Influence of unilateral intravitreal bevacizumab injection on the incidence of symptomatic choroidal neovascularization in the fellow eye in patients with neovascular age-related macular degeneration (Review)

Neovascular age-related macular degeneration (neovascular ARMD) represents only 10% of ARMD cases but is responsible, if untreated, for quick and severe central vision loss due to major macular changes. The presence of choroidal neovascularization (CNV) in one eye is associated with an approximately 10% risk of CNV development in the fellow eye each year. Intravitreal anti-VEGF therapy has quickly evolved as the standard treatment in neovascular ARMD in the last decade due to significant anatomical and functional improvements, especially in the early stages. In many reports an improvement in the untreated fellow eye was mentioned and systemic exposure was soon confirmed for all anti-VEGF agents after unilateral intravitreal injection. In particular, bevacizumab intravitreal injection is followed by a consistent reduction of serum VEGF levels and the drug was shown to have the longest serum half-life raising important debates about its safety. Once bevacizumab was detected in the fellow eye of an animal model after unilateral injection, the possible influence on fellow eye conversion rate into neovascular ARMD was questioned. Although comparative studies have not found statistically significant differences between drugs regarding the incidence of symptomatic CNV in the fellow eye during treatment, we observed, on a retrospective 36-month evaluation, a reduced incidence of symptomatic CNV in the fellow eye that might be explained by the consistent systemic exposure of bevacizumab.