# Simultaneous bilateral intravitreal anti-vascular endothelial growth factor injections from one vial for diabetic macular edema: a retrospective analysis

## TL;DR

This study shows that injecting anti-VEGF drugs into both eyes at once from one vial is safe and effective for treating diabetic macular edema.

## Contribution

Demonstrates the safety and efficacy of simultaneous bilateral anti-VEGF injections from a single vial for DME treatment.

## Key findings

- Both bilateral and unilateral injection groups showed significant improvements in visual acuity and retinal thickness.
- Bilateral injections resulted in greater visual acuity improvement and greater reduction in retinal thickness compared to unilateral injections.
- No severe complications were observed in either group.

## Abstract

The objective of this study was to assess the safety and efficacy of simultaneous bilateral intravitreal injections of anti-vascular endothelial growth factors (anti-VEGF) from a single vial for the treatment of diabetic macular edema (DME).

A retrospective case series study was undertaken. The study population comprised patients who underwent intravitreal anti-vascular endothelial growth factor injections for DME at the Ophthalmology department of Zhejiang Hospital between January 2022 and May 2024. Participants were categorized into bilateral (n = 34, 102 injections) and unilateral (n = 93, 210 injections) groups. The primary outcome measures were best corrected visual acuity (BCVA) and central subfield thickness (CST), cube average thickness (CAT) along with the incidence of severe clinical complications. Statistical analysis was performed using the Mann-Whitney U test and Wilcoxon rank sum test.

There were no statistically significant differences in terms of age, gender, hypertension, years of diabetes, disorganization of the inner retinal layers (DRIL), ellipsoid zone (EZ) grade, BCVA, CST or CAT at baseline between the two groups. Both bilateral and unilateral injection groups demonstrated significant enhancements in BCVA at 1 month post-injection (P < 0.001; P < 0.001). A substantial decrease in CST and CAT were observed in both groups at 1 month post-injection (P < 0.001; P < 0.001; P < 0.000; P < 0.000). The median improvement in BCVA at 1 month post-injection relative to pre-injection was 8.0 letters (IQR: 3.0–19.0) in the bilateral injection group and 5.5 letters (IQR: 1.0–13.0) in the unilateral injection group, with a statistically significant difference between the two groups (P = 0.009). The reduction in CAT demonstrated significant difference between the two groups (P < 0.001). No severe complications, including cataract, retinal detachment, choroidal detachment, vitreous hemorrhage, or endophthalmitis, were reported in any of the patients.

Simultaneous bilateral anti-VEGF injections from a single vial are both safe and efficacious for the treatment of DME, thereby reducing the treatment burden, visit times and costs while enhancing patient compliance.