Causes of severe visual impairement and blindness among children: A Case of Mbarali District in Southern Tanzania

Abstract

Objective: To determine the anatomical causes and diagnosis leading to severe visual impairment and blindness and explore their relationship to demographic characteristics among children in Mbarali district, Southern Tanzania.
Materials and methods: Key informants were trained on how to identify children with poor vision and other ocular abnormalities. Key informants identified, listed and referred for examination children with poor vision, white pupillary reflex, squint, and smaller and bigger than normal eyes. Children with a visual acuity of <6/60 in the better eye were recruited for the study. Cycloplegic refraction, anterior and posterior segment and ocular alignment examination were performed to ascertain the cause of Severe Visual Impairment (SVI) or Blindness (BL).

Results: Sixty six children had a visual acuity (VA) of <6/60. Seventy percent were 5 years or more. The mean age was 9.18(±4.42) (SD =4.42) years. Thirty five (53%) were females. Forty eight (72.7%) had SVI (VA<6/60) while 18 (27.3%) were BL (VA<3/60). Lens related conditions (27.3%), uncorrected refractive error (15.2%) and corneal related disorders (13.6%) were the commonest causes of SVI/BL. Majority of children with lens related conditions (72.2%), uncorrected refractive error and congenital glaucoma (75%) were females, while all 6 children with cortical blindness were males. Lens related and cortical blindness conditions were commoner among under-five than among older children (6/20, 30% vs 12/46, 26%) and (4/20,20% vs 2/46, 4%). Un-operated cataract was the leading diagnosis causing SVI/BL. Only 4 patients were operated for cataract. There was only one patient with phthisis-bulbi related to keratomalasia.
Conclusion and Recommendations: Lens related conditions, specifically cataract was the leading cause of SVI/BL. Recruitment of an eye-doctor at Mbarali District Hospital and establishment of tertiary eye services at Mbeya Zonal Referral Hospital are recommended to enable identification, referral and comprehensive tertiary management of children with eye conditions.