Magnitude and causes of visual impairment and blindness among children attending paediatric eye clinic at Muhimbili National Hospital, 2010

ABSTRACT Background: The number of blind years resulting from blindness in children is alarmingly high. Blindness in children can have a significant impact on their performance at school as well as their social interaction and future employment as visually impaired children have a long lifetime of blindness ahead of them. The consequences of visual impairment and blindness in children are an important public health issues with greater impact in developing countries, where 80% of the blindness in children occurs. The control of blindness in children is considered a high priority area within the World Health Organization’s VISION 2020 initiative. However many developing countries do not have the accurate information about the magnitude and causes of visual impairment and blindness in children, from which the scope and priorities for prevention and treatment can be identified. To date the established pediatric eye clinic which works as a tertiary eye centre does not have baseline data on the magnitude and causes of visual impairment and blindness in children. Objective: To determine the magnitude and causes of visual impairment and blindness in children attending pediatric eye clinic at Muhimbili National Hospital, Dar es salaam Tanzania 2010. Methodology: A cross-sectional study was conducted between June and December 2010. A total of 232 children aged 15 years and below attending pediatric eye clinic at the Muhimbili National Hospital were enrolled. Interview and physical examination was done. The visual acuity of 201 children was assessed by quantitative methods while that of 31 children was assessed by light fixing and following Method. Results: Among the 201 children assessed by quantitative methods 8% had visual impairment and 4.0% were blind. Of the 62 eyes evaluated by light fixating and following method, 8 (12.9%) vi eyes were not able to fixate and follow light. There were multiple causes of visual impairment and blindness among the affected children. Ocular trauma was the predominant cause of both uniocular visual impairment and blindness causing 15, 29.4% and 17, 34.7% respectively. Amblyopia due to congenital cataract was the leading cause of bilateral visual impairment accounting for 31.3% while cortical blindness was the main cause of bilateral blindness responsible for 50.0% of bilaterally blind children. Abnormalities of the optic nerve emerged as an important cause of visual impairment and blindness which affected 7(43.8%) visually impaired children and 2 (25.0%) blind children. Conclusion: Visual impairment and blindness in children is high among the children attending the pediatric eye clinic at Muhimbili National Hospital with younger children being more affected with blindness than the older ones. Corneal scaring due to measles and vitamin A deficiency were not seen as the causes of visual impairment and blindness in these children. Efforts towards prevention of ocular trauma among children and improvement of antenatal and natal care so as to reduce birth asphyxia and consequently cortical blindness should be emphasized