May 2008
Volume 49, Issue 13
Free
ARVO Annual Meeting Abstract  |   May 2008
Psychophysical Magnocellular and Parvocelluar Contrast Gain in Patients With Optic Neuritis
Author Affiliations & Notes
  • D. Cao
    Ophthalmology and Visual Science, University of Chicago, Chicago, Illinois
  • A. J. Zele
    School of Optometry, Queensland University of Technology, Brisbane, Australia
  • J. Pokorny
    Ophthalmology and Visual Science, University of Chicago, Chicago, Illinois
  • S. M. Ksiazek
    Ophthalmology and Visual Science, University of Chicago, Chicago, Illinois
  • D. Lee
    Illinois College of Optometry, Chicago, Illinois
  • L. V. Messner
    Illinois College of Optometry, Chicago, Illinois
  • N. Chaudhary
    Illinois College of Optometry, Chicago, Illinois
  • J. W. Nicholas
    Ophthalmology and Visual Science, University of Chicago, Chicago, Illinois
  • Footnotes
    Commercial Relationships  D. Cao, None; A.J. Zele, None; J. Pokorny, None; S.M. Ksiazek, None; D. Lee, None; L.V. Messner, None; N. Chaudhary, None; J.W. Nicholas, None.
  • Footnotes
    Support  NIH Grant EY00901
Investigative Ophthalmology & Visual Science May 2008, Vol.49, 1193. doi:https://doi.org/
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      D. Cao, A. J. Zele, J. Pokorny, S. M. Ksiazek, D. Lee, L. V. Messner, N. Chaudhary, J. W. Nicholas; Psychophysical Magnocellular and Parvocelluar Contrast Gain in Patients With Optic Neuritis. Invest. Ophthalmol. Vis. Sci. 2008;49(13):1193. doi: https://doi.org/.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract

Purpose: : To evaluate contrast threshold deficits in patients with optic neuritis under conditions designed to favor mediation by either the inferred Magnocellular (MC) or Parvocelluar (PC) pathway.

Methods: : Luminance contrast discrimination was measured in 9 patients with unilateral or bilateral optic neuritis and 4 age-matched controls with normal vision, using steady- and pulsed-pedestal paradigms (Pokorny & Smith, JOSA A 14: 2477-2486, 1997) to bias performance toward the MC or PC pathway respectively. Additionally, L-M chromatic discrimination at equiluminance was evaluated using the steady-pedestal paradigm. The measured data were fitted by a physiologically plausible model that included parameters accounting for contrast gain and contrast sensitivity in the inferred MC or PC pathway. The fitted parameters from the affected eye were compared with those from the clinically non-affected eye in patients with unilateral optic neuritis, or with those from the controls.

Results: : For all affected eyes, the pulsed-pedestal data indicated a large decrease in PC contrast gain and contrast sensitivity. Interpretation of the steady-pedestal data was not clear-cut. There was a significant loss of sensitivity but it is uncertain whether detection under these conditions was mediated by the MC or PC pathway. We are certain that the loss of MC contrast gain was at least as great, or greater than the loss of PC contrast gain. In patients with unilateral optic neuritis, the contrast gain and contrast sensitivity in the affected eyes showed significant losses compared with the non-affected eyes. However, the non-affected eyes were not completely normal; they showed significantly lower contrast gain and sensitivity compared with the controls.

Conclusions: : Optic neuritis produced large contrast gain and sensitivity losses for both inferred PC and MC mediated thresholds, suggesting that the disease in the optic nerve limits the information transfer from retina to cortex.

Keywords: contrast sensitivity • optic nerve • discrimination 
×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×