Visual outcome after laser photocoagulation for subfoveal choroidal neovascularization secondary to age-related macular degeneration. The influence of initial lesion size and initial visual acuity. Macular Photocoagulation Study Group.

OBJECTIVE: To provide detailed information specific to the initial visual acuity and initial lesion size on the outcome of patients with subfoveal choroidal neovascularization (CNV) secondary to age-related macular degeneration.

DESIGN AND PATIENTS: The 189 eyes assigned to laser photocoagulation and the 184 eyes assigned to observation in the Subfoveal New CNV Study were divided into nine subgroups based on initial visual acuity and initial lesion size.

MAIN OUTCOME MEASURES: The pattern of visual acuity loss for both treated and untreated eyes through 4 years of follow-up was compared among the subgroups. Reading speed and contrast thresholds also were examined.

RESULTS: Four patterns (A, B, C, D) of visual acuity loss in treated eyes relative to untreated eyes were identified. Eyes in group A (small lesion and moderate or poor initial visual acuity or medium lesion and poor visual acuity) had the best visual outcome with treatment; treated eyes were better throughout follow-up. Eyes in group B (small lesion and good initial visual acuity or medium lesion and moderate or good visual acuity) had substantial treatment benefit by 12 months, but were worse immediately after treatment. Eyes in group C (large lesion and poor initial visual acuity) had a small treatment benefit throughout follow-up. Eyes in group D (large lesion and moderate or good visual acuity) had the worst visual outcome with treatment; treated eyes were substantially worse for the first 18 months and were not appreciably better through 4 years of follow-up.

CONCLUSIONS: Recommendations for treatment of subfoveal CNV should take account of the initial visual acuity and lesion size. Eyes in group D are poor candidates for laser treatment.