Recurrent subretinal neovascularization.

A retrospective analysis of a consecutive series of patients treated with krypton red laser (KRL) photocoagulation for subretinal neovascularization (SRN) secondary to drusen-related macular degeneration (DMD) was carried out to investigate the frequency and nature of recurrent neovascularization (recurrence). A classification of various types of recurrences based on the clinical and fluorescein angiographic features and the onset of their appearance in the postoperative course was used in this study. Patient, fundus, and membrane variables were examined in search of relevant high risk factors predisposing to recurrences. The membrane's proximity to the fovea and its relative lack of pigmentation were individual factors which were associated with a high risk of recurrence (P less than 0.05 for distance and P = 0.005 for color). Multivariate analysis also indicated that a greater distance from the fovea (P less than 0.05) and a darker color (P = 0.002) were favorable features to the primary membrane, reducing the probability of a recurrence. Overall, 39% of the patients experienced recurrences (23% of the patients had treatable recurrences and 16% had non-treatable recurrences extending under the center of the fovea). The membranes recurred predominantly at the margin of the photocoagulation burn. The recurrences were also noted relatively early in the postoperative course, 65% within two months after photocoagulation of the primary membrane. The fluorescein angiographic and clinical nature of these membranes and the visual effect of retreatment are also discussed in the paper.