Bevacizumab versus Dexamethasone Implant Followed by Bevacizumab for the Treatment of Macula Edema Associated with Branch Retinal Vein Occlusion

Abstract

Purpose: To compare visual and anatomical outcomes of intravitreal injections of bevacizumab and dexamethasone implant (Ozurdex) treatment for macular edema associated with branch retinal vein occlusion (BRVO).

Methods: We retrospectively reviewed patients who underwent intravitreal bevacizumab administered monthly on a pro re nata (PRN) basis (26 eyes, IVB group) or an initial 700-μg dexamethasone implant followed by a bevacizumab PRN injection (20 eyes, IVD group) for treatment of macular edema associated with BRVO. We compared best-corrected visual acuity (BCVA) and central macular thickness (CMT). We also measured ellipsoid zone recovery rate and ganglion cell-inner plexiform layer volume within the center 6 mm zone. A linear mixed model analysis was performed to compare serial changes in BCVA and CMT.

Results: Both groups showed significant improvement in BCVA and significant reduction in CMT. However, BCVA in the first month was significantly better in the IVD group (logarithm of the minimum angle of resolution, IVD group 0.21 ± 0.26 vs. IVB group 0.39 ± 0.30, p = 0.038) and the 1-month CMT was thinner in the IVD group (IVD group 270.0 ± 62.0 μm vs. IVB group 338.9 ± 122.6 μm, p = 0.028), and these trends were maintained during the 6-month follow-up. The IVD group showed more rapid macular edema resolution (p = 0.049); however, there were no significant differences in ellipsoid zone recovery rate (p = 0.268) or ganglion cell-inner plexiform layer volume between the two groups (p = 0.459).

Conclusions: There were no significant differences in final visual or anatomical outcomes between the two groups; however, initial dexamethasone implant injection followed by bevacizumab PRN injection initially showed more rapid improvement in vision and BRVO-associated macular edema resolution compared to intravitreal bevacizumab administered monthly on a PRN basis.

Keywords: Bevacizumab; Dexamethasone; Macular edema; Retinal vein occlusion.

Fig. 1. Macular thickness and ganglion cell-inner plexiform layer complex (GCIPL) analysis (A) Macular thickness analysis. We measured center 1-mm average macular thickness (number 1), average macular thickness of edematous side of inner ring of Early Treatment Diabetic Retinopathy Study (ETDRS) grid (number 2), and average macular thickness of edematous side of outer ring of ETDRS grid (number 3). (B) GCIPL volume of 6-mm ETDRS grid were calculated. Area between yellow and purple line is ganglion cell (GC) and area between purple and red line is inner plexiform layer (IPL). GCIPL volume was calculated by adding the volume of GC and IPL.

Fig. 2. Comparison of serial changes of (A) best-corrected visual acuity (BCVA) and (B) center, (C) inner ring, and (D) outer ring macular thickness. between bevacizumab and dexamethasone implant treatment groups and the results of linear mixed model analysis. Tables underlying the graphs represent the results of linear mixed modeling, which was performed three times, overall, during the first month after first injection and between 1 and 6 months after first injection (group and time were fixed effects, patient identification number was a categorical random effect). Significant group and time interaction (group × time) imply different rates of change between the groups. Coef. = β coefficient.

Fig. 3. Comparison of macular edema resolution and ellipsoid zone recovery rate between bevacizumab and dexamethasone implant treatment groups. (A) Macular edema resolution rate. Dexamethasone group showed significantly rapid resolution of macular edema (p = 0.049, log-rank test). (B) Ellipsoid zone recovery rate. There were no significant differences in ellipsoid zone recovery rate between two groups (p = 0.373, log-rank test).