Abstract
Purpose: :
To investigate the influence of non-perfusion area (NPA) and macular ischemia on visual acuity (VA) gain at 1-year in branch retinal vein occlusion (BRVO), and to determine factors correlating with the 1-year VA gain.
Methods: :
The records of 231 patients with BRVO were retrospectively reviewed. They were classified into BRVO with or without non-perfusion area (NPA+ or -) and with or without macular ischemia (macular ischemia+ or -). NPA was defined as the presence of more than 5 disc areas of capillary non-perfusion, and macular ischemia as the presence of more than 120-degrees of foveal avascular zone enlargement with foveal capillary ring deficit. Visual acuity (VA) was converted into logarithm of the minimum angle of resolution (logMAR) for statistical analyses. To determine factors correlating with the 1-year VA gain, stepwise multivariate analysis was performed with sex, age, NPA, and macular ischemia.
Results: :
The eyes were classified into NPA+ (n=103) and NPA- (n=128); macular ischemia+ (n=71) and macular ischemia- (n=160). The baseline VA of NPA+ was lower than that of NPA- (logMAR= 0.49 vs 0.34, p=0.002; t-test), but there was no significant difference in the 1-year VA (0.32 vs 0.26, p=0.213; t-test). The 1-year VA gain of NPA+ was significantly greater than that of NPA- (0.18 vs 0.08, p=0.0264; t-test). Macular ischemia was not correlated with NPA (p=0.152, chi-square test). Stepwise multivariate analysis revealed that factors associated with poorer VA gain include better baseline VA, older age and presence of macular ischemia. NPA was not found to be a significant factor for the VA gain in stepwise multivariate analysis. Discrepancy of the significance between the t-test and stepwise multivariate analysis about NPA as a prognostic factor may be because NPA correlates with the baseline VA and the baseline VA may have a greater influence on VA gain.
Conclusions: :
NPA was not a prognostic factor for visual gain in BRVO and, at least, does not relate to a poor VA gain. Better baseline VA, older age, and macular ischemia were the major factors associated with poorer visual gain in BRVO.