Purpose: To examine an association between high myopia and diabetic retinopathy (DR) in diabetic patients with high myopic anisometropia.
Methods: A total of 116 white diabetic patients (232 eyes) with high myopia (spherical equivalent > -5.00 diopters, D) anisometropia (difference ≥ -6 D) were enrolled in this cross-sectional, contralateral eye study. The frequency of DR was compared between the high myopic and the contralateral eyes.
Results: Compared with the fellow eyes, DR was significantly less frequent in high myopic side (27.6% vs. 100%, P < 0.001; relative risk, 0.28 with 95% confidence interval of 0.21-0.37). Similar significant trends were found for the incidence of nonproliferative (27.6% vs. 69%, P < 0.001) and proliferative DR (0% vs. 31%, P < 0.001). Diabetic retinopathy was also less severe in the same group.
Conclusion: Using a contralateral eye study design prevented the influence of potential confounding factors inherent in similar previous case-control studies. On this basis, a protective role for high myopia against DR was established.