Age-related macular degeneration (SMD) is a leading cause of blindness in the U.S. population over 60 years old. Drusen are universally present in SMD, but they are also present in over 30% of the population over 60. Since there is now a mode of treating choroidal neovascular membranes if caught early enough, it is crucial to find a means of identifying drusen patients at high risk so as to monitor them more closely. We propose to study retinal and visual function in patients with drusen to try to determine those parameters which may correlate with high risk of developing exudative maculopathy. Our preliminary study included 15 drusen patients with either only drusen bilaterally, a choroidal neovascular membrane in one eye, or a pigment epithelial detachment in one eye. We performed foveal dark adaptation, static perimetric measures of absolute thresholds, foveal flicker thresholds, ERG, and EOG in these patients. The results lead to the conclusion that retinal functon abnormalities are confined to the posterior pole, dark-adaptation is delayed in some patients, and threshold elevations may be representative of neural response compression rather than loss of retinal sensitivity. We propose a series of studies that employ image processing, laboratory psychophysical measures and retinal densitometry to evaluate retinal function changes in relation to drusen and other retinal pigment epithelial (RPE) abnormalities. We will employ image analysis techniques to measure density, size, and spatial distributions of drusen. We will employ a fundus camera stimulator to perform measures of visual thresholds and dark-adaptation in relation to drusen and RPE atrophy. We will perform measures of after-image detection latencies, flash-on-flash increment thresholds, increment threshold spectral sensitivity, the Westheimer effect, and Enoch's measure of the """"""""transient-like function"""""""" to test various hypotheses regarding retinal function abnormalities. We will perform laser interferometric measures of spatial contrast sensitivity, we will measure hyperacuity and measure increment thresholds for small targets to test various hypotheses regarding visual acuity loss.
