The long-term outcome of glaucoma filtration surgery

https://doi.org/10.1016/S0002-9394(01)00923-0Get rights and content

Abstract

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 glaucoma between 1965 and 1980 and underwent filtration surgery in these or subsequent years through 1998. Intraocular pressure (IOP), visual acuity, visual fields, and progression to legal blindness were monitored. Kaplan-Meier analysis was used to determine the cumulative probabilities of changes in these parameters.

RESULTS: 73 eyes of 49 patients underwent conventional filtration surgery. Analysis of the first eye having surgery revealed a mean preoperative IOP of 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 without use of medications). The probability of progression to blindness was 46% at 10 years after surgery, as calculated by Kaplan-Meier analysis. Eyes going blind had a postoperative IOP equal to or lower than those not becoming blind (14.0 ± 4.4 vs. 15.4 ± 3.0 at postoperative year 10). Eyes going 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; two patients developed endophthalmitis. The probability of undergoing cataract surgery was 37% by 10 years postoperatively, which did not differ significantly from the cohort of patients not undergoing surgery at a comparable time point.

CONCLUSIONS: Filtration surgery was associated with a 54% probability of preservation of vision from progression to legal blindness at 10 years after surgery. Patients becoming blind had more advanced field loss at the time of surgery; IOP was similar between those going blind and those retaining vision.

Section snippets

Methods

This study is a retrospective, community-based, longitudinal study of residents of Olmsted County, Minnesota, who were newly diagnosed with open-angle glaucoma between 1965 and 1980, and underwent filtration surgery in these or subsequent years through July 1999. The time period for inclusion of patients in this cohort was chosen to allow for adequate long-term follow-up after diagnosis and surgery. Note that treatment and follow-up continued throughout the period from 1965 to 1999.

Study

Results

A total of 84 eyes from 58 patients underwent filtration surgery. The majority had primary open angle glaucoma (POAG) (67%: 39/58 patients), followed by pseudoexfoliative glaucoma (21%: 12/58 patients), low tension glaucoma (3 patients), pigmentary glaucoma (2 patients), juvenile, and neovascular glaucoma (1 patient each). Over half were female (64%: 37/58). The mean age at first filtrating surgery was 71 ± 14 years (median: 76 years). The median follow-up time postoperatively was 8 years with

Discussion

A slow progression to legal blindness occurred in some patients despite filtration surgery. Kaplan-Meier survival analysis, which accounts for variable follow-up periods, calculates a 22% probability of blindness at 5 years and a 46% probability at 10 years. The IOP in patients going blind was usually equal to or lower than in patients not becoming blind at each time point. Preoperative field loss was more extensive in patients becoming blind, however, with scotomas both above and below the

Cited by (0)

Supported in part by National Institutes of Health research grant EY 07065, an unrestricted grant from Research to Prevent Blindness, Inc., New York, NY, The Bonner Foundation, Princeton, NJ, and Mayo Foundation, Rochester, MN.

View full text