Long-term evaluation of trabeculectomy in primary open angle glaucoma and chronic primary angle closure glaucoma in an Asian population

Purpose: A retrospective cohort study was undertaken to evaluate and compare the long-term results of trabeculectomy in primary open angle glaucoma (POAG) and chronic primary angle closure glaucoma (CPACG) in an Asian population. Methods: Yearly diurnal measurements of intraocular pressure (IOP), best-corrected visual acuity, optic disc and visual field records of patients having primary adult glaucomas who had undergone trabeculectomy, without anti-mitotic agents, with a minimum of 5 years follow up were evaluated. Only one eye of each patient was studied. The success rates for IOP control in POAG and CPACG were statistically analysed. Results: Sixty-four eyes of 64 patients were studied. The overall probability of success of trabeculectomy in controlling IOP to less than or equal to21 mmHg with or without additional topical antiglaucoma medication was 0.94 and 0.88 at 5 and 10 years, respectively. There was no statistically significant difference in the qualified and absolute success rates for IOP control between POAG and CPACG eyes (log rank test P= 0.6, 0.88, respectively). Twelve of 38 CPACG eyes had a two-line decrease in visual acuity as compared to four of 26 POAG eyes (P = 0.17). Progression or development of a cataract was the most common cause of visual decline. Conclusions: Trabeculectomy without antimetabolite use appears to be efficacious in lowering IOP and in visual field preservation over a period of 10 years in both POAG and CPACG. Development/progression of cataract especially in eyes with chronic angle closure glaucoma after trabeculectomy must be considered an important issue.