Long-term follow-up of pseudoexfoliation, intraocular pressure and glaucoma : epidemiological studies in northern Sweden

Sammanfattning: Purpose An age-cohort was studied with long-term follow-up. The population was born in 1915, living in the municipality of Skellefteå in 1981. The purpose was to investigate the prevalence and incidence of pseudoexfoliation (PEX), its influence on intraocular pressure (IOP) and development of open-angle glaucoma (OAG). Another purpose was to estimate the value of screening for glaucoma by comparing the screened group within the cohort with the remaining unscreened group.Methods In 1981, 339 (40%) of the 856 individuals in the cohort underwent an eye examination. This screened group was re-examined at seven-year intervals until 2002. At each visit the presence of PEX was registered, IOP was measured and the presence of glaucoma was assessed. After the 21-year follow-up period, glaucoma cases were also searched for in the medical records of the remaining unscreened individuals in the cohort. Proportions of glaucoma were compared between the two groups.Results The prevalence of PEX was 23% (95% confidence interval (CI): 20-26%) at the age of 66 and increased to 61% (CI: 50-71%) at the age of 87. The annual incidence of PEX was 1.8% (CI: 1.3-2.4%). The prevalence of OAG increased from 2.1% (CI: 0.8-4.3%) at the age of 66 years to 25 % (CI: 16-35%) at 87 years. The overall annual incidence of OAG was 0.9% (CI: 0.6-1.3%) and for OAG with PEX 2.1% (CI: 1.2-3.3%). PEX increased the risk of developing glaucoma at least four-fold. The incidence of diagnosed OAG in women was higher in the screened group than in the unscreened group (incidence rate ratio (IRR)=1.94, p=0.035). A corresponding difference could not be verified for men (p=0.58). The mean, agedependent, increase in IOP during the 21-year observation period was 0.05 mmHg/year.Conclusion The prevalence of PEX in this study population was the highest reported, and it increased with age. The presence of PEX increased the risk of developing OAG four times. In this study a higher proportion of OAG was revealed by screening among women but not among men. The age-related IOP increase was clinically insignificant.