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Online Curriculum Vitae

My Community of Science profile is a web-based Curriculum Vitae which contains the following information:

  • contact information
  • educational background
  • other expertise
  • memberships in professional societies
  • honors and awards
  • funding received
  • publications

Scientific information not contained in my COS profile and downloadable versions of my papers can be found below.

 Who am I?

I am a Principal Scientist at Second Sight Medical Products. In the past I've worked with Dennis Dacey at the University of Washington, Don MacLeod at UCSD, and Dave Williams and Peter Lennie at the University of Rochester Center for Visual Science.

 New additions

Recent appearances: Envision 2006 Conference, Dartmouth Summer School, IEEE EMBS

Circuitry of the ganglion cell surround - Pubmed [pdf]

Retinal Physiology

After the optics of the eye form an image on the retina, the light is converted to electrical signals. The millions of neurons in the retina perform a series of complex computations and send a coded message about the outside world through the optic nerve to the brain. I've made a web page that describes the techniques we use to probe the circuitry of the living primate retina.

Adaptive Optics for Retinal Imaging and Psychophysics

Adaptive Optics (AO) is a technique that was developed for ground-based telescopes to correct the blurring caused by atmospheric turbulence. I've made a web page that explains the basics of the technique and shows why it has become a valuable tool in vision science.

Color Vision and Color Blindness

What is it like to be color blind? I can tell you, as a red/green blind person (a protanope), that chromatically challenged people function quite well in everyday life! One of my previous projects examined the benefits of monocular colored filters for color blind observers, an idea that goes back as far as James Clerk Maxwell (1855). Make sure you read the resulting paper [PubMed link] before spending your hard earned money on colored contact lenses or glasses to "cure" color blindness. Another one of my project showed that color discrimination in red/green blind observers is as good as normal people at very high light levels [pdf]. This is because very bright red and green lights are able to tickle the blue sensitive cone photoreceptors and red/green blind observers can use this information to make color discriminations. Although it wasn’t a part of the experiment, I’m sure that it would still be better to have my Mom match up my socks.


Color Vision Testing

You can test your own color vision by taking the web-based color vision test developed at City University, London.


What do color blind people see?

Vischeck is a web site developed by color vision experts to show what things look like to a color blind person. You can run Vischeck on your own image files or run Vischeck on a web page.

Refractive Surgery

Thinking of having Refractive Surgery? The lure of high profits often leads refractive surgeons to underemphasize possible complications and to overestimate post-surgery optical quality. For a more balanced view, check out the following web sites:


The excellent web site "I Know Why Refractive Surgeons Wear Glasses" was posted on AOL during 1997 and was maintained until 1999.  It seems to have disappeared, so I have re-posted it here:  Eye Know Why


Surgical Eyes is an organization founded by people with longer-term complications from refractive surgery to assist others who have had unsuccessful surgeries.


In June of 2002, the University of Rochester's Center for Visual Science hosted a three-day symposium entitled "Engineering the Eye." The symposium brought together basic scientists, clinical researchers, and engineers who shared an interest in marshalling the latest technological developments in ophthalmic optics to improve vision and retinal imaging. A number of presentations dealt with the current status of refractive surgery and the innovations that are on the horizon. You can view the schedule and some pdf and web-based versions of the talks at the symposium's web site.

Collaborators

Dennis Dacey: University of Washington: web site

Orin Packer: University of Washington: orin@u.washington.edu

Don MacLeod: University of California, San Diego: web site

Sheng He: University of Minnesota: web site

David Williams: University of Rochester: web site

Peter Lennie: New York University: web site

Austin Roorda: University of Houston: web site

Martin Lankheet: Utrecht University: M.J.M.Lankheet@bio.uu.nl

Electronic reprints of recent publications

The Classical Receptive Field Surround of Primate Parasol Ganglion Cells Is Mediated Primarily by a Non-GABAergic Pathway. M. J. McMahon, O.S. Packer & D. M. Dacey (2004), Journal of Neuroscience, 24(15) 3736-3745.  Pubmed [pdf]

L and M Cone Contributions to the Midget and Parasol Ganglion Cell Receptive Fields of Macaque Monkey Retina. L. Diller, O.S. Packer, J. Verweij, M. J. McMahon, D. R. Williams & D. M. Dacey (2004), Journal of Neuroscience, 24(5) 1079-1088.  Pubmed [pdf]

The origin of the oblique effect examined with pattern adaptation and masking. M.J. McMahon & D.I.A. MacLeod (2003), Journal of Vision, 3(3) 230-239.  Pubmed [pdf]

Retinal contrast losses and visual resolution with obliquely incident light. M.J. McMahon & D.I.A. MacLeod (2001), Journal of the Optical Society of America A, 18(11) 2692-2703.  Pubmed [pdf]

Fine structure of parvocellular receptive fields in the primate fovea revealed by laser interferometry. M.J. McMahon, M.J.M. Lankheet, P. Lennie & D.R. Williams (2000), Journal of Neuroscience, 20(5) 2043-2053.  Pubmed [pdf]

Dichromatic color vision at high light levels: Red/green discrimination using the blue-sensitive mechanism. M.J. McMahon & D.I.A. MacLeod (1998), Vision Research, 38(7) 973-983.  Pubmed [pdf]

Off-axis optical quality and retinal sampling in the human eye. D.R. Williams, P. Artal, R. Navarro, M.J. McMahon & D.H. Brainard (1996), Vision Research, 36(8) 1103-1114.  Pubmed [pdf]

Can't read pdf files? 


Conference Presentations

M.J. McMahon, S.H. Greenwald, A. Caspi, A.Roy, K.H. McClure, G.Palmer, A.Horsager I.Fine, M.S. Humayun  R.J. Greenberg (2006) Progress Using an Epiretinal Prosthesis to Provide Sight to Patients Blinded by Photoreceptor Degeneration. Envision 2006, Kansas City.

M.J. McMahon, I. Fine, S.H. Greenwald, A. Horsager, G. Palmer, B.V. Mech, R.J. Greenberg & M.S. Humayun (2006) Electrode impedance as a predictor of electrode–retina proximity and perceptual threshold in a retinal prosthesis. Annual Meeting Abstract and Program Planner. Association for Research in Vision and Ophthalmology. E-Abstract 3184.

M.S. Humayun, J. Hopkins, S.H. Greenwald, A. Horsager, A. Roy, K.H. McClure, G. Palmer, I. Fine, M.J. McMahon & R.J. Greenberg (2006) Electrical effects and perceptual performance using a chronically implanted 16–channel epiretinal prosthesis in blind subjects. Annual Meeting Abstract and Program Planner. Association for Research in Vision and Ophthalmology. E-Abstract 3212.

A. Horsager, S.H. Greenwald, M.S. Humayun, M.J. McMahon & I. Fine (2005) The perceptual effect of retinal electrical stimulation using pulse trains. Program No. 246.9. Society for Neuroscience, 2005. Online.

D.S. Hahn, F. Darvas, D. Thyerlei, M.J. McMahon, J.D. Weiland, R.M. Leahy & M.S. Humayun (2005) Spatiotemporal analysis of visually evoked potentials in the cortex of a blind subject with a chronic intraocular retinal prosthesis. Annual Meeting Abstract and Program Planner. Association for Research in Vision and Ophthalmology. E-Abstract 1496.

M.J. McMahon, O.S. Packer & D.M. Dacey (2003) Circuitry of the parasol ganglion cell receptive field surround. Annual Meeting Abstract and Program Planner. Association for Research in Vision and Ophthalmology. E-Abstract 3236.

M.J. McMahon & D. Dacey (2002) Retina in a dish: visualizing neurons, presenting stimuli, and recording visual responses. Poster presented at the Univ. of Rochester Center for Visual Science 23rd Symposium: Engineering the Eye.

O.S. Packer, M.J. McMahon & D.M. Dacey (2002) Carbenoxolone blocks horizontal cell feedback and eliminates the ganglion cell surround in macaque monkey retina. Annual Meeting Abstract and Program Planner. Association for Research in Vision and Ophthalmology. E-Abstract 2922.

M.J. McMahon & D.I.A. MacLeod (2000) Visual resolution with obliquely incident light: Retinal contrast losses. Investigative Ophthalmology and Visual Sciences (Suppl.), 40, 4.

M.J. McMahon & D.I.A. MacLeod (1998) The oblique effect arises after the site of pattern adaptation and masking in humans. Investigative Ophthalmology and Visual Sciences (Suppl.), 39, 4.

M.J. McMahon (1996) Retinal receptive field structue: Experiments and models. Paper presented at the University of California Multicampus Research Group in Vision Modeling Annual Meeting, October 16, 1996.

M.J. McMahon, M.J.M. Lankheet, P. Lennie & D.R. Williams (1995) Fine structure of P-cell receptive fields in the fovea, revealed by laser interferometry. Investigative Ophthalmology and Visual Sciences (Suppl.), 36, 4.

M.J. McMahon & D.I.A. MacLeod (1994) Color blind color vision at high light levels: Red/green discrimination using the blue-sensitive cones. Investigative Ophthalmology and Visual Sciences (Suppl.), 35, 1572.

K. Knoblauch & M.J. McMahon (1993) A test of Maxwell's and Cornsweet's conjecture on the dimension of color discrimination of binocular color mixtures in dichromacy. Investigative Ophthalmology and Visual Sciences (Suppl.), 34, 748.

Invited Talks and Seminars

M.J. McMahon (2006) Visual Prosthetics. Dartmouth Summer Institute in Cognitive Neuroscience: Conscious and unconscious cognition and their interface with artificial devices.

M.J. McMahon (2006) Restoring vision in blind people with technology. IEEE Engineering in Medicine and Biology, Buenaventura chapter.

M.J. McMahon (2005) Basic research toward the development of a retinal prosthesis: Retinal physiology and patient testing. Alfred E. Mann Foundation for Scientific Research.

M.J. McMahon (2003) Web design for the color-blind. University of Washington AccessibleWeb User's Group seminar.

M.J. McMahon, B.B. Peterson, D.M. Dacey, P.D. Gamlin & F.R. Robinson (2002) Fireworks in the Retina: Photodynamic filling in vitro links morphology, physiology and central connections for macaque ganglion cells. FASEB Retinal Neurobiology and Visual Processing Summer Research Conference, Saxtons River, VT.

O.S. Packer, M.J. McMahon & D.M. Dacey (2002) Carbenoxolone blocks horizontal cell feedback and eliminates ganglion cell surrounds in macaque monkey retina. FASEB Retinal Neurobiology and Visual Processing Summer Research Conference, Saxtons River, VT.

M.J. McMahon (2002) Light capture by cone photoreceptors: a psychophysical study. University of Houston School of Optometry Periopsia Seminar Series.

M.J. McMahon (2001) Retinal contrast losses and visual resolution with obliquely incident light. Vision and Color Topical Meeting of the Optical Society of America, Irvine, CA.

M.J. McMahon (2001) Light capture by cone photoreceptors: a psychophysical study. University of Pennsylvania Vision Seminar.

M.J. McMahon (2000)  Why isn't vision perfect?  University of Minnesota Vision Science Colloquium.

M.J. McMahon (2000)  Testing the limits of spatial resolution.  NASA Ames Research Center Seminar.

D.R. Williams, M.J. McMahon, D. Brainard & R. Navarro (1994) Comparison of noninvasive measures of the optical quality of the eye. Vision Science and its Applications Topical Meeting of the Optical Society of America, Santa Fe, NM.

M.J. McMahon (1993) The human visual system: More than meets the eye. University of Texas at San Antonio Prefreshman Engineering Program.

Contact Matt McMahon Copyright 2004 © Matthew J. McMahon. All rights reserved. last modified 07/13/2006