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Michael Murri, Avni Shah, Brad Jacobsen, Molly McFadden, Arwa Alsamarae, Brock Alonzo, Akbar Shakoor, Jeff H Pettey; Prevalence of Glaucoma in an East African population in Mwanza, Tanzania. Invest. Ophthalmol. Vis. Sci. 2020;61(7):70.
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© ARVO (1962-2015); The Authors (2016-present)
To determine glaucoma prevalence and associated factors in an adult African population in East Africa.
Cross-sectional, population-based study of participants aged 18 and older attending a health screening in the mixed rural/urban lake zone of Mwanza in northern Tanzania. All participants underwent an ophthalmic exam, which included LogMAR visual acuity, intraocular pressure (IOP) measurement (Tono-pen, Reichert, Buffalo, NY), and optic disc photographs (TRC NW300 or TRC NW8F, Topcon, Tokyo, Japan). Participants also filled out a demographic survey. Two independent graders then graded the photos; a third independent grader served as a tiebreaker when needed. Glaucoma was defined by optic disc criteria consistent with prior studies, namely: a cup to disc(C:D) ratio of 0.9 or higher, or a C:D ratio of 0.7 or higher with one or more of the following additional features: a definitely abnormal nerve fiber layer, at least one clock hour of complete optic disc rim loss, or C:D asymmetry between eyes of 0.3 or greater. In the case of ungradable photos, glaucoma was also defined by vision <3/60 with IOP >30.
1074 individuals were assessed for glaucoma. 31 (2.9%) had glaucoma in one or both eyes, 25 by optic disc criteria and 6 by vision/IOP criteria. The prevalence increased significantly with age: 0.9% in those under 50, 1.4% in those 50-60 and 7.5% in those over 60 (p<0.001). Average IOP was 10 mmHg higher in glaucomatous eyes (25.9 mm Hg) compared with healthy eyes (15.3 mm Hg) (p<0.001). The eyes with glaucoma had an odds ratio of 9.3 for blindness compared to those without glaucoma (95% CI: 3.8-22.4) p <0.0001), with 80.6% presenting with blindness in one eye and 41.9% presenting bilaterally blind. Glaucoma was also significantly associated with being unemployed (p<0.007). No glaucoma patients had received prior medical or surgical treatment for their disease, per their history.
Prevalence of glaucoma in the Mwanza region of northen Tanzania appears higher than in a previous study in rural Tanzania performed two decades ago, with many patients presenting already blind. Efforts to increase public awareness and train glaucoma practitioners in East Africa must be supported to begin to close this gap.
This is a 2020 ARVO Annual Meeting abstract.
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