RETINAL PATHOLOGY IN ALZHEIMERS-DISEASE .1. GANGLION-CELL LOSS IN FOVEAL PARAFOVEAL RETINA/

Morphometric analysis of the numbers of neurons in the ganglion cell l ayer (GCL) of the central retina (fovea/foveola/parafoveal retina) in eyes from 9 Alzheimer's disease (AD) and 11 age-marched control cases revealed an overall decrease of 25% in total numbers of neurons in AD as compared with control eyes. Detailed analyses of GCL neurons at var ious eccentricities from the foveola showed that the greatest decrease in neuronal density (43% decrease) occurred in the central 0-0.5 mm ( foveal region), while at 0.5-1 mm and at 1-1.5 mm eccentricities, neur onal loss amounted to 24 and 26%, respectively. The temporal region of the central retina appeared most severely affected, with up to 52% de crease in neuronal density near the foveola (central 0-0.5 mm eccentri city). There was close agreement between fellow eyes analyzed separate ly for three AD and three control cases. Analysis of neuronal sizes sh owed that all sizes of neurons were similarly affected in AD. In the G CL of control retinas, neurons decreased with age (coefficient of corr elation = -0.67), while in AD retinas no such relationship was evident . Since in the central 0-2 mm region of the retina 97% of neurons in t he GCL are ganglion cells (while the remaining 3% consist of displaced amacrine cells), these results demonstrate extensive ganglion cell lo ss in the central retina in AD.