Changes in Scleral Thickness Following Repeated Anti-vascular Endothelial Growth Factor Injections

Abstract

Purpose: This cross-sectional study aimed to compare changes in scleral thickness between eyes injected with repeated anti-vascular endothelial growth factor (anti-VEGF) drugs and fellow injection naive eyes using optical coherence tomography (OCT). Methods: A total of 79 patients treated with three intravitreal anti-VEGF injections in one eye versus no injections in the fellow eye were included. Anterior segment- OCT measured scleral thickness in the inferotemporal quadrant 4 mm away from the limbus. Results: Injected eyes had a mean scleral thickness of 588 ± 95 μm versus 618 ± 85 μm in fellow naïve eyes (P < 0.001). Comparing injected eyes to fellow naïve eyes stratified by injection number showed a mean scleral thickness of 585 ± 93 μm versus 615 ± 83 μm in eyes with 3–10 injections (n = 32, P = 0.042); 606 ± 90 μm versus 636 ± 79 μm in eyes with 11–20 injections (n = 24, P = 0.017); and 573 ± 104 μm versus 604 ± 93 μm in eyes with >20 injections (n = 23, P = 0.041). There was no significant correlation between injection number and scleral thickness change (r = –0.07, P = 0.26). When stratified by indication, subjects with retinal vein occlusions showed a statistically significant difference in scleral thickness between injected and fellow naïve eyes (535 ± 94 μm and 598 ± 101 μm, respectively, P = 0.001). Conclusion: Compared to injection naive eyes, multiple intravitreal injections at the repeated scleral quadrant results in scleral thinning. Consideration of multiple injection sites should be considered to avoid these changes.