Corneal Endothelial Cell Changes Associated with Multiple Intravitreal Injections.

Purpose: To explore the changes in the corneal endothelium in patients who receive multiple anti-vascular endothelial growth factor (anti-VEGF) or steroid injections for posterior segment pathology.

Methods: This cross-sectional study recruits subjects treated with intravitreal anti-VEGF or sustained-release dexamethasone for macular edema due to retinal vein occlusion. Corneal endothelium and corneal thickness were measured in the treated eye using a corneal endothelial microscope. The study variables include age, endothelial cell density (ECD), coefficient of variation (CV) of cell size, percentage of hexagonality (HEX%), and intraocular pressure (IOP) change 30 min after injection. These variables were analyzed using multiple linear regression analysis.

Results: A total of 108 diseased eyes were treated with a variable number (from 4 to 28) of intravitreal injections between January 2020 and December 2023. The mean total number of intravitreal injections was 12.8/eye. Multiple linear regression analysis showed an inverse relationship between ECD and age (β = -9.74, 95% confidence interval [CI] [-8.01, -10.24], P < 0.05) and total number of injections (β = -17.11, 95% CI [-16.44, -18.37], P < 0.05). An inversion relationship also exists between HEX% and age (β = -0.17, 95% CI [-0.11, -0.23], P < 0.05) and total number of injections (β = -0.45, 95% CI [-0.37, -0.54], P < 0.05). A direct relationship exists between CV and age (β =0.29, 95% CI [0.19, 0.40], P < 0.05) and total number of injections (β =0.54, 95% CI [0.45, 0.63], P < 0.05). The mean IOP difference between the injected and contralateral eye 30 min postinjection was +6.4 ± 3 mmHg (P < 0.05).

Conclusion: A greater number of intravitreal injections is associated with a lower ECD, lower HEX, and higher CV in the treated eyes.