Onchocerciasis and other eye problems in developing countries: a challenge for optometrists

J Am Optom Assoc. 1993 Oct;64(10):699-702.


Background: Onchocerciasis, also known as River Blindness, affects about 18 million people around the world, resulting in severe visual impairment or blindness for approximately 2 million.

Methods: The disease is transmitted through the bite of a tiny black fly, which breeds in fast moving rivers and streams. The fly injects immature forms of the parasite worm, Onchocerca volvulus, whose microfilariae migrate to superficial tissues, and may invade any part of the eye. In the eye, living microfilariae may be found in any ocular structure, however, sclerosing keratitis, a severe corneal involvement is the major cause of blindness from the disease.

Results: Substantial efforts are currently underway to control the disease in Latin America and equatorial Africa, now that an effective, nontoxic medication, ivermectin, is available.

Conclusions: Optometrists are helping to solve the logistic challenges for treatment of this disease, as most onchocerciasis endemic areas are remote with difficult access.

PIP: Onchocerciasis is commonly known as River Blindness and affects about 18 million people around the world. It is transmitted by black flies that breed in river and stream rapids and transmit the parasitic microfilariae, Onchocerca volvulus, to people who live and work near such rivers. Infection with the microfilariae results in blindness or visual impairment for 1 or 2 million people. The microfilariae migrate to superficial tissues and may invade any part of the eye and ocular structure. Living worms cause little damage, however, their death triggers a localized inflammation which can lead to blindness. Sclerosing keratitis, a severe corneal involvement, is the major cause of blindness from the disease. The World Health Organization (WHO) Expert Committee on Onchocerciasis has estimated that 9% of the disease is found in Africa, the rest occur in Yemen and Latin America. Treatment with ivermectin is contraindicated for pregnant and lactating women, children under 5 years of age, asthmatics, and people with other diseases. The WHO Onchocerciasis Control Program in 11 countries of West Africa has eliminated the risk of onchocerciasis by aerial spraying of black fly breeding sites only from 1 country. A single annual oral dose (150 mg/kg) of ivermectin can reverse early lesions in the cornea. Ivermectin must be taken annually to sustain protection against blindness, thus its incorporation into primary health care along with malaria, AIDS, trachoma, xerophthalmia, and cataract is most cost effective. Nigeria and Tanzania have optometry schools, and optometrists can play a significant role in onchocerciasis control and blindness prevention programs by training local health care workers to distribute invermectin in vision screening programs.

Publication types

  • Review

MeSH terms

  • Africa
  • Developing Countries*
  • Humans
  • Latin America
  • Onchocerciasis, Ocular / prevention & control*
  • Optometry*
  • Vision Disorders / prevention & control*