title: Comparison of visual acuity charts identifying visual impairment among older people outside the eye clinic.
abstract: OBJECTIVE
  Evaluate the construct validity and describe sensitivity, specificity and predictive value of two short charts of visual acuity (VA) and examine whether these can identify and detect signs of visual impairment among older people.
  
  
  METHODS
  The study included 43 persons, >65 years, with age related eye disease, living in their own homes. An ophthalmologist assessed the individuals' VA at an eye clinic with the 5 m KM chart. A research assistant assessed individuals' VA by the 1 m KM chart and the Visual Acuity Screening Test in their home environment.
  
  
  RESULTS
  All persons with a VA level of <0.5 were correctly identified by both instruments. The instruments have good positive and negative predictive values for the 1 m KM chart (73% and 100%) and for the Visual Acuity Screening Test (69% and 100%). The construct validity between the instruments was good, but the assessment at the eye clinic assessed the participants as having higher VA level.
  
  
  CONCLUSIONS
  Both instruments have good construct validity, considering they were carried out in poorer lighting conditions and a good predictive value for screening out VA levels <0.5. The 1 m KM chart showed the best agreement with the 5 m KM chart.
authors.affiliation: Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Sweden. lisbeth.claesson@neuro.gu.se
authors.forename: Lisbeth
authors.initials: L
authors.lastname: Claesson
authors.forename: Johanna
authors.initials: J
authors.lastname: Blomstrand
authors.forename: Kajsa
authors.initials: K
authors.lastname: Eklund
authors.forename: Kristina
authors.initials: K
authors.lastname: Eriksson
authors.forename: Synneve
authors.initials: S
authors.lastname: Dahlin-Ivanoff
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000554:Ambulatory Care Facilities; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D014786:Vision Disorders / Q000175:diagnosis*; D015351:Vision Screening / Q000295:instrumentation / Q000379:methods*; D014787:Vision Tests / Q000295:instrumentation / Q000379:methods*; D014792:Visual Acuity; D019987:Persons with Visual Disabilities