# Efficacy of high-dose vs. low-dose intravitreal ganciclovir for cytomegalovirus retinitis: a systematic review and meta-analysis

## TL;DR

This study compares high-dose and low-dose intravitreal ganciclovir for treating CMV retinitis and finds higher doses improve retinitis resolution.

## Contribution

The study provides evidence that high-dose intravitreal ganciclovir improves anatomical resolution of CMV retinitis compared to low doses.

## Key findings

- High-dose regimens achieved significantly higher retinitis resolution (94%) compared to low-dose regimens (73%).
- Visual outcomes and recurrence rates did not differ significantly between high and low doses.
- Retinal detachment rates were similar across both dose groups.

## Abstract

Intravitreal ganciclovir is widely used to achieve effective local antiviral concentrations for cytomegalovirus (CMV) retinitis; however, to our knowledge, standardized dosing strategies have not been established, and the reported regimens vary considerably across studies. In this study, we evaluated dose-dependent treatment outcomes of intravitreal ganciclovir for CMV retinitis.

The PubMed, Embase, Cochrane Library, and Scopus databases were searched through November 2025. Eligible studies included intravitreal ganciclovir monotherapy, with or without systemic antiviral therapy. Cumulative first-week intravitreal dose was calculated and classified as low dose (<4,000 µg) or high dose (≥4,000 µg). The pooled proportions for resolution, visual outcomes, recurrence, and retinal detachment were estimated using a random-effects model.

Eighteen studies comprising 1132 eyes were included across all outcomes. The pooled proportion of anatomical resolution was 89% (95% confidence interval, 0.77–0.95), and 74% of eyes maintained stable or improved vision. Recurrence and retinal detachment occurred in 12% and 9% of the eyes, respectively. High-dose regimens achieved a significantly higher resolution than low-dose regimens (94% vs. 73%, p=0.019). Visual outcomes did not differ according to dose (77% vs. 73%, p=0.646). Recurrence also showed no dose-dependent difference (14% vs. 8%, p=0.654) and was observed predominantly in patients before the introduction of highly active antiretroviral therapy. The retinal detachment rates were similar (9% vs. 10%, p=0.780).

Initial intravitreal dosing at ≥4,000 µg within the first week achieved better retinitis resolution, supporting the benefit of a higher local ganciclovir concentration in the treatment of CMV retinitis.