High prevalence of myopia in Japanese patients with idiopathic focal subretinal neovascularization.

Purpose: To determine whether myopia is more prevalent in Japanese patients with idiopathic focal subretinal neovascularization (IFSN) than in normal control subjects.

Methods: Forty-seven eyes of 46 patients with an initial diagnosis of IFSN and 291 eyes of 291 controls were studied. Refractive errors were measured with an autorefractometer, and the spherical equivalent of the refractive error was used for the statistical analyses. All patients had undergone fluorescein angiography (FA) to confirm the presence of the choroidal neovascularization. In addition, indocyanine green angiography (ICGA) had been performed to determine whether chorioretinal atrophy and breaks of Bruch's membrane, which are consistent with myopic retinopathy, were present.

Results: The mean age of the patients in the control group was not significantly different from that of patients in the IFSN group. The mean spherical equivalent of the refractive errors was -2.62 +/- 2.70 diopters (D) in the control group and -5.24 +/- 3.41 D in the IFSN group (P = 0.00005). The incidence of high myopia was significantly higher in the IFSN group (41.3%) than in the control group (12.0%, P < 0.0001). FA and ICGA showed no chorioretinal atrophy and lacquer cracks, thus confirming that patients with myopic retinopathy were excluded from the IFSN group. During the mean follow-up period (44.7 months), myopic retinopathy did not develop in any of the eyes in the IFSN group.

Conclusion: Japanese patients with IFSN were highly myopic, suggesting that myopia may play a role in the development of choroidal neovascularization in IFSN patients.