Second eye involvement in age-related macular degeneration: a four-year prospective study.

Age-related macular degeneration (AMD) usually affects both eyes over time. Among patients with advanced AMD in one eye estimates of the risk to the second eye have been diversely reported. Therefore we examined, over a four year period, the rate of second eye involvement in 41 patients with either exudative or advanced atrophic AMD in one eye, and early macular changes in the second eye with best corrected vision of 20/30 or better. The cumulative risk of developing either exudative AMD or atrophic AMD and 20/80 or less vision in the second eye was 23% at four years. The cumulative risk of losing 10 or more letters on the ETDRS visual acuity chart in the second eye was 35% at four years. These results are discussed in relation to previously reported rates of second eye involvement in AMD.