Elevated intraocular pressure and pseudoexfoliation of the lens capsule as risk factors for chronic open-angle glaucoma. A population-based five-year follow-up study.

In 1984-86, a glaucoma survey was carried out in a municipality in central Sweden, comprising 760 subjects 65-74 years of age. Since 1988, a follow-up study of those 527 subjects who had normal and reliable visual fields has been in progress. A visual field defect was required for a diagnosis of chronic open-angle glaucoma. By December 1991, 10 cases of capsular glaucoma and 3 cases of chronic simple glaucoma had been found. The standardized relative risk for chronic open-angle glaucoma was 3.4 times (95% confidence interval: 1.1-11) greater in subjects with a baseline intraocular pressure > or = 21 mmHg, using the highest pressure in either eye, than in those with an intraocular pressure < 21 mmHg. Pseudoexfoliation increased the standardized relative risk 9.8-fold (95% confidence interval: 2.5-38). There was indication of effect modification between intraocular pressure and pseudoexfoliation. Optic disc haemorrhages were associated with a 4.8-fold (95% confidence interval: 0.63-37) increased unadjusted risk. The study supports the pressure theory of optic nerve damage in glaucoma. Pseudoexfoliation was recognized as an independent risk factor for the development of chronic open-angle glaucoma.