Prevalence of eye diseases in primary school children in a rural area of Tanzania.

AIMS: The study measured the prevalence of eye diseases in primary school children between 7 and 19 years of age in a rural area of Tanzania, and investigated whether teachers could successfully provide the first component of a school eye screening service.
METHODS: Teachers from each of three primary schools in Mwanza Region tested visual acuity using a Snellen's E chart in 1438 pupils. 1386 of these pupils were then interviewed and underwent a full eye examination by an eye team.
RESULTS: 10 pupils (0.7%) had bilateral poor eyesight (visual acuity worse than 6/12), and an additional 14 pupils (1.0%) had unilateral poor eyesight. Significant refractive errors causing visual acuity less than 6/12 (1.0%), strabismus (0. 5%), and amblyopia (0.2%) were uncommon. Overall, 76 pupils (5.5%) had active trachoma, though the prevalence was 15.5% in the poorest school. 73 pupils (5.3%) reported night blindness, eight (0.6%) had Bitot's spots, and 11 (0.8%) had corneal scars. Simple screening by teachers correctly identified 80% of the pupils who were found to have bilateral poor eyesight by the eye team, with 91% specificity.
CONCLUSION: The prevalence of significant refractive errors was not high enough to justify a school eye screening programme solely for this purpose. However, a programme may be justified in areas where trachoma is common. Further research is needed to validate the frequent reports of night blindness and to establish the public health importance of vitamin A deficiency in this age group.