Glaucoma severity at first presentation to an ophthalmologist and risk factors for late presentation in rural Australia: the S1P study.

ABSTRACT

CLINICAL RELEVANCE Well-targeted referrals and timely commencement of treatment are essential to limiting vision loss in glaucoma. Optometrists, primary care providers, and public health policymakers can utilise predictors of late to identify and target at-risk populations. BACKGROUND: This study, which aimed to evaluate glaucoma severity at first presentation to an ophthalmologist in a rural Australian population, is the first of its kind in an Australian population. METHODS: Patient records from a large ophthalmology clinic in Port Macquarie, NSW were retrospectively reviewed using the Fight Glaucoma Blindness registry to identify patients who were first diagnosed with glaucoma at an ophthalmology practice in 2020 or 2021. Associations with glaucoma severity at presentation, measured with visual field index (VFI), were analysed using a beta-regression model. Retinal nerve fibre layer measurements were evaluated as a secondary outcome measure using linear regression. RESULTS: From 3548 new patients seen, 110 cases of glaucoma were diagnosed, 95 of whom met inclusion criteria. These comprised 41.8% primary open-angle glaucoma, 32.7% normal-tension glaucoma, 11.8% secondary open-angle glaucoma, 12.7% primary angle closure glaucoma, and 0.9% secondary angle closure glaucoma. The median VFI at presentation was 94.5%, and 71.9% of patients had a VFI ≥ 90%. However, 6.3% of patients presented with a VFI below 50%. Older age, higher intraocular pressure, and worse visual acuity were significantly associated with severity at presentation. No associations were found for remoteness, sex, family history, or glaucoma type. CONCLUSIONS: Glaucoma appears to be diagnosed relatively early in this population. Severity at presentation was associated with age, intraocular pressure, and visual acuity, but not influenced by the social determinants assessed. These findings underscore the importance of frequent comprehensive eye examinations in older patients. Replication in other Australian populations is recommended as the generalisability of these findings is limited.