The long-term outcome of glaucoma filtration surgery

PURPOSE: To determine the long-term outcome of glaucoma filtration surgery in preserving vision. Visual loss from progressive glaucomatous damage and from complications of surgery, both short and long term, were included. METHODS: A retrospective, community-based, longitudinal study of residents of Olmsted County, Minnesota, who were newly diagnosed with open-angle glau coma between 1965 and 1980 and underwent filtration surgery in these or sub sequent years through 1998. Intraocular pressure (IOP), visual acuity, visu al fields, and progression to legal blindness were monitored. Kaplan-Meier analysis was used to determine the cumulative probabilities of changes in t hese parameters. RESULTS: 73 eyes of 49 patients underwent conventional filtration surgery, Analysis of the first eye having surgery revealed a mean preoperative IOP o f 27.6 +/- 8.5 mm dropping to 16.7 +/- 5.6 mm at year one, and remaining in this range throughout follow-up (14.7 +/- 3.0 mm at 10 years; with or with out use of medications). The probability of progression to blindness was 46 % at 10 years after surgery, as calculated by Kaplan-Meier analysis, Eyes g oing blind had a postoperative IOP equal to or lower than those not becomin g blind (14.6% +/- 4.4 vs, 15.4 +/- 3.0 at postoperative year 10), Eyes goi ng blind had more advanced field loss at the time of surgery, with scotomas above and below the horizontal axis, than eyes not going blind, which had scotomas in only one hemifield. Three patients developed late bleb leaks; t wo patients developed endophthalmitis. The probability of undergoing catara ct surgery was 37% by 10 years postoperatively, which did not differ signif icantly from the cohort of patients not undergoing surgery at a comparable time point. CONCLUSIONS: Filtration surgery was associated with a 54% probability of pr eservation of vision from progression to legal blindness at 10 years after surgery. Patients becoming blind had more advanced field loss at the time o f surgery; IOP was similar between those going blind and those retaining vi sion. (Am J Ophthalmol 2001; 132:27-35. (C) 2001 by Elsevier Science Inc. A ll rights reserved).