The Effect of Unilateral Glaucoma on Eccentricity Mapping within the Human Visual Cortex V Borges1, H Danesh-Meyer2, J Black1, B Thompson1 |
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1Department of Optometry and Vision Science, The University of Auckland, New Zealand |
| There is evidence that the neurodegenerative effects of glaucoma are not restricted to the optic nerve but extend to the visual cortex. However, very little is known about the effects of glaucoma on visual cortex function. We used functional magnetic resonance imaging to investigate this question in 5 adult patients with unilateral primary open-angle glaucoma. We assessed whether regions of V1 and V2 with lost input from the glaucomatous eye had a greater response to input from the fellow eye than regions receiving input from both eyes. We also assessed whether there were differences in the retinotopic maps within V1 and V2 when patients viewed through their glaucomatous versus their fellow eye. We found no evidence for an increased response to the fellow eye in glaucoma-effected regions of the cortex; however, there was a pronounced loss of activation in both V1 and V2 when patients viewed through their glaucomatous eye. Despite this reduced activation, visual cortex responses were still evident for glaucomatous eye viewing and the eccentricity mapping of these responses was shifted towards the fovea relative to maps obtained under fellow eye viewing. These results indicate that glaucoma may influence eccentricity mapping within the visual cortex. |
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