Glaucoma Features in an East African Population: A Six-year Cohort Study of Older Adults in Nakuru, Kenya

PURPOSE: Glaucoma is a leading cause of blindness in people of African descent. Minimal data is available from African population-based cohort studies. The primary aims of this study were to describe the normative distribution of glaucoma features to enable glaucoma classification and to assess risk factors for those with glaucoma at follow-up among people aged ≥50 years in Kenya.

MATERIALS AND METHODS: Random cluster sampling with probability proportionate to size was used to select a representative cross-sectional sample of adults aged ≥50 years in 2007-8 in Nakuru District, Kenya. A six-year follow-up was undertaken in 2013-14. Comprehensive ophthalmic examination included visual acuity, digital retinal photography, visual fields, intra-ocular pressure, OCT and independent grading of optic nerve images. We report glaucoma features, prevalence and predictors for glaucoma based on the ISGEO criteria. Measures were estimated using a Poisson regression model and including inverse-probability weighting for loss to follow up.

RESULTS: At baseline, 4414 participants aged ≥50 years underwent examination. Anterior chamber OCT findings: mean anterior chamber angle of 36.6°, mean central corneal thickness of 508.1▒μm and a mean anterior chamber depth of 2.67▒mm. 2171 participants were examined at follow-up. The VCDR distribution was 0.7 and 0.8 at the 97.5 and 99.5 percentiles, respectively. A total of 88 (4.3%, 95% CI, 3.5-5.9%) of participants at follow-up had glaucoma consistent with ISGEO criteria. A RAPD and raised IOP were associated with the diagnosis.

CONCLUSIONS: Glaucoma is a public health challenge in low-resource settings. Research into testing and treatment modalities in Africa is needed.