Combined subfoveal choroidal neovascular membranes: Clinical and histopathologic features

Purpose. Combined subfoveal choroidal neovascular membranes consist of a double layer membrane extending both into the subretinal and the sub-RPE space. The purpose of the current study was to determine whether characteristic clinical findings exist that distinguish such membranes and to evaluate the outcome after surgical excision. Methods. We examined six consecutive combined membranes by light microscopy and evaluated the pre- and postoperative clinical course of the patients including fundus photographs and fluorescein angiograms. Mean follow-up was 9.1 months after surgery. Results. All patients with combined subfoveal membranes had age-related macular degeneration. Three patients had surgical excision of the subfoveal membranes after recurrences developed following laser treatment. By fluorescein angiography and clinical characteristics, none of the six patients were distinguishable from patients with single layer membranes. Histopathologically, significant amounts of proliferated RPE cells were present in the excised membranes. The most common finding on postoperative angiograms was a window defect. The visual acuity improved in two patients (up to 20/60 and 20/125), remained stationary in three patients and became worse following recurrence of the membrane in the remaining patient. Conclusions. In our series, combined subfoveal membranes could not be identified based on preoperative clinical and angiographic findings. Despite the extent of these membranes, vision stabilized after surgery.