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

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).

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.

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).

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.