Magnitude and causes of low vision in adults attending the eye clinic at Muhimbili National Hospital

Abstract

Background: Globally, in 2006, World Health Organization (WHO) estimated that there were 314million visually impaired people in the world, 153 million of them being due to uncorrected refractive error. At least 45 million working adults aged between 16-49 years were affected globally.1According to the WHO low vision is visual acuity of less than 6/18 but equal to or more than3/60 in the better eye with best possible correction or with significant visual field loss (corresponding visual field loss of less than 20 degrees)2. A person with low vision has some residual useful vision, with the potential for enhancement of functional vision if they receive appropriate low vision care services.Several studies have been done on low vision in other countries; the available literature reveal that the studies done in Tanzania were mostly among children, there is no study on low vision which has been done among adults. Objective:To determine the magnitude and causes of low vision in adults attending theeye clinic at Muhimbili National Hospital, Dar es salaam Tanzania. Methodology:A cross-sectional study was conducted between April and September, 2011. A total of 561 patients who attended the general eye clinic at Muhimbili National Hospital were thoroughly assessed and treated by ophthalmologists and refractionists. One hundred patients whose vision did not improve to 6/18 and above after surgical, medical and optical treatment were referred to the low vision clinic. These 100 patients were enrolled in the study and complete low vision assessment was done. Data were entered in computer and analyzed using SPSS version 13. Results:Among 561 patients, there were 100(17.83%) patients with low vision.group of 18-27 years age, and a gradual trend of decrease in low vision patients with increasing age (0.2% in eldest age group of 78-87 years) was observed. Optic neuropathy was the predominant cause of low vision (47%) in the study population, followed by ARMD (9%), Retinitis pigmentosa (7%), glaucoma (7%), albinism (7%), amblyopia (7%), corneal diseases (5%), refractive errors (4%), diabetic retinopathy (4%) and macular scars (3%). Conclusion:The magnitude of Low vision is high among adults attending the eye clinic at Muhimbili National Hospital, with younger patients being affected more than older ones. Most causes are either treatable or preventable.