Magnitude and causes of blindness and low vision in Anambra State of Nigeria (results of 1992 point prevalence survey)

Public Health. 1997 Sep;111(5):305-9.


A survey to determine the prevalence and causes of blindness in Anambra State of Nigeria was conducted. The aim was to provide baseline data for the planning, implementation and evaluation of both the state's and the National Programme for Prevention of Blindness. A multistage cluster random sampling technique was used. The World Health Organization/Prevention of Blindness (WHO/PBL) Eye Examination Record Form was used. The WHOs definitions of blindness and low vision were adopted for the analysis. The prevalence of blindness in the state is estimated to be 0.33% +/- 0.27%. Visual acuity of from 3/60 to less than 6/60 has a prevalence of 0.41% +/- 0.30% while visual acuity of from 6/60 to less than 6/18 has a prevalence of 0.67% +/- 0.39. There are equal numbers of blind males as females, although the prevalence among males is 0.44% +/- 0.26% while among females it is 0.24% +/- 0.15%. Most of the blind are above 50 y of age with prevalence of blindness in this age group being 2.62% +/- 1.31% (3.27% +/- 2.1% for males and 2.02% +/- 1.58% for females). Cataract caused most of the blindness (70.59%), followed by glaucoma (17.65%). Macular degeneration is becoming important (5.88%) while obvious infective causes are rare. Errors of refraction are important public eye health care problems. Methods of tackling the cataract problem (both backlog and incident), and other eye health needs within the primary eye/health care are recommended. The need to extend refraction services to the rural areas is emphasized.

PIP: To provide baseline data for the planning, implementation, and evaluation of the National Program for Prevention of Blindness, a survey was conducted in Nigeria's Anambra State. A multistage cluster random sampling technique was used to enroll 1752 adults. Blindness was defined, according to World Health Organization criteria, as visual acuity in the better eye of less than 3/60 with spectacle correction or pinhole. Low vision was defined as visual acuity less than 6/18 to not better than 6/60 (category 1) or less than 6/60 to not better than 3/60 (category 2) in the better eye with best correction or pinhole. The estimated prevalence of blindness in the sample was 0.97% (1.54% among men and 0.64% among women). When adjusted to the age and sex structure of the Nnewi North Local Government Area, this prevalence became 0.33% (0.44% for men and 0.24% for women). For those above 50 years of age, the prevalence of blindness was 2.62% (3.27% for men and 2.02% for women). Cataract was the primary cause of blindness (70.57%), followed by glaucoma (17.65%). The prevalence of category 1 low vision was 0.67%, while that of category 2 low vision was 0.41%. Finally, the prevalence of monocular visual impairment was 1.20%. In this area, blindness associated with measles and other infectious causes has decreased substantially. At present, most visual impairment is due to progressive lesions associated with aging. These findings suggest that the priority needs in Anambra State are sight restorative surgery for the cataract blind, early diagnosis and treatment of glaucoma, and provision of low-cost spectacles for the correction of ametropia. A community outreach eye care service, integrated into primary health care, is recommended.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Age Distribution
  • Aged
  • Aged, 80 and over
  • Blindness / epidemiology*
  • Blindness / etiology
  • Blindness / prevention & control
  • Child
  • Child, Preschool
  • Female
  • Humans
  • Infant
  • Infant, Newborn
  • Male
  • Middle Aged
  • Nigeria / epidemiology
  • Prevalence
  • Vision, Low / epidemiology*
  • Vision, Low / etiology
  • Vision, Low / prevention & control
  • Vision, Monocular