title: Population-based assessment of sensitivity and specificity of a pinhole for detection of significant refractive errors in the community.
abstract: BACKGROUND
  Measurements of refractive errors through subjective or automated refraction are not always possible in rapid assessment studies and community vision screening programs; however, measurements of vision with habitual correction and with a pinhole can easily be made. Although improvements in vision with a pinhole are assumed to mean that a refractive error is present, no studies have investigated the magnitude of improvement in vision with pinhole that is predictive of refractive error. The aim was to measure the sensitivity and specificity of 'vision improvement with pinhole' in predicting the presence of refractive error in a community setting.
  
  
  METHODS
  Vision and vision with pinhole were measured using a logMAR chart for 488 of 582 individuals aged 15 to 50 years. Refractive errors were measured using non-cycloplegic autorefraction and subjective refraction. The presence of refractive error was defined using spherical equivalent refraction (SER) at two levels: SER greater than ± 0.50 D sphere (DS) and SER greater than ±1.00 DS. Three definitions for significant improvement in vision with a pinhole were used: 1. Presenting vision less than 6/12 and improving to 6/12 or better, 2. Improvement in vision of more than one logMAR line and 3. Improvement in vision of more than two logMAR lines.
  
  
  RESULTS
  For refractive error defined as spherical equivalent refraction greater than ± 0.50 DS, the sensitivities and specificities for the pinhole test predicting the presence of refractive error were 83.9 per cent (95% CI: 74.5 to 90.9) and 98.8 per cent (95% CI: 97.1 to 99.6), respectively for definition 1. Definition 2 had a sensitivity 89.7 per cent (95% CI: 81.3 to 95.2) and specificity 88.0 per cent (95% CI: 4.4 to 91.0). Definition 3 had a sensitivity of 75.9 per cent (95% CI: 65.5 to 84.4) and specificity of 97.8 per cent (95% CI: 95.8 to 99.0). Similar results were found with spherical equivalent refraction greater than ±1.00 DS, when tested against the three pinhole-based definitions.
  
  
  CONCLUSIONS
  Refractive error definitions based on improvement in vision with the pinhole shows good sensitivity and specificity at predicting the presence of significant refractive errors. These definitions can be used in rapid assessment surveys and community-based vision screenings.
authors.affiliation: Allen Foster Community Eye Health Research Centre, Gullapalli Pratibha Rao - International Centre for Advancement of Rural Eye care, Baltimore, Maryland, USA; Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, USA; Vision Cooperative Research Centre, Sydney, Australia. srioptom@lvpei.org.
authors.forename: Srinivas
authors.initials: S
authors.lastname: Marmamula
authors.forename: Jill E
authors.initials: JE
authors.lastname: Keeffe
authors.forename: Saggam
authors.initials: S
authors.lastname: Narsaiah
authors.forename: Rohit C
authors.initials: RC
authors.lastname: Khanna
authors.forename: Gullapalli N
authors.initials: GN
authors.lastname: Rao
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D015994:Incidence; D007194:India / Q000453:epidemiology; D008297:Male; D009907:Optometry / Q000379:methods*; D011159:Population Surveillance; D012029:Refraction, Ocular; D012030:Refractive Errors / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D012680:Sensitivity and Specificity; D015351:Vision Screening / Q000379:methods*; D014787:Vision Tests / Q000295:instrumentation*; D055815:Young Adult
keywords: pinhole; refractive errors; screening; sensitivity; specificity