A prospective longterm study of primary chronic angle closure glaucoma

PURPOSE: To prospectively evaluate the longterm outcome of therapy for chronic primary angle closure glaucoma (PACG) and to assess the efficacy of medical and surgical treatment in terms of intraocular pressure (IOP) and visual field stabilization. METHODS: Seventy consecutive patients with chronic PACG, whose IOP remained > 21 mmHg despite a patent iridotomy, had their IOP controlled by medications or trabeculectomy performed without antimetabolites. They were followed over a 6-year period. Best corrected visual acuity, IOP (mean of annual diurnal variation readings), cup : disc ratio and visual fields were recorded. A trabeculectomy was performed if the IOP was not adequately controlled on maximal tolerable medical therapy or if there was a progression of the glaucomatous defect. Data from one eye of each patient were analysed; if both eyes met the inclusion criteria, one was randomly selected for the analysis. The baseline parameters were compared with those at the end of 6 years. RESULTS: A total of 46 eyes (65%) were controlled medically throughout the 6-year follow-up period, while 24 eyes (35%) required surgery. The mean IOP was 25.4 +/- 4.9 mmHg at baseline and 15.6 +/- 4.6 mmHg at 6 years follow-up (p < 0.001). Stereoscopic evaluation of the cup : disc ratio did not show a significant change from a mean of 0.6 +/- 0.18 at baseline to a mean of 0.64 +/- 0.2 at 6 years (p = 0.12). Progression of visual field defects was seen in seven eyes (10%), which had statistically larger cup : disc ratios (p = 0.04) and more extensive visual field deficits at the initial assessment (p = 0.04), and which also maintained higher levels of IOP (p = 0.03) over the 6 years of follow-up. CONCLUSIONS: Stable visual fields and good longterm IOP control were seen in 90% of chronic primary angle closure glaucoma eyes on medical/surgical therapy over 6 years.