retinal hemorrhage are known complications from clinical trials. The concept of performing invasive surgery inside the aqueous humor (the chamber between the cornea and eye) or between the iris and natural lens in a healthy eye are extremely controversial. The possibility of vision threatening complications should make anyone but those with the most serious refractive disorders wary.

Pretty much all of the complications described within this site are applicable to these newer techniques. The Usenet newsgrouop sci.med.vision may be your best source for reviewing/inquiring about these procedures.

Because the potential market is so lucrative and the demand so strong, refractive surgery and a wide variety of techniques are here to stay. It will be up to the individual consumer to research the feasibility, safety and effectiveness of any surgical procedure they contemplate (in the US and abroad). It's a good idea not to be a guinea pig for experimental or investigational surgery, especially if it's elective. It is also a good idea to go to an experienced surgeon you have thoroughly checked out. It's an individual decision and there are many patients that have results they consider a great success and decided before having surgery that the possible benefits were greater than the possible risks.

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Refractive Surgery Hype and Euphemisms

The English language (as do most languages) relies heavily on vague and subjective terms. Many terms are highly subjective, and may be interpreted to mean very different things by different people since each bring his own perspective to any issue. Some terms like 'some' and 'most' are so basic to language they are unavoidable. However, when these terms are used in the process of making critical decisions such as evaluating refractive surgery, caveats are in order. This is true of the literature and opinions regarding refractive surgery. The marketing material most patients review often contains vague claims and 'general' conclusions. The use of 'most', 'almost all', 'rare', 'significant' and other vague quantifiers is universal. Even EyeKnowWhy can't get away from them in this document! Therefore, the following provides a list of refractive surgery euphemisms, vague quantifiers, and slang you will encounter in the world of refractive surgery.

Refractive Surgery Euphemisms, Vague Quantifiers and Marketing Hype
Terms Used by Refractive Surgeons What It Usually Means
cold laser, cool laser, soft laser no such thing. The excimer laser is photochemical. The light is absorbed rapidly into the interior of cornea cells. The water in the cell vaporizes rapidly, expanding, and causing the cell walls to explode. Collateral tissue damage is considered 'minimal'. One study showed that the surface temperature of the cornea rose from 84 degrees F before the procedure to 91 degrees F by the end of the procedure.
gentle/delicate invasive,all eye surgery is invasive. Any surgical brochure that has the term 'gentle' or 'delicate' in it should put you on alert. Close up high-speed video of corneas undergoing PRK show them smoking and vibrating with each explosion - that is not gentle.
fast healing subjective, is 1 year fast healing? 3 years?
painless surgery of course it's painless, your cornea has been anesthetized with cocaine eyedrops. You can cut it with a hatchet and feel no pain.
most vague, depends on possible outcomes, general range 10% to 99% ,example, the most popular color is blue, Q. What percentage of the population chooses blue?
rare vague, general range extremes .001% to 49.9%?
very rare, almost unheard of vague, general range extremes .00001% to 10%
seems, appears one man's opinion; others may draw different conclusions
concludes, consistent with one man's opinion; others may draw different conclusions
breakthrough today's 'breakthrough' is sometimes tomorrow's medical disaster
exquisite, elegant who knows what these terms mean
enhancement a second or third round of surgery is an attempt to correct problems introduced by the initial surgery. Since when did a second procedure to correct problems with the first become known as an 'enhancement'? It is interesting to note refractive surgeons never use the term 'enhancement' in medical journals to describe repeat surgeries.
minimal vague,as in 'minimal haze'
almost vague,isn't that like 'almost' pregnant? lower range (70% ?) upper end (99.9%?)
occasionally, infrequently vague, general range extremes .00001% to 33% ?
society, institute, association these 'names' may have once had meaning but in modern society, bear little credence. For example, the term 'institute' may mean something for the National Institute of Health (NIH); but then again, a lot of refractive surgeons like to include 'institute' when naming their clinics. Another favorite word in the same vein is 'foundation.' Do not be awed by any title.

Because refractive surgery is controversial, it is no surprise that derogatory slang has developed. This list is not intended to 'indict' all refractive surgeons as greedy, unethical, incompetent and uncaring. In fact, many refractive surgeons are truthful with patients regarding the risks and believe in the surgery. However, there is a sizable minority who are financially motivated and it is up to the patient to be sure they are getting the best surgical procedure by the best surgeon.

Refractive Surgery Slang
Slang Term Description
butcher refractive surgeon, also used to refer to other surgeons in other fields
knife happy, laser crazy doctors self explanatory
GASH glare, arcs, starbursts, halos, a group of common optical aberrations after RK/PRK/LASIK, reports(anecdotal and in published studies) of long term persistence and severity vary widely
starbabies RK patients, refers to the starbursts produced by scars that grow in the incision wounds
wrecks RK patients, 'rks' pronounced as a word
cornea melting, cornea decay generic slang for cornea dystrophies and erosion of the cornea that sometimes occur after refractive surgery
cattle call marketing strategy to recruit patients with 'educational seminars'
flap and zap, slash and burn, suck, saw and sizzle LASIK
slash for cash RK
Bowman's Blasting, burn to earn PRK
moonpies PRK and LASIK patients, circular recess wound in central cornea and more intense doughnut scarring at wound edge causes a halo effect, e.g., a patient looking at the moon sees halos. Direct light sources (such as headlights, streetlights, halogens) produce a halo effect esp. at night.

SEM After Ablation -10D Attempted PRK and LASIK patients, profile of PRK wound immediately post-op using scanning electron microscope looks like a crater on the moon. The ablation transition and wound edges depicted in the picture to the left (-10 D ablation) 'smooth out' as epithelium regeneration and healing progresses. Scanning lasers should create smoother initial postop profiles.

baggage old RK and PRK patients who return after 1, 2, 5 or more years complaining of problems.
schrapnel tissue debris (collagen, DNA, cell wall fragments, etc.) that is ejected off the cornea surface with each excimer laser pulse
clueless Used to describe lay press 'health news reporters' who .have 'pedestal awe' syndrome
Pedestal Awe Syndrome the inability to believe there are unethical and incompetent professionals in significant numbers in the medical research and private medical industry with M.D and Ph.Ds after their name.
quack incompetent doctor
sunscars latent scar formation in PRK eyes due to heavy UV exposure
rationalization to convince oneself that something 'must work, has to work' despite evidence to the contrary
greed self explanatory
market frenzy a rapidly growing market for a product or service characterized by media hype and aggressive solicitation. Read this JRS editorial on 'market frenzy': http://www.slackinc.com/eye/jrs/vol115/9ed.htm

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Summary of Complications of Refractive Surgery (List and Summary)

It is impossible to name all complications of refractive surgery or accurately define percentages, severity, and duration. The reason is simple however - all human corneas heal differently (even corneas in the same person). That is, each cornea (and the eye itself) responds to trauma differently.

The following table, Refractive Surgery Complications - List Only, attempts to list known complications. An additional web page Refractive Surgery Complications - Summary and Discussion provides a summary with the frequency and characteristics for the applicable refractive surgery procedures (RK, PRK, LASIK). For greater detail or understanding of a particular complication, it will be necessary to visit your nearest medical school library.

Refractive Surgery Complications - List Only
Complication Description
Anesthesia Complications
Perforations, Micro and Macro
Off Center Cuts and Incorrect Ablations
Epithelium Tear During LASIK Flap Creation/Manipulation
Pain (Immediate PostOp and LongTerm)
Photophobia (Immediate PostOp and LongTerm)
Overcorrection (Unintended Farsightedness)/Accommodation Masking
Undercorrection (Unintended Residual Nearsightedness)
Long Term Instability (Progressive Hyperopia, Regressive Myopia, Refractive Wobble)
Anisometropia (Refractive Mismatch between Eyes)
Induced Regular Astigmatism
Induced Irregular Astigmatism
Epithelial Defects and Recurrent Erosion
Diurnal (Daily) Changes in Vision
Cornea Edema (Immediate PostOp and Short Term)
Scar Formation
Cornea Nerve Growth Disorders
Cornea Vascularization
Endothelial Cell Damage (Early and Delayed)
GASH (Glare, Arcs, Starbursts, Halos)
Reduced Contrast Sensitivity and Reduced Night Vision
Keratitis (Infectious and Sterile)
Cornea Iron Lines
Cornea Ulcers
Retina Detachments/Hemorrhages
Optic Nerve Damage/Disk Cupping
Ptosis (Droopy Eyelid, Eyelid Muscle Damage)
Cornea Rupture
Cap Dislocation (LASIK)
Flap/Cap Necrosis (LASIK)
Epithelial Ingrowth
Stomal infiltrates/Wound Contamination and Cyst Formation
Iris Damage (Iritis, Iridocyclitis, Iris Distortion)
Abnormal Pupil Dilation
Increased Floaters
Increased Intraocular Pressure(IOP) and Glaucoma
Hydration and Cell Nourishment Disorder (Theoretical)
Iatrogenic Keratectasia, Keratoconus
Complications Induced by Pregnancy/Birth Control Pills After Refractive Surgery
Complications Induced by Refractive Surgery in Subsequent Eye Surgeries
Post-operative Contact Lens Wear Problems
Fitting Glasses After Surgery
Cornea Mutagenesis (Cancer)
Non Vision Symptoms of Cornea Trauma:
Tearing/Excess mucous - Dry Eye
pain/torque pain
eye throb

The list of refractive surgery complications is not comprehensive. For more information, access EyeKnowWhy's Refractive Surgery Complications - Summary and Discussion.

Your nearest medical library is always your best source. A list of ophthalmology journal references has been provided for your review.

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How To Experience The Results of Refractive Surgery Without the Surgery

Many people would like to experience the results of refractive surgery procedures such as RK, PRK, and LASIK without having the surgery. Although impossible to experience the complete spectrum of optical aberrations and resultant visual acuities, there are some simulations possible. It is not possible to experience ocular symptoms such as edema, non specific eyethrob, etc.

Blurred Vision after PRK

Many patients describe the initial vision after treatment as 'like having Vaseline on your glasses'. You can try this. This blurred vision does clear as healing progresses.


Some have said using aluminum foil with a small hole over your glasses can generate the halo effect. Others have proposed using cling wrap over the glasses with wrinkles radiating from the center to create a starburst effect.

Less than 20/20 Vision

You can also have special prescriptions done (using the heavy discounters and cheap frames) to simulate various refractive errors. Here's an example: Your original prescription is Right Eye (OD): -4, +1.5, 90 degrees and Left Eye (OS): -3.75, +75, 60 degrees. Order glasses (as many as you want to try) with presciptions that vary from your original. Be aware your astigmatism will change (often increasing if you have no or very little astigmatism). Here's an example: overcorrect right eye - OD:-5, +1.75, 90 degrees, undercorrect left eye - OS: -3.25, +1.5, 150 degrees. Try different combinations. Your optometrist can fit you with fitting lenses in his office, but there is no substitute for seeing the world with regular glasses fitted with possible results. This will cost a little money, but is worth it. There are a wide variety of simulations possible with contact lenses or glasses such as monovision, farsightedness, anisometropia and induced astigmatism. Beware, this does not simulate GASH, reduced contrast sensitivity or ocular symptoms.

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The Rationalization of Refractive Surgeons

Many refractive surgeons argue they are 'doing the right thing' and the vast majority of postops are happy and will continue to be happy (which may be true). They claim long term complications are 'negligible' or 'are not a concern', and they don't expect to see 'large numbers' of problem patients 10, 20 or 30 years later. They claim, correctly, that the vast majority of patients are happy with the results of surgery, and that PRK and LASIK have been a breakthrough for those with significant refractive errors. They acknowledge the 'unfortunate few', and say they warn patients of the risk. Many successful postops believe refractive surgery has been a 'miracle' for them, and many surgeons believe in the surgery and its safety and effectiveness as long as the patient is aware of the risks, known and unknown. Unhappy patients do not give testimonials at seminars. Some surgeons have undergone PRK and LASIK themselves. But you have to wonder, "If they think it's the 'right thing', why do so many feel it is NOT the 'right thing' for their nearsightedness."

One ophthalmologist, describing the attitude of his colleagues that perform refractive surgery, put it this way, "After you blinded a couple of eyes, it doesn't seem to be that big of a deal". One refractive surgeon, when asked why he wouldn't have the surgery for his own myopia put it bluntly, "My eyes are too valuable." EyeKnowWhy estimates that any refractive surgeon who has done 500 RK eyes has functionally blinded at least one, and any refractive surgeon who has done 1000 PRK eyes has functionally blinded at least one. Of course, the numbers for significant vision impairment (vision loss of 2 or more lines of Snellen) are much higher. Many refractive surgeons argue the risk of significant complications are adequately low that they feel comfortable recommending the surgery to those willing to accept the risks.

Consumer Reports, in their article "Surgery Instead of Glasses" (Feb. 1994), offered a more simplistic reason for the aggressive recruitment of patients by refractive surgeons - money. It seems that Medicare and managed health care (HMOs and PPOs) have seriously reduced cataract surgery reimbursement fees, a predominant revenue generator for ophthalmologists prior to the marketing of refractive surgery. The only way to make up for the lost revenue is to do more cataract surgery and do it quicker and more efficiently or look for other surgical procedures that generate revenue and profits.

The original concept behind refractive surgery research was to find solutions for people with severe refractive disorders that cannot be corrected easily with glasses, and who had difficulty with contact lenses. Somewhere along the way, financial interests became a more predominant factor for some surgeons.

The Rationalization of Refractive Patients

Understanding the attitudes, decisions, and behavior of post operative patients is complex, and may never be completely understood. There is a strong market demand for surgical correction. Many people hate wearing glasses or contacts. Many cannot wear contact lens. Some people have unusual or extreme refractive errors (about 2% of the US population) and glasses and contacts are not good solutions. Others want to pursue certain career or sporting activities and glasses may be considered by them to be an impediment.

Myopes with severe myopia and/or high degrees of astigmatism are the most interested in refractive surgery, and for good reason. Their glasses are thick and uncomfortable, contacts are often impossible to wear, and their vision is often distorted due to image magnification and minification that occur with large refractive errors. For these people, any improvement would be wonderful. Therefore, if these patients have a 'good' outcome, they may perceive it as a 'great success' whereas a person with mild to moderate myopia who has a 'good' outcome may consider it a failure. They are used to perfect vision with their glasses and contacts, and discover postoperatively that their uncorrected acuity is 'flawed' by GASH, mild irregular astigmatism and poor night driving vision. What's more, these optical aberrations persist to some degree for years after surgery in many patients, and cannot be fully eliminated by glasses (albeit with a lower power lens). One of the ironies of refractive surgery is that the patients with the 'best' outcomes (mild to moderate myopes) are often the least satisfied since they easily achieved perfect vision with glasses or contacts. The imperfect vision after surgery (although 'good' in general acuity terms) is unsatisfactory.

One question that is consistently asked is "Why do some refractive patients lie?" when it is obvious they continue to experience optical aberrations and ocular disease symptoms. There is a social stigma to stating that your results are less than perfect. If a patient states that they have problems, the person they tell wonders 'why they did it?' and may become concerned for the individual. The emotional and quality of life issue for post operative patients is complex and difficult to segment into only a few subgroups. Over time, perceptions change. Some patients adjust and become 'happy' that were not happy, some who were 'happy' become 'unhappy', others become disillusioned and chronically depressed, and some get on with life and live with the results. Some patients appear to be in a state of 'determined denial' or cognitive dissonance. Cognitive dissonance is the clinical psychiatric diagnosis for people who realize that they've made a wrong decision but because that decision is irrevocable and, to keep their psyche intact, they decide that it really was the right decision after all (even though to the unbiased observer it obviously wasn't.)

Some patients are clearly misguided. Patients are always told " you're the rare exception that has persistent side effects". They are consistently assured that the side effects like GASH will "go away, give it time". These statements, although assuring, wear thin after the first year. As one ophthalmologist EyeKnowWhy spoke with put it, "There are a lot of people walking around with some pretty poor looking corneas and bizarre vision, and you can't tell by just looking at their corneas with the naked eye."

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Informed Consent - Not a Casual Document

Informed consent forms vary in their detail and straightforwardness. Generally, refractive surgery clinics must use a consent form that is satisfactory to their medical malpractice insurance underwriter. Although the consent form 'informs' the patient of some (but not all) risks, they all contain critical CYA ('cover your ass') clauses where the patient explicitly acknowledges acceptance of all risks. Some say nobody has gone blind, an obvious lie. Consent forms are consistently used in medical malpractice lawsuits for cosmetic, elective surgeries to blame the 'victim' for their outcome. Irregardless of verbal statements and assurances that 'significant' complications are 'almost unheard of' or 'extremely rare', the consent form is the only explicit 'conversation'. Although many refractive surgeons and their underwriters believe the consent form is a powerful barrier to damages due to refractive surgery, they have been overridden by juries based on other evidence, specifically advertising and marketing brochures that omit or greatly downplay the risks. Refractive surgeons know this and therefore walk a fine line between hype and reality in marketing refractive surgery. Anyone considering refractive surgery should review ALL forms they must sign thoroughly days before the surgery, NOT on the day of surgery after you pay for the surgery and have been drugged with a sedative.

For more information and complete examples of the informed consent forms currently in use, review our Informed Consent page.

One widely reported malpractice case involving RK and informed consent was Nicholson vs. Simon (<= Click to review now.) In this case, the jury determined that the patient was not adequately informed. EyeKnowWhy knows of four malpractice lawsuits (1 RK, 2 PRK, 1 LASIK) currently in discovery. Many lawsuits settle months or years before a publicly recorded trial.

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Employer, Government and Military Positions on Refractive Surgery

Employer restrictions on employees having refractive surgery vary widely. Some companies ban refractive surgery all together. Others inform their employees that refractive surgery is 'cosmetic' and 'elective' surgery and if the employee develops complications requiring medical services, they will not be reimbursed under the company's insurance plan. Some may also exclude disability compensation or other benefits for employees disabled by refractive surgery. Others have no restriction, and a few have insurance plans that will pay some or all of the cost of the surgeries..

Few insurance programs provided by employers (or directly purchased) pay for refractive surgery. Reasons given are cosmetic, medically unnecessary, experimental, unproven, unsatisfactory results, and excessive complications. You should check with your employer's health insurance coordinator (or if you have direct health insurance, contact the insurance provider directly) for their position on refractive surgery.

Because refractive surgery patients may be a hazard to themselves and others when driving (especially at night), companies that have employees drive company vehicles may ban surgery for those employees to eliminate the liability exposure. Companies may also implement screening programs to detect employees and applicants who had refractive surgery. Some employers may ban refractive surgery or implement employee education programs to protect them from liability exposure and to make sure employees are aware of the risks.

The U.S. government has variable positions on refractive surgery. The U.S. military will not accept any applicant that has undergone any refractive surgery. Current members of the military who undergo refractive surgery may be expelled or placed on restricted service. In all cases, the military makes clear that any enlisted person who has refractive surgery cannot use the military's health services or disability benefits due to complications of refractive surgery.

As mentioned in the PRK section, the only approved clinical trials within the military are being performed in San Diego under the auspices of Lieutenant Commander Steve Schallhorn (M.D.) and by the Army in Texas. The Navy's first phase enrolled 30 Navy seals for PRK treatment of mild myopia in 1993. These enrollees are now being monitored. The second phase involves 100 new 'volunteers'. These 130 candidates will be provided medical care and disability benefits if they become blind or severely visually impaired due to PRK treatment. The Army is also developing a clinical trial with at least 100 volunteers. Of all the studies you may review, these will probably be the most frank and truthful. The final results of these trials are expected in late 1998 or 1999. All military trials are now using VISX star 'C' lasers. The following are a few military URLs that discuss the military's evaluation of PRK:

Abstract - Navy Preliminary Results of PRK on 30 Navy Seals http://mac088.nhrc.navy.mil/Pubs/Abstract/95/11.html

Web Document - Army PRK Trial Planning Meeting http://chipmunk.apgea.army.mil/dcpm/VCP/AFOPNET/NEWSLETR/JUN96/A17JUN96.HTMUPDATE: This link is currently NOT FOUND. Attempting to relocate

Department of Defense/Air Force Position Paper on PRK
http://chipmunk.apgea.army.mil/dcpm/VCP/AFOPNET/newsletr/JUN96/A16JUN96.HTMUPDATE: This link is currently NOT FOUND. Attempting to relocate

Report on Disability Glare after PRK (NHRC Work Unit 6419)

Military Position on Refractive Surgery (RECOMMENDED)

U.S. Air Force Position on Refractive Surgery - 1997 Guideline Table of Contents (RECOMMENDED)

According to postings on the Motley Fool Message Board for VISX,refractive surgery has been removed (May 15-17th, 1997 postings) from the disqualification list for civilian pilots. That is, the FAA will allow civilian pilot license holders to have refractive surgery and pilot applicants who have had refractive surgery to apply for license provided they can pass vision tests required. Whether all commercial airlines will accept pilots who have had surgery is unclear. Pilots should be aware that if they have any eye surgery and cannot pass the rigorous vision testing (with or without glasses or contacts) required for license (and commercial employment), they risk losing their license. Pilots should check with the appropriate regulatory agency for details and prospective employers regarding their individual policies. Airlines do accept pilot applicants who have myopia or hyperopia as long as they are correctable to required standards.)

December 1997 PRK and LASIK Article in the Airplane Owner's and Pilot's Association Magazine (HIGHLY RECOMMENDED)


The FBI and CIA do not accept any applicants that have had RK, and will consider individuals that have had PRK or LASIK IF they can pass specific vision tests. Contact the FBI or CIA for additional information.

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Reporting Complications and Deceptive Marketing to Regulatory Agencies

If you feel that you have been injured by a refractive surgeon, you have two options. You can do both, or just one, or neither. First, you can sue, a difficult and lengthy procedure with no guarantee of winning. EyeKnowWhy's reference page ( http://members.aol.com/eyeknowtwo/referenc.htm ) contains several articles on refractive surgery medical malpractice that you may wish to research. Second, you can alert the appropriate regulatory agencies regarding your experience. Contact the FDA Medwatch and file a consumer report. You may also contact your state's appropriate regulatory agencies, medical review boards, and other applicable organizations.

If you believe refractive surgery clinics in your area are committing advertising fraud or are deceiving people who are attending their 'education seminars', you can complain to several regulatory agencies. The Federal Trade Commission (FTC), and your state regulatory agencies are good starting points. Let your local media health news reporters know about this site.

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Employee Education Packages for Employers

Because refractive surgery is sometimes marketed to the public as a panacea and without adequate disclosure, some employers may consider such practices adverse to the health of its employees. A model letter to employees has been created by EyeKnowWhy. You can access this document and copy the text to your harddisk. You can import them into your selected word processor and customize based on your policies. For more extensive detail, you can copy other parts of this website and incorporate them as well.

Click here to review EyeKnowWhy's model letter to employees.

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Projecting the Future Impact

Over one million Americans had RK or other keratotomy procedures by the end of 1995. During 1996, an estimated 75,000 Americans had PRK or LASIK. During 1997, an estimated 150,000 Americans will have PRK or LASIK. In 1998, an estimated 250,,000 Americans will have PRK or LASIK. By 2000, an estimated one million to two million Americans may have undergone PRK or LASIK. What are the long term risks associated with such a large percentage of the population undergoing surgical procedures on their eyes? Because so many of these individuals are young, the final results will not be known for decades. Is it a 'public safety issue' for two million Americans with impaired night driving vision to be driving at night in the year 2000? It is certainly something to think about.

Two articles you may wish to read are:

Complete copies of these are available from the Journal publishers or at a medical library that maintains these journals in their stacks or digital archives. The least expensive access is making copies at your medical library.

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Non-Surgical Vision Treatments

Although EyeKnowWhy DOES NOT endorse or use any non-surgical treatment, this site would not be complete without discussing them. The three best known treatments are orthokeratology, plus lens therapy and Bates eye relaxation and exercise techniques. There are many other treatments promoted by a wide variety of sources. Like refractive surgery, they have their fans and their critics. We will only discuss these three.


Orthokeratology is the use of contact lens to change the curvature of the cornea, therefore reducing the degree of myopia. It has been in use for many years and has its opponents and proponents. Originally, hard contact lens were used, and fitting to achieve the desired change in the curvature was basically trial and error. More recently, there have been new contact lens designs that are designed specifically for specific target changes in curvature. The newer techniques have been described as 'precision cornea molding' or PCM. In any case, it is important to find a specialist you are comfortable with to develop a lens wear program. It does take time, there are limits to the success that can be achieved, and some risks. Most programs require you to wear a series of lens for a period to attain the correction desired, and then a 'retainer' set that may need to be worn one or more times a week to prevent regression. Since orthokeratology cause changes in the cornea structure and require a contact lens to remain on the cornea for a period of time, there are risks. Like any contact lens wear, there are risks of cornea abrasions and infections. Some require you to wear the contact lens at night while you sleep, which doesn't particularly appeal to EyeKnowWhy. Cost for Ortho-K or PCM therapy runs anywhere from $500 to $1500. A search using keywords like "orthokeratology", "precision corneal molding" or PCM may yield other sites to review. There is reportedly FDA trials for a chemical solution/contact lens combination that creates the desired changes at a faster pace than earlier techniques. EyeKnowWhy does not know about the status of these clinical trials or the safety of the chemicals used. Claims for the amount of myopia that can be effectively treated vary, but it is reasonable to assume that it works best for low to moderate myopia. Recommended search strings for search engines are "corneaplasty" and "PCM" and "precision cornea moulding".

Plus Lens Therapy

This treatment advocates techniques for preventing and reducing myopia. Part of the program relies on the use + lens to promote changes in the eye structure and thus reduce myopia. EyeKnowWhy does not know whether this works, or how well it works. There are advocates and oppponents, and you can solicit numerous responses by posting an inquiry on the newsgroup sci.med.vision. It appears to work best on low to moderate myopia, and the younger you are, the better.

Bates Therapy

Bates Therapy is based on relaxation and 'refocus' techniques. Besides the orginal Bates textbooks, there have recently been additional books written about the technique. Like plus lens therapy, it has its advocates and opponents.

A recommended search quote string is "natural eyesight improvment".

Here are some links to check out:

There are several books that are recommended by some posters on sci.med.vision and other newsgroups:

Your library should also have books by Bates, Aldous Huxley and others you may check out. Ask your library to purchase books they do not have. A list of references provided by eye exercise and myopia prevention advocates has been added to the end of the reference page.

Some correspondents have asked about herbal therapies such as bilberry and eyebright. EyeKnowWhy is not knowledgeable about these but they are primarily known to improve night vision, not improve myopia. The caveat regarding herbal therapies are that they are not regulated and many people overuse herbs. Patience and judicious use is recommended to avoid toxic reactions.

Other Web Sites of Interest

The following websites may be of interest in specific research relating to patient experiences:

The following web vision message board is sponsored by a refractive surgery clinic (American Eye Institute) in Arizona, but is quite active.


The following web vision message board is sponsored by a refractive surgeon (Dr. Dave Edmiston in California.)


The following web site is a nonprofit consumer education site(CRSQA) to educate consumers considering refractive surgery. The Council for Refractive Surgery Quality Assurance (CRSQA) is a nonprofit consumer/patient health organization that certifies surgeons who perform laser and other eye surgery to reduce the need for glasses or contacts. Extensive information regarding refractive surgery. Links, bulletin board, glossary, and a list of CRSQA Certified Refractive Surgeons.


The following web site is sponsored by a Non Profit Consumer Group "SurgicalEyes" for Postops who have complications.


The following web site is sponsored by the Chicago Laser Center. Active message boards are located within this site.


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Question and Answers

Have Questions? You can click here for a section on questions and answers.

Your Own Research and Conclusions

No one can tell you what to think and believe. Although this site presents a negative viewpoint of refractive surgery, you need to do your own research, and reach your own conclusions. Excimer laser eye surgery is continuing to improve, improving the accurary and reducing the risks. It is certain that the results will be better next year and the year after. The question for those who wish to pursue these surgeries is when is it safe and effective 'enough' to be acceptable for them.

Book Turn GIFHere are some books and articles that you may consider:

Salesman Surgeon: the incredible story of an amateur in the operating room, William MacKay, as told to Maureen Mylander
Consumer Reports Feb. 1994 "Surgery Instead of Glasses?"
National Geographic Nov. 1992 "The Sense of Sight"
Business Week, "Vision Surgery: Give it the Twiceover", July 18, 1994

Men's Health, "Blinded by the Light", P. 68, Sept. 1996 Click here to read an excerpt from that article now.

Health,Nov./Dec. 1993, "Sight for Four Eyes", by Mary Roach (The Fyodorov story)
Mary Roach's "Sight for Four Eyes" article is available on the "Factory" page. Click here to go there now.

American Journal of Ophthalmology,"Keratorefractive Surgery, Success, and the Public Health (Editorial)", Maguire, Leo, (Mayo Health Clinic), Mar. 1994, P. 395 (This editorial may be one of the most important items on your reading list. Click here to read this article online.)

New YorK Times Magazine,"I Can See Clearly Now", Melinda Blau, 1997. Click here to read this article online.)
As I See It Raymond Munna (RK specific, but many topics apply to all refractive surgery procedures)
I Can See! Luther Crabb
Beyond Glasses! Franette Armstrong (new consumer book on PRK, EyeKnowWhy has not read, go to Amazon.com - has part of first chapter and reviews by refractive surgeons.) Barnes & Noble does not have the Armstrong book listed, but does provide numerous hits with an interesting list of books on keyword search 'myopia'.

There are many 'lay press' books, newspaper and magazine articles for you to read. Before making any final conclusion, spend a day at your nearest medical school library browsing articles on refractive surgery in the ophthalmology journals. Everyone has to make an informed decision based on their assessments of the possible benefits and the possible risks.

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