Abstract
Purpose :
To determine intraocular pressure (IOP) changes in the fellow eye during the early postoperative period after Ahmed glaucoma valve surgery in a prospective cohort study.
Methods :
This study followed patients undergoing Ahmed glaucoma valve surgery by a single surgeon at University of California, San Francisco between May 2013 and August 2014. IOP, visual acuity and medications were collected at the preoperative visit (baseline) and at postoperative weeks 1-2, 4, 6, 8 and 12. Patients were continued on their scheduled medications for the fellow eye postoperatively. The primary outcome was longitudinal difference in IOP of the fellow eye compared to baseline over the postoperative 12 weeks. Data was analyzed using a longitudinal, linear mixed effects regression adjusting for use of glaucoma medications.
Results :
Of the 65 patients enrolled, the majority had primary open-angle glaucoma (POAG; 51%), followed by uveitic glaucoma (29%). Fellow eyes had a significant mean increase in IOP at weeks 1-2 (2.1mmHg, SD 4.9, P=0.003), 4 (1.9mmHg, SD 4.0, P<0.001), 6 (1.5mmHg, SD 5.0, P=0.006) and 8 (0.93mmHg, SD 4.3, P=0.02) compared to baseline. There was no significant IOP elevation at week 12. Longitudinal analysis showed that fellow eyes had a significant increase in IOP from baseline (P = 0.001). Subgroup analysis demonstrated that patients with steroid-sensitive glaucoma (uveitic, post-corneal transplant, post-steroid injection) had a significant increase in IOP of the fellow eye from baseline compared to POAG or primary angle closure glaucoma (PACG; P=0.008). The most significant difference in mean change in IOP was observed at week 2 in patients with steroid-sensitive glaucoma (4.5mmHg, SD 5.8) compared to POAG or PACG (0.2mmHg, SD 3.2, P<0.001).
Conclusions :
In our analysis, patients undergoing Ahmed valve surgery had a transient but significant elevation in IOP of the fellow eye during the immediate postoperative period. This effect was mainly observed in patients with steroid-sensitive glaucoma as they may have an exaggerated response to steroids. This study highlights the importance of IOP monitoring in both eyes following Ahmed valve surgery. In steroid-sensitive patients, the potential risk of postoperative IOP elevation in the fellow eye should be discussed when considering Ahmed valve surgery.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.