Somerset and Avon Eye Studies: Chronic Open Angle Glaucoma Prevalence

Abstract

Abstract: : Purpose: To estimate the prevalence of chronic open angle glaucoma in South-West England Methods: The Somerset and Avon Eye Studies were a pair of population based cross sectional eye studies conducted amongst people aged 40 years and over living in and around Bristol in SW England. A population based sampling frame was generated from 23 general medical practices. Potential participants were invited to attend a research clinic to undergo functional, ophthalmologic and other assessments, including visual acuity, supra-threshold visual field, slit-lamp biomicroscopy, tonometry, and fundus examination. Individuals were categorised into five pragmatically defined groups according to COAG likelihood. Categorisation was based on clinical judgment of repeatable visual field loss, characteristic optic disc excavation and raised intra-ocular pressure. Results: From a selected sample of 3772, 2422 (64.21%) individuals underwent full assessments. Of those eyes examined 4040 (83.5%) were defined as definitely not COAG, 471 (9.7%) as probably not COAG; 246 (5.1%) as possible COAG; 41(0.9%) as probable COAG and 41 (0.9%) as definite COAG. Collapsing this 5 step grading scale to a dichotomous glaucoma present / absent decision revealed that 47/2422 individuals had COAG (1.95%, 95%CI 1.46-2.57). Crude COAG prevalence increased with age by decade (p<0.001). By logistic regression (adjusted for clustering between eyes within subjects) family history of glaucoma was associated with presence of glaucoma (OR=3.8, 95% CI 2.0-7.5, p<0.001), while gender, systolic and diastolic blood pressure, and frequency of attendance for sight tests were not associated. Conclusions: The prevalence of COAG and relationship with age observed in this region, based upon pragmatic and conservative clinical judgement, was broadly in agreement with the findings of other population based studies in predominantly white populations. Acknowledgement: Somerset and Avon Eye Study Groups

Keywords: clinical (human) or epidemiologic studies: pre