Glaucoma in large-scale population-based epidemiology: a questionnaire-based proxy

Purpose To improve upon self-reported glaucoma status in population-based cohorts by developing a questionnaire-based proxy incorporating self-reported status in conjunction with glaucoma-specific visual complaints. Methods A vision specific questionnaire, including questions from the National Eye Institute Visual Functioning Questionnaire-25 (NEI-VFQ-25) was administered to 79,866 Lifelines participants, a population-based cohort study in the Northern Netherlands. We compared NEI-VFQ-25 responses between 'definite' glaucoma cases (n = 90; self-reported surgical cases) and an age- and gender-matched subset of controls (n = 1,800) to uncover glaucoma-specific visual complaints, using a case-control logistic regression. We defined 'probable glaucoma' as both self-reported disease status and visual complaints, and 'possible glaucoma' as either. To evaluate the resulting proxy, we determined age-stratified glaucoma prevalences in the remaining cohort and compared the result to the literature. Results Per unit increase in the vision subscales (range 0-100) distance, peripheral and low luminance, we observed significantly increased odds of definite glaucoma (2% [P = 0.03], 4% [P = 1.2 x 10(-8)] and 2% [P = 0.02], respectively); the associated area under the curve was 0.73. We identified 300 probable and 3,015 (1,434 by self-report) possible glaucoma cases. Standardised prevalences of definite, probable and possible glaucoma for 55+ were 0.4%, 1.1% and 7.3%, respectively. For self-reported glaucoma (combining definite, probable and possible by self-report), this was 5.2%. Conclusions The combination of self-reported glaucoma status and visual complaints can be used to capture glaucoma cases in population-based settings. The resulting prevalence of combined definite and probable glaucoma (1.5%) appears to be more consistent with previous reports than the prevalence estimate of 5.2% based only on self-report.

Automated summary

Combining self-reported glaucoma status with glaucoma-specific visual complaints can improve the accuracy in identifying glaucoma cases in population-based studies. The prevalence of combined definite and probable glaucoma is found to be 1.5%, which is more consistent with previous reports compared to the prevalence estimate of 5.2% based only on self-report.