The distribution of cup disc ratios in a general population of Southern Togo aged 40 years and over

PURPOSE: Clinical reports and epidemiological surveys have raised the key issues of both the burden of glaucoma blindness and the high prevalence of the disease among the populations of Togo. This population survey aimed to collect data on the distribution of cup disc ratios. PATIENTS AND METHODS: The study population of 685 persons was selected in a remote rural area. All participants aged over 40 years were included. Eye assessment was conducted in the local health facilities using a visual acuity chart, an ophthalmoscope and light magnification for exploration of the anterior segment. RESULTS: The mean age of participants was 49.70 years (range, 40-99 years); men accounted for 61.8% and women 38.2%. Mean cup disc ratios were not different in both eyes, with 0.38 in the right eye and 0.37 in the left. Cup disc ratios over 0.5 represented 29.3% in the right eye and 29.8% in the left one; a cut-off point over 0.7 gave an abnormal cup ratio prevalence of 9.2% in the right eye and 9.3% in the left eye. In 92% of cases, the appearance of the cupping was round, and was elliptic in 7.6% of patients. We found that 75% of discs had a central round cupping. The temporal location was noted in 22% of cases while nasal locations were recorded in 2.4%. CONCLUSION: This survey has noted the various patterns of cup discs, with the mean cup disc ratio similar to what is usually described in similar studies. Further population-based surveys using the cut-off ratios found here are needed to determine the prevalence of glaucoma in this rural area.