Assessment of anti-VEGF intravitreal injection effects on murine neonatal Schlemm's canal morphology

Anti-VEGF intravitreal injections are the standard treatment for retinopathy of prematurity (ROP). Schlemm's canal, essential for regulating the conventional aqueous humor outflow pathway, is still in development in premature infants. Anti-VEGF injections in premature infants may negatively impact Schlemm's canal development, potentially increasing glaucoma risk. We sought to determine the effects of anti-VEGF intravitreal injections on Schlemm's canal morphology in neonatal mice. We therefore assessed Schlemm's canal morphology following anti-VEGF intravitreal injections in neonatal mice subjected to the oxygen-induced retinopathy (OIR) model with features of ROP. Intraocular pressure (IOP) was measured 5 days following injections, and ex vivo analyses of retinal flatmounts and anterior eye cups were performed to assess retinal vasculature (isolectin B4) and Schlemm's canal morphology (CD31). Intravitreal injections of anti-VEGF antibody reduced both retinal vascular and avascular areas in OIR retinas compared to control. However, anti-VEGF injections did not induce changes in Schlemm's canal morphology or sustained changes in IOP. Our findings indicate that a single intravitreal injection of anti-VEGF does not significantly affect murine Schlemm's canal morphology or IOP. If anti-VEGF intravitreal injections predispose infants to glaucoma later in life, these results suggest it is unlikely due to direct effects on Schlemm's canal morphology during development.