Occult choroidal neovascularization: Influence on visual outcome in patients with age-related macular degeneration

Purpose. To determine whether the presence of occult choroidal neovascularization (CNV) influenced the anatomic and visual acuity outcomes in a randomized clinical trial using krypton red laser photocoagulation of juxtafoveal neovascular lesions in age-related macular degeneration (AMD). Methods. Baseline fluorescein angiograms obtained in centers between 1981 and 1987 participating in the Macular Photocoagulation Study (MPS) Age-Related Macular Degeneration Study - Krypton Laser (AMDS-K) were evaluated retrospectively at the MPS Fundus Photograph Reading Center by two senior graders independently (with open adjudication of any differences) from 1992 to 1994. They classified CNV as classic, occult or both, using criteria developed by the MPS Group two years after the AMDS-K recruitment was completed. Results. Classic CNV almost always was completely covered with intense laser treatment; nevertheless, recurrent CNV developed in more than half of these eyes within 1 year after initial treatment. In contrast, in more than half the eyes with a component of occult CNV with classic CNV only, over 50% of the occult CNV was not covered with heavy laser treatment. Laser treatment was clearly beneficial for eyes whose lesions were composed of classic CNV only; it was nearly equivalent to no treatment for eyes with both classic and occult CNV. Conclusions. These results strengthen previous reports that, despite recurrence, laser treatment benefits eyes with juxtafoveal choroidal neovascular lesions when classic CNV only is present. Treatment of classic CNV alone in eyes with both classic and occult CNV was not beneficial in this study. Distinguishing classic CNV from occult CNV can aid in selecting patients who will benefit most from laser treatment.