Objective: This study was aimed at localizing and quantifying retinal defects in patients with branch retinal vein occlusion by means of scanning laser perimetry and analyzing the mechanism involved in the functional recovery after laser therapy.
Design: Prospective nonrandomized clinical trial with concurrent comparison group.
Participants: Fifty-eight patients with isolated branch retinal vein occlusion. Thirty-nine eyes received laser treatment; 19 eyes were observed without treatment.
Intervention: Argon laser photocoagulation was performed according to the Branch Vein Occlusion Study recommendations.
Main outcome measures: Retinal functional deficits were evaluated with scanning laser perimetry and fluorescein angiography first at baseline, at 3-month follow-up visits and 3 months after laser treatment.
Results: After laser treatment, the scotoma encroached on foveal fixation in 31% of eyes, remained stable in 36%, and regressed from the foveal avascular zone in 33%. Improvement in vision was correlated with increasing scotoma distance from fixation. Total scotoma size increased in 50% of eyes after treatment. Depth of scotoma and degree of angiographic leakage showed no direct correlation.
Conclusions: Stabilization and increase in visual acuity after laser treatment did not correlate with an overall decrease in scotoma size. Improved central visual function seen in 25% of treated eyes appeared to be due to withdrawal of scotoma from the fovea.