Beyond prevalence: diagnostic heterogeneity in population-based glaucoma studies in Africa–a systematic review

Glaucoma represents a disproportionately high burden in Africa. A systematic review examined the diagnostic criteria used to define glaucoma in population-based studies across Africa. The analysis included nine studies classified according to adherence to the International Society of Geographical and Epidemiological Ophthalmology (ISGEO) criteria. The use of ISGEO definitions varied significantly among studies, with major sources of variation including intraocular pressure thresholds, optic nerve head assessment, visual field testing, and gonioscopy application. Studies using complete ISGEO definitions reported glaucoma prevalence ranging from 4.3% to 5.3%, while studies employing partial or non-ISGEO approaches reported a broader range of 2.1% to 8.4%. The proportion of previously diagnosed glaucoma cases was low, ranging from 3.3% to 14.3%. The review emphasizes the need for standardized reporting of diagnostic protocols to improve comparability of future epidemiological studies.