A twenty-year follow-up study of trabeculectomy: risk factors and outcomes

This study was undertaken to determine the performance of trabeculectomy surgery over a 20-year period and examine the associations between outcome and risk factors for trabeculectomy failure.

Retrospective cohort study.

A total of 234 patients (330 procedures) who had undergone trabeculectomy surgery at Addenbrooke's Hospital, Cambridge, United Kingdom, between January 1988 and December 1990.

Patients were identified through surgical logbooks (n = 521 procedures on 380 patients); after this, a case-note review was undertaken, which identified 234 patients (330 procedures) who had available case notes.

Surgical success was defined as "complete success" while intraocular pressure (IOP) remained <21 mm Hg with no additional medication and as "qualified success" if those requiring additional topical medication were included. Functional success was defined if patients did not progress to legal blindness (visual acuity <3/60 or visual field <10 degrees).

After 20 years, 57% were classified as complete success, 88% were classified as qualified success, and 15% had become blind. Those at risk of trabeculectomy failure were younger or had uveitic glaucoma. Those with pseudoexfoliation or aphakia were more likely to progress to blindness. Furthermore, those using 2 or more topical medications or with advanced visual field loss at the time of surgery were more at risk of both trabeculectomy failure and blindness.

This study indicates that trabeculectomy survival at 20 years may be approximately 60% with no topical medication and approximately 90% with additional topical medication. Patient age, preoperative topical medication use, glaucoma type, and glaucoma severity will independently influence this outcome. Trabeculectomy surgery is therefore a long-term solution to IOP control.