Long-term Impact of Intravitreal Injections on the ocular surface; a 2-year follow-up study

Intravitreal injection (IVI) therapy is the most frequently performed intraocular procedure worldwide, with topical povidone-iodine (PVP-I) as the standard pre-injection antiseptic. However, PVP-I has been shown to exert cytotoxic effects on the ocular surface. The purpose of this study was to evaluate the impact of two years of serial anti-vascular endothelial growth factor (VEGF) IVI on ocular surface parameters.

Patients with neovascular age-related macular degeneration (nAMD) receiving unilateral intravitreal anti-VEGF injections were examined at two time points, separated by a two-year interval. An aseptic protocol with PVP-I was applied prior to each injection. Tear meniscus height (TMH), bulbar redness (BR), and meibomian gland (MG) loss were assessed using the Oculus Keratograph 5M, with the fellow eye serving as control. For statistical analysis, the related-samples Wilcoxon signed-rank test was applied to non-normally distributed data, and the paired-sample Student's t-test to normally distributed data.

Sixty patients (mean age, 78.6 ± 8.5 years; range, 55-96) were included. Between examinations, patients received a mean of 15.5 ± 6.5 IVI (range, 5-30). A significant increase in mean BR was observed in untreated fellow eyes compared with baseline measurements (1.68 ± 0.47 vs. 1.41 ± 0.46; p < 0.001). At follow-up, BR was significantly higher in fellow eyes than in treated eyes (p < 0.001), and this difference had increased over the study period. Median TMH increased significantly in untreated eyes (0.42 mm [IQR, 0.28-0.57] vs. 0.31 mm [IQR, 0.23-0.47]; p = 0.003), whereas the increase in treated eyes was not significant (p = 0.74). At follow-up, mean TMH did not differ significantly between treated and fellow eyes (p = 0.15). Both treated and untreated eyes showed significant MG loss after two years of serial IVI; however, no significant differences in mean MG loss were detected between eyes in either the upper or lower eyelid at follow-up.

Eyes receiving repeated intravitreal anti-VEGF injections with preoperative PVP-I antisepsis were significantly less hyperemic than fellow untreated eyes, and this difference increased over two years of continued treatment. Potential mechanisms include a beneficial alteration of the ocular surface microbiome by PVP-I or an antiangiogenic effect of anti-VEGF therapy.

https://clinicaltrials.gov/study/NCT04458012, identifier NCT04458012.