Dear Editor, I read with great interest the article by Mvitu and Longo-Mbenza that appeared in a recent issue of African Heath Sciences.1 In that paper, the authors were interested in determining whether diabetes is an independent and significant determinant of visual disability. I commend them for performing this study. However a closer look at Figure 1 indicates a steady increase in the rate of visual disability by more than 10% per decade. On the contrary Figure 2 shows that the rate of disability sharply decreases by more than 20% and remains unchanged over time after the disease has lasted 5 years. While Figure 1 is understandable, the message conveyed by Figure 2 is surprising and questionable. Indeed, visual impairment has repeatedly been shown to be associated with longer duration of diabetes, which together with poor diet, uncontrolled diabetes, and other factors increases the risk of diabetic retinopathy. Since this was a hospital-based study, it would have been informative to provide the readers with the number of subjects who had access to laser, subjects who were taking insulin or other drugs vs. untreated, subjects who had controlled glycemia vs. uncontrolled. Additionally, age-related macular degeneration is underreported in sub-Saharan Africa partly due to the lack of imaging modalities that may assist clinicians in the diagnosis. Assuming that long-lasting diabetes did not increase the rate of visual disability over time, once would expect Figure 2 to display a trend toward increase in the rate of disability as a result of other factors such as age-related macular degeneration, cataract, and glaucoma. Not including these age-related causes of visual loss in the multivariate analysis may have affected the outcome. I am pondering the clinical implications of this finding and seek further clarification from the authors. Sincerely, Dr. Mwanza Jean Claude