MACULAR SCATTER (GRID) LASER TREATMENT OF POORLY DEMARCATED SUBFOVEALCHOROIDAL NEOVASCULARIZATION IN AGE-RELATED MACULAR DEGENERATION - RESULTS OF A RANDOMIZED PILOT TRIAL

Objectives: To determine the effects of macular scatter (''grid'') las er photocoagulation compared with observation on the visual function o f eyes with subfoveal choroidal neovascularization (CNV) that has poor ly demarcated boundaries and to provide preliminary data for the evalu ation of the feasibility and design of a larger, definitive trial. Des ign: Randomized pilot clinical trial. Setting: Two tertiary care retin al referral practices. Patients: Symptomatic individuals with subfovea l CNV secondary to age-related macular degeneration in whom fluorescei n angiography showed occult CNV with poorly demarcated boundaries; cla ssic CNV was allowed but did not need to be present for entry into the study. Main Outcome Measure: Change in visual acuity from baseline to specified time periods. Results: Fifty-two eyes were assigned to obse rvation. Fifty-one eyes were assigned randomly to treatment consisting of macular scatter (''grid'') laser photocoagulation to the area of C NV. The treatment protocol for 8 of these eyes also included confluent laser photocoagulation to areas of classic CNV. The average visual ac uity decrease from baseline was greater in the treated than in the obs erved group. The difference between these groups was greatest within t he first year after study enrollment. At 24 months, slightly more than 40% of the eyes in each group had lost 6 or more lines of visual acui ty. Similar results were noted for the subgroup of eyes initially with angiographic features of occult CNV but no classic CNV. Conclusions: These short-term study results suggest that macular scatter (''grid'') laser treatment is not beneficial and is possibly harmful compared wi th observation for symptomatic subfoveal CNV with poorly demarcated bo undaries in age-related macular degeneration. With or without treatmen t, a significant proportion of these patients are at risk of severe vi sual loss within 2 years of seeking treatment, even when the eye initi ally has occult CNV and no classic CNV.