Comparison of Surgically Induced Astigmatism After Glaucoma Filtering and Implant Procedures

Purpose

To compare keratometric surgically induced astigmatism (SIA) at 3 months after trabeculectomy (LEC), EX-PRESS shunt (EXP), PRESERFLO MicroShunt (PSM), and Ahmed glaucoma valve (AGV) with ciliary-sulcus tube insertion using vector analysis, and to assess the directionality of SIA. Study Design: Single-center, nonrandomized, retrospective comparative study. Subjects and Methods: We retrospectively analyzed 100 eyes with glaucoma undergoing LEC (n = 20), EXP (n = 30), PSM (n = 30), or AGV (n = 20) at a single center. Best-corrected visual acuity (BCVA), intraocular pressure (IOP), and keratometric astigmatism were evaluated preoperatively and at 3 months postoperatively. SIA was calculated using the Jaffe vector method. Directional non-uniformity of the SIA axis was assessed using the Rayleigh test after double-angle transformation. Associations between SIA magnitude and postoperative IOP and BCVA were assessed using Spearman’s rank correlation. In the LEC group, the association between SIA magnitude and the number of residual scleral-flap sutures was also evaluated.