Optical coherence tomography and Scheimpflug imaging of the iridocorneal angle following intravitreal injection of different medications: A longitudinal analysis

Abstract

Purpose: Intravitreal injection of medications induces a sudden increase in posterior segment volume and pushes iris plane anteriorly to narrow iridocorneal angle. The aim of this study to follow and define longitudinal course of these changes following intravitreal injection of 3 different anti-vascular endothelial growth factor (VEGF) medications or dexamethasone implant.Materials and Methods: This prospective, longitudinal study included 89 eyes of 89 patients that had an intra-vitreal injection of bevacizumab (n = 20) or ranibizumab (n = 26) or aflibercept (n = 22) or dexamethasone implant (n = 21). All the participants had a detailed ophthalmological examination including anterior segment optical coherence tomography (AS-OCT) and Scheimpflug imaging of the iridocorneal angle, evaluation of anterior chamber depth (ACD), axial length with optical biometry and endothelial cell counts with specular microscopy just before the injection, at post-injection day 1, and post-injection 1st month.Results: Iridocorneal angle became significantly wider following intravitreal injection of dexamethasone implant at nasal and temporal quadrants at the post-injection 1st month both in AS-OCT (p = 0.006, p = 0.002, respectively) and Scheimpflug imaging (p = 0.003, p = 0.004, respectively). Small changes were observed in iridocorneal angle following anti-VEGF injections but these small could not be confirmed in both imaging techniques. There were also no changes in ACD, axial length and endothelial counts in all groups. Conclusion: Dexamethasone implants induced widening of iridocorneal angle that persisted at the post-injection 1st month both at nasal and temporal quadrants. However, intravitreal injection of anti-VEGF agents did not have a comparable effect on iridocorneal angle.