Visual Acuity, Not Pressure Control, Distinguishes Phacotrabeculectomy from Trabeculectomy in Primary Open-Angle Glaucoma: A Six-Month Comparative Cohort Study

Abstract

Background: Primary open-angle glaucoma often coexists with cataract, but Indonesian evidence comparing trabeculectomy with combined phacotrabeculectomy is scarce. Objective: To compare six-month pressure, medication, surgical, and visual outcomes after trabeculectomy versus phacotrabeculectomy and quantify between-group precision. Methods: This retrospective, non-randomised comparative cohort included 74 consecutive patients with primary open-angle glaucoma (54 trabeculectomy; 20 phacotrabeculectomy) at an Indonesian university ophthalmology department. Outcomes were intraocular pressure, topical medication burden, surgical success, and visual acuity. Within-group changes used paired t tests with Holm adjustment; between-group contrasts used Welch and Fisher exact tests, Hedges g, and Newcombe intervals. Result: Pressure fell at every timepoint in both groups (all adjusted p < 0.001). Six-month reductions were 13.02 and 12.10 mmHg; the between-group difference was 0.92 mmHg (95% CI −5.27 to 3.43; p = 0.670). Complete success was 55.6% versus 75.0% (odds ratio 2.40, 95% CI 0.76–7.55; p = 0.181). Visual acuity favoured phacotrabeculectomy (0.37 versus 0.99 logMAR; Hedges g = 0.70, 95% CI 0.18–1.23; p = 0.020). The cohort could not resolve pressure differences below 5.99 mmHg. Conclusion: Both procedures achieved large, sustained reductions in pressure and medication burden; equivalence in pressure control was not established. Phacotrabeculectomy produced better visual acuity, although cataract confounded procedure selection and acuity. When cataract coexists with primary open-angle glaucoma, the combined procedure may provide comparable pressure control and better acuity in one admission.