Eyes of Africa: The Genetics of Blindness. Baseline characteristics, ocular features, and associations with glaucoma in continental Africans.

IMPORTANCE

Glaucoma is the leading cause of irreversible blindness worldwide, with disproportionately high prevalence and severity in Africans.

OBJECTIVE

To characterise the baseline phenotypic findings and glaucoma-related ocular features of participants with primary open-angle glaucoma (POAG, cases) and non-glaucoma controls and to report sociodemographic and medical associations of POAG in the cohort.

DESIGN

Multicentre, cross-sectional study.

PARTICIPANTS

9418 adults (5189 POAG cases; 4229 controls) recruited from 16 centres in Nigeria, Ghana and Malawi.

METHODS

Standardised demographic, medical and ophthalmic data were collected, including visual acuity, intraocular pressure (IOP), optic disc evaluation, visual fields and central corneal thickness.

MAIN OUTCOME MEASURES: Glaucoma severity, visual impairment (VI) and sociodemographic/medical associations of POAG.

RESULTS

Compared to controls, cases were older (mean age 63.9 years vs 61.4 years, P < 0.001) and more likely to be male (57.4% vs 45.2%, P < 0.001). Three-quarters of cases (76.8%) were classified as having severe glaucoma in at least one eye at recruitment, with a third (34.4%) suffering severe VI or blindness. The leading causes of VI in controls were cataract (65.0%) and uncorrected refractive error (13.8%). POAG was significantly associated with older age, male sex, higher level of education, unemployment, history of alcohol consumption, African trypanosomiasis, higher maximum IOP and a positive family history of glaucoma.

CONCLUSION

There is a significant glaucoma disease burden in sub-Saharan Africa. Further analyses of the cohort will identify genetic determinants of these clinical findings and reinforce the urgent need for public health interventions in sub-Saharan Africa.