Optic Nerve Head Biomechanic and IOP Changes Before and After the Injection of Aflibercept for Neovascular Age-Related Macular Degeneration

Purpose: We investigated the early effects of intravitreal aflibercept injection (IAI) on optic nerve head (ONH) morphology. Methods: All of the participants underwent applanation tonometry and enhanced depth imaging by spectral-domain optical coherence tomography immediately before injection, and within 5 and 30 minutes after IAI. Changes in the anterior lamina cribrosa surface depth, prelaminar tissue thickness (PTT), optic cup width, optic cup depth, and Bruch's membrane opening (BMO) were assessed. Results: The study included 30 eyes of 30 subjects with a mean age of 77.4 ± 6.8 years (range, 65-89 years) following IAI (2 mg in 0.05 ml). Within 5 minutes after injection, the mean cup depth, mean cup width, and BMO were significantly increased (P = 0.013, P = 0.000, and P = 0.004, respectively), whereas the mean PTT was thinned (P = 0.009). These morphologic changes returned to near baseline values 30 minutes after injection. Cup widening and BMO expansion (P = 0.000; r, 0.668), as well as cup deepening and prelaminar thinning (P = 0.000; r, -0.838), were significantly correlated. The magnitude of cup deepening and prelaminar tissue thinning correlated with the IOP change in the opposite direction than expected (P = 0.039; r, -0.379 and P = 0.377; r, 0.040). Conclusions: A significant widening and deepening of the optic cup, BMO expansion, and prelaminar tissue thinning occurred following IAI for neovascular AMD. Eyes having greater optic disc cup deepening and prelaminar tissue condensation after IAI, associated with a lower IOP increase after injection, suggesting that ONH compliance might buffer the effect of additional intravitreal fluid injection on IOP values.