Abstract
Purpose:
Ocular hypotony is a common complication that arises from the use of antifibrotic agents during trabeculectomy. The aim of this retrospective cohort study was to identify preoperative and intraoperative factors associated with hypotony after trabeculectomy in glaucoma patients.
Methods:
We examined the medical records of adult patients who underwent primary trabeculectomy by one surgeon between 1990 and 2013 at the Stein Eye Institute. Patients were considered to have postoperative hypotony if they had one or more intraocular pressure (IOP) readings ≤ 5 mmHg after surgery. Additional outcomes examined included short-term hypotony (<3 months from surgery), long-term hypotony (≥3 months after surgery), complicated hypotony (presence of maculopathy, choroidal detachment, suprachoroidal hemorrhage, anterior chamber reformation, endophthalmitis, and/or blebitis), and uncomplicated hypotony. Odds ratios (ORs) and 95% confidence intervals (CI) were calculated to examine associations between preoperative/intraoperative factors and each type of hypotony.
Results:
Of 135 eyes of 96 patients, 107 eyes (79.3%) experienced postoperative hypotony. Sixty-three eyes (46.7%) had short-term hypotony, 44 (32.6%) had long-term hypotony, 23 (17.0%) had complicated hypotony, and 54 (40.0%) had uncomplicated hypotony. For every 1 mmHg increase in mean preoperative IOP, the odds of any hypotony decreased by 5% (OR=0.95, 95% CI=0.91-0.99). History of ocular surgery other than cataract surgery decreased the odds of short-term hypotony (OR=0.33; 95% CI=0.11-0.96), but increased the odds of long-term hypotony (OR=3.04; 95% CI=1.15-8.01). Compared to hyperopic eyes, eyes with no refractive error had increased odds of short-term hypotony (OR=6.00, 95% CI=1.30-27.77) and decreased odds of long-term hypotony (OR=0.10, 95% CI=0.01-0.87) while myopic eyes had decreased odds of uncomplicated hypotony (OR=0.33, 95% CI=0.14-0.81). The odds of complicated hypotony decreased with a family history of glaucoma (OR=0.20, CI=0.06-0.70) and increased with more sutures used during surgery (3 vs. 2, OR=5.40, CI=1.34-21.79; 4 vs. 2, OR=4.05, CI=1.04-15.82).
Conclusions:
Several preoperative and intraoperative factors are associated with hypotony after trabeculectomy. Factors associated with multiple types of hypotony included refractive error and history of prior ocular surgery. Additional studies are needed to examine risk factors and visual outcomes for hypotony following trabeculectomy.