Significance of refractive status in branch retinal vein occlusion. A case-control study.

PURPOSE: To evaluate the significance of refractive error in cases of branch retinal vein occlusion.

METHODS: Of 354 patients with branch retinal vein occlusion who attended our clinic between 1989 and 1995, 75 patients with unilateral branch retinal vein occlusion were compared with an equal number of matched controls with similar inclusion and exclusion criteria. The spherical equivalents of the refractive errors of patients in both groups were compared using the chi-square test, student's t test, and multivariate logistic regression.

RESULTS: Hypermetropia was present in 53 patients with branch retinal vein occlusion (70.7%) and in 33 control patients (44.0%; P = 0.0001). Myopia was present in 11 patients with branch retinal vein occlusion (14.7%) and in 30 controls (40.0%; P = 0.0005). Emmetropia was present in 11 patients with branch retinal vein occlusion (14.7%) and in 12 controls (16.0%; P = 0.820). The odds ratio of developing branch retinal vein occlusion among patients with hypermetropia was 3.42 (95% Confidence Interval [CI], 1.62-7.2; P = 0.001) when compared with patients with no hypermetropia and 5.3 (95% CI, 2.1-13.3; P = 0.0003) when compared with patients with myopia alone.

CONCLUSION: Hypermetropia is significantly more common in patients with branch retinal vein occlusion than in the general population, whereas myopia is significantly less common in these patients.