Incidence of Glaucoma Progression and Rate of Visual Field Deterioration in a Cohort of Urban Ghanaians

Precis:The annual incidence of glaucoma progression (9.7%) and rates of visual field mean deviation (MD) change in progressors (-1.02 +/- 0.06 dB/y) are high in a small cohort of urban Ghanaians. Purpose:To report the incidence of glaucoma progression and the rate of visual field deterioration in a small cohort of Ghanaians. Methods:One hundred ten subjects (204 eyes) diagnosed with glaucoma at a baseline population-based screening examination were re-examined a mean of 8.3 +/- 0.8 years later. Eyes were classified as having progressed if the optic disc alone, visual field alone or both showed significant glaucomatous changes on follow-up. Visual field MD was used to calculate the rate of visual field progression. Results:Progression was observed in 89 (80.9%, 9.7%/year) subjects (130 eyes). Progression occurred in 32 (31.7%, 3.8%/year) subjects by optic disc alone (46 eyes), 38 (44.7%, 5.4%/year) subjects by visual field alone (58 eyes), and 19 (25.0%, 3.0%/year) subjects by both modalities (26 eyes). The average rate of change in MD differed significantly between progressors (-1.02 +/- 1.06 dB/y) and nonprogressors (+0.089 +/- 0.49 dB/y), P=0.001. The rate of visual field worsening was greater among those who were classified as having progressed by both structure and function (-1.29 +/- 0.68 dB/y) and by function alone (-1.21 +/- 1.20 dB/y) than by structure alone (-0.55 +/- 0.76 dB/y). Progression was significantly associated with older age [odds ratio (OR), 1.42; P<0.001] and higher baseline intraocular pressure (OR, 1.18; P=0.002). Factors associated with rate of MD change were baseline older age (OR, 1.66; P=0.003), higher intraocular pressure (OR, 2.81; P=0.007), better visual field MD (OR, 1.41; P=0.004), and systemic hypertension (OR, 1.15; P=0.029). Conclusion:The incidence and rate of visual field progression are high in this longitudinal study of Ghanaian subjects with glaucoma. The findings may have important clinical and public health policy ramifications.