Atrophic macular degeneration. Rate of spread of geographic atrophy and visual loss

The authors studied 50 eyes with atrophic (dry) macular degeneration (geographic atrophy of age-related macular degeneration [GAMD], in 50 consecutive patients for 2 to 6 years (average, 3.4 years). There were 35 women and 15 men ranging in age from 60 to 89 years (average, 73 years). The areas of atrophy tended to follow the disappearance or flattening of soft drusen, pigment epithelial detachment, or reticular mottling of the retinal pigment epithelium. The atrophic areas were multifocal in 20 of the 50 eyes. Atrophy of the retinal pigment epithelium was followed by atrophy of the choriocapillaris. The atrophic areas tended to expand (average rate in one direction, 139 microns per year) and cause gradual loss of central visual acuity. The rate of significant visual loss (from 20/50 or better to 20/100 or worse) was 8% of eyes per year. There was a tendency toward resistance of the spread of atrophy into the fovea. The atrophy tended to expand faster in patients under age 75 and slower in patients aged 75 and over. Subretinal neovascularization developed in ten of the 50 eyes.