Visual acuity and multifocal electroretinographic changes after arteriovenous crossing sheathotomy for macular edema associated with branch retinal vein occlusion

Abstract

Purpose: To evaluate the influence of arteriovenous (AV) sheathotomy on retinal function with central multifocal electroretinography (mfERG) in eyes with macular edema secondary to branch retinal vein occlusion (BRVO).

Methods: Fifteen patients (15 eyes) who underwent AV sheathotomy for macular edema secondary to BRVO were included in the study. Best-corrected visual acuity and mfERG responses from the most central seven hexagons were analyzed before and 6 months after the operation.

Results: The mean preoperative Early Treatment Diabetic Retinopathy Study (ETDRS) score +/- SD was 34.1 +/- 12.7 letters (Snellen equivalent, 20/50) and significantly improved up to 40.5 +/- 10.9 letters (Snellen equivalent, 20/40) at 6 months after AV sheathotomy (P = 0.027, Wilcoxon signed rank test). The mean preoperative P1 amplitude +/- SD of the most central 7 hexagons was 39.30 +/- 10.86 nV/deg(2) for the affected eye versus 47.72 +/- 6.67 nV/deg(2) for the normal fellow (control) eye (P = 0.013, Mann-Whitney U test) and significantly increased up to 50.71 +/- 15.58 nV/deg at 6 months after the operation (P = 0.014, Wilcoxon signed rank test). Significant correlations between preoperative and postoperative ETDRS score and preoperative P1 amplitude were present (r = 0.929, P < 0.001; r = 0.768, P = 0.001; respectively [Spearman correlation]).

Conclusions: AV sheathotomy improved macular function and anatomical outcome as measured by ETDRS score and mfERG responses in patients with macular edema due to BRVO.

Fig. 1

Trace arrays and topographic representations before (A and C, respectively) and 6 months after (B and D, respectively) surgery. Note the increase in P1 amplitudes of the central area. The Early Treatment Diabetic Retinopathy Study score for the patient improved from 14 letters to 38 letters.

Fig. 2

Scattergram demonstrating the relation between preoperative Early Treatment Diabetic Retinopathy Study (ETDRS) scores and preoperative multifocal electroretinography P1 amplitudes (r = 0.929, P < 0.001, Spearman correlation). The Spearman correlation value shows that the preoperative ETDRS scores significantly related to the P1 amplitudes.

Fig. 3

Scattergram demonstrating the relation between preoperative multifocal electroretinography P1 amplitudes and end point Early Treatment Diabetic Retinopathy Study (ETDRS) scores (r = 0.768, P = 0.001, Spearman correlation). The Spearman correlation value shows that the preoperative P1 amplitudes significantly related to the postoperative ETDRS scores.