Long-term visual outcome of choroidal neovascularization in pathologic myopia: natural history and laser treatment

This retrospective study was designed to help clarify the visual prognosis during long-term follow-up (5-10 years) of myopic choroidal neovascularization (CNV) with and without laser treatment in a referral population.

A group of 50 consecutive non-treated eyes and a group of 50 consecutive treated eyes were selected retrospectively. Inclusion criteria were: fluorescein angiographic documentation of CNV not involving the center of the fovea, visual acuity (VA) > or = 20/200, age less than 60, onset of symptoms < or = 6 months and at least five years of follow-up. The mean decrease in VA in non-treated and treated eyes during the follow-up was analysed on the basis of subgroups with the same initial VA.

Considering both groups (100 eyes) at presentation, 89% of CNV spared the center of the fovea but were located in the foveolar area (< 200 microns) and only 11% were extrafoveal (> or = 200 microns). In the natural history group, after five years all CNV involved the center of the fovea and mean VA was 20/160. In the treated group, at the end of the five year follow-up and after one or more laser session, 64% of eyes had a dry scar and mean VA was 20/74. Nevertheless there was a very high rate of recurrences (72%) and at the end of follow-up 36% of treated eyes had a subfoveal recurrence with a mean decrease in VA to 20/154. The difference between the mean decrease in VA of the treated and non-treated groups was statistically significant at two years. At five years (100 eyes), the difference persisted only for eyes with initial VA better than > or = 20/40 (P < 0.05). At eight years (76 eyes) and ten years (24 eyes), this difference was no longer significant.

This study confirms that CNV accompanying degenerative myopia has an extremely poor prognosis. Nevertheless analysis of final VA in both groups suggests that eyes with high initial VA gain more from treatment.