title: Prevalence of amblyopia among secondary school students in Calabar, south-south Nigeria.
abstract: OBJECTIVE
  To determine the prevalence of amblyopia among secondary school students in Calabar metropolis
  
  
  METHODS
  It was a cross-sectional study with subjects recruited by multi-stage simple random technique. A total of 1,241 students were eligible of which 1,175 were available for vision screening with Snellen's chart. Students whose visual acuities (VA) were <6/9 in at least one eye met the inclusion criterion for refraction. While those with visual acuities >6/9 in either eye were considered emmetropic. History, ocular alignments, anterior and posterior segment examinations were carried out. Students with best-corrected VA<6/9 in either of the eyes with no identifiable pathology were considered amblyopic. Data analysis was by SPSS 15.0 (2008)
  
  
  RESULTS
  Of the screened students, there were 535 males and 640 females (chi2 = 16.439, P=0.088). The age range was 9-21 years. One thousand nine hundred and four (93.1%) had VA6/9 in both eyes (i.e. 6/9 in each eye tested separately). Of the 81(6.9%) with VA 6/9 who meant the criterion for refraction, 61 (5.2%) were refracted to at least 6/9 in both eyes. The amblyopia prevalence was 0.3% (95% confidence interval [CI], 0.27 - 0.35) with no sex (P-value = 0.088) effects but showed statistical significance with age (chi-square, chi2 = 140.954, P-value = 0.000)
  
  
  CONCLUSIONS
  The prevalence of amblyopia in this study is relatively low compared to otherAfrican and non-African studies.
authors.affiliation: Department of Ophthalmology, University of Calabar Teaching Hospital, Calabar, Cross River State. favouredolu@yahoo.com
authors.forename: E O
authors.initials: EO
authors.lastname: Megbelayin
mesh_terms: D000293:Adolescent; D000328:Adult; D000550:Amblyopia / Q000453:epidemiology*; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D009549:Nigeria / Q000453:epidemiology; D015995:Prevalence; D013334:Students / Q000706:statistics & numerical data; D055815:Young Adult