Comparison of Surgically Induced Astigmatism Between Baerveldt Glaucoma Implant Surgery and Trabeculectomy: A Retrospective Cohort Study

TL;DR

This study compares how much corneal astigmatism is caused by two glaucoma surgeries and finds that one causes more astigmatism than the other.

Contribution

The study provides a direct comparison of surgically induced astigmatism between Baerveldt glaucoma implant surgery and trabeculectomy.

Findings

BGI surgery caused greater surgically induced astigmatism than trabeculectomy.

BGI surgery and lower preoperative astigmatism were independently linked to greater postoperative astigmatism.

Older age predicted more astigmatism after BGI surgery but not after trabeculectomy.

Abstract

Objectives: This study aimed to compare surgically induced corneal astigmatism (SIA) between Baerveldt glaucoma implant (BGI) surgery and trabeculectomy and to identify prognostic factors associated with SIA. Methods: This retrospective cohort study included 109 and 229 eyes that underwent BGI surgery and trabeculectomy, respectively, at Fukui University Hospital. Corneal astigmatism was assessed preoperatively, and at 6 months postoperatively, the mean SIA (M-SIA) and centroid SIA were calculated, and factors associated with M-SIA were determined. Results: BGI surgery was associated with greater SIA than trabeculectomy. Postoperative corneal astigmatism was −1.53 ± 1.01 D in the BGI group and −1.33 ± 0.92 D in the trabeculectomy group (p = 0.044). The M-SIA was significantly larger in the BGI group (1.41 ± 1.05 D vs. 0.94 ± 0.74 D, p < 0.01). Multivariate regression revealed that BGI surgery and lower preoperative corneal astigmatism were independently associated with greater M-SIA. Subgroup analysis revealed that older age and lower preoperative astigmatism were significant predictors of larger M-SIA in the BGI group, whereas only preoperative astigmatism was significant in the trabeculectomy group. Conclusions: BGI surgery was associated with greater and more variable SIA than trabeculectomy. Surgical type, baseline astigmatism, and age are important predictors of postoperative SIA.