VISUAL FUNCTION ABNORMALITIES AND PROGNOSIS IN EYES WITH AGE-RELATED GEOGRAPHIC ATROPHY OF THE MACULA AND GOOD VISUAL-ACUITY

Purpose: Geographic atrophy (GA) may cause significant compromise of v isual function, even when there still is good visual acuity (VA), beca use of parafoveal scotomas and foveal function abnormalities antedatin g visible atrophy. This study evaluates the visual function abnormalit ies at baseline and the 2-year worsening of VA and reading rate for ey es with GA compared with a group of eyes with drusen only. Methods: Se venty-four eyes with GA and VA greater than or equal to 20/50 from a p rospective natural history study of GA were included, as were 13 eyes with only drusen. Baseline visual function testing and 2-year VA and m aximum reading rate are reported. Results: The worsening of VA in decr eased luminance and foveal dark-adapted sensitivity showed severe abno rmalities for the GA group. Contrast sensitivity was significantly red uced for the eyes with GA. Half the eyes with GA, but none of the drus en eyes, had maximum reading rates below 100 words per minute. A scann ing laser ophthalmoscope (SLO) measure of the scotoma near fixation co mbined with a measure of residual foveal function accounted for 54% of the variability in maximum reading rate in the eyes with GA. Of 40 ey es with GA observed for 2 years, half lost greater than or equal to 3 lines of VA and one quarter lost greater than or equal to 6 lines. The nine eyes with drusen with follow-up had no significant change in VA. Low foveal dark-adapted sensitivity, SLO measures of the scotoma with in 1 degrees of fixation, and low maximum reading rate were statistica lly significant risk factors for doubling of the visual angle. Signifi cant reduction in maximum reading rates at 2 years was present for the eyes with GA. Conclusions: The eyes with GA with good VA have profoun d decreases in visual function, particularly in dim lighting and in re ading. Half the eyes with GA had doubling in visual angle at 2 years a fter the baseline examination, whereas the drusen eyes remained essent ially unchanged. Impaired visual function at baseline was predictive o f an adverse outcome for the eyes with GA.