Epidemic optic neuropathy in primary school children in Dar es Salaam, Tanzania

Abstract

Background-An epidemic of bilateral optic neuropathy is aVecting large numbers of people aged between 10 and 40 in Dar es Salaam, the capital city of Tanzania. The disease is characterised by acute onset of bilateral visual impairment, bilateral impairment of colour vision, and a characteristic temporal pallor of the optic discs. The disease often occurs in association with peripheral neuropathy and sensorineural hearing loss. This report presents the first data on disease prevalence in adolescents, based on a rapid assessment of schoolchildren. Methods-Three schools in Dar es Salaam were visited and all children aged between 10 and 16 were screened for the disease. Results-The prevalence of bilateral optic neuropathy among the schoolchildren is estimated to be 1.0% (95% CI 0.5-1.4%). This suggests that 5000 children (95% CI 2600-7300) aged 10-16 in Dar es Salaam may have the disease. Conclusion-The results of this rapid assessment indicate this epidemic is a major public health problem. The prevalence of the disease in the community is likely to be far higher than found in this survey because children with the disease may have withdrawn from school. As the disease predominantly aVects young adults, resulting in impaired vision and hearing, the economic and social consequences are enormous. (Br J Ophthalmol 1998;82:232-234)

Optic neuropathy endemic in secondary school children in Dar es Salaam, Tanzania

“…The prevalence estimate in our study (0.3 (95% CI 0.25 to 0.35)%) was lower than that from a 1997 study in Dar es Salaam secondary schools (1 (95% CI 0.5 to 1.4)%),2 possibly suggesting a drop in prevalence. Although the sample size was smaller in the 1997 study and only involved three schools, our data did not reveal any clustering by school to suggest that the 1997 sample may have been unrepresentative.…”

“…A survey of school children (aged 10 to 16 years) performed in 1997 identified optic neuropathy to be an important cause of visual impairment, with a prevalence of 1 (95% CI 0.5–1.4)% 2. The disease usually presents in older children and young adults, who complain of sub-acute visual loss that is usually bilateral.…”

Low Prevalence of Bilateral (Presumed Nutritional) Optic Neuropathy as a Cause of Blindness in The Gambia

“…Data on B-vitamin status indicate rare deficiencies in vitamin B 12 and folate in the rural Gambian population at the time of the survey (17), which may, at least in part, explain the low prevalence of bilateral optic neuropathy, in The Gambia compared with Tanzania. (10,12,18,19).…”

Low folate status and indoor pollution are risk factors for endemic optic neuropathy in Tanzania

“…Cases were defined as 12–25-year olds presenting within 12 months of symptom onset with bilateral, simultaneous visual loss and reduced acuity in both eyes of 6/9 or worse, plus either one of: typical fundal appearance (disc pallor and nerve fibre layer abnormalities) or reported deafness/neurological symptoms such as burning of the hands and feet 2 9…”