Refractive error in Nigerian adults: prevalence, type, and spectacle coverage

Christian Ezelum, Hessom Razavi, Selvaraj Sivasubramaniam, Clare E Gilbert, Gudlavalleti V S Murthy, Gabriel Entekume, Tafida Abubakar, Nigeria National Blindness and Visual Impairment study group

Research output: Contribution to journalArticlepeer-review

48 Citations (Scopus)


Purpose. To provide data on prevalence and types of refractive error and the spectacle-wearing rate among adults in Nigeria and the degree to which the need for distance correction could be met by off-the-shelf spectacles.

Methods. Multistage, stratified, cluster random sampling with probability proportional to size was used to identify a nationally representative sample of 15,027 persons aged ≥40 years. Distance vision was measured using a reduced logMAR tumbling-E chart. All participants underwent autorefraction, and those with presenting acuity of <6/12 in one or both eyes had their corrected acuity measured and underwent detailed clinical examination to determine the cause.

Results. Included in the survey were 13,599 (89.9%) of the 15,122 persons aged ≥40 years who were enumerated. Uncorrected refractive error was responsible for 77.9% of mild visual impairment (<6/12–6/18), 57.1% of moderate visual impairment (<6/18–6/60), 11.3% of severe visual impairment (<6/60–3/60), and 1.4% of blindness (<3/60). The crude prevalence of myopia (≤0.5 D) and high myopia (≤5.0 D) were 16.2% and 2.1%, respectively. Spectacles could improve the vision of 1279 (9.4%) and 882 (6.5%) participants at the 6/12 and 6/18 level, respectively, but only 3.4% and 4.4% of these individuals wore spectacles to the examination site. Approximately 2,140,000 adults in Nigeria would benefit from spectacles that improved their vision from <6/12 to ≥6/12. More than a third of the need could be met by low-cost, off-the-shelf spectacles.

Conclusions. Uncorrected refractive errors are an important cause of visual impairment in Nigeria, and services must be dramatically improved to meet the need.
Original languageEnglish
Pages (from-to)5449-5456
Number of pages8
JournalInvestigative Ophthalmology & Visual Science
Issue number8
Early online date17 Feb 2011
Publication statusPublished - 22 Jul 2011


  • adult
  • age distribution
  • aged
  • aged, 80 and over
  • astigmatism
  • eyeglasses
  • female
  • health services needs and demand
  • health surveys
  • humans
  • hyperopia
  • male
  • middle aged
  • myopia
  • Nigeria
  • prevalence
  • refraction, ocular
  • sex distribution
  • visual acuity
  • visually impaired persons


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