title: Grating visual acuity with Teller cards compared with Snellen visual acuity in literate patients.
abstract: OBJECTIVE
  To determine the usefulness of Teller Acuity Cards for detecting three levels of vision deficit, the cutoff for amblyopia (20/40 or poorer), vision impairment (20/70), or legal blindness (20/200).
  
  
  METHODS
  We compared grating visual acuity with the Teller cards with Snellen visual acuity (our gold standard) in 69 literate patients with amblyopia or other cause of vision loss in a prospective masked study.
  
  
  RESULTS
  Teller card visual acuity and distance Snellen visual acuity correlated significantly (r = .508, P < .001); however, Teller card visual acuity explained only 26% of the variation in distance Snellen visual acuity. Teller card visual acuity had a low sensitivity for detecting vision deficit of 20/40 or poorer (58%), vision deficit of 20/70 or poorer (39%), or legal blindness (24%), but somewhat more accurately reflected near Snellen visual acuity than distance visual Snellen acuity. Teller cards had a higher positive predictive value--80% for 20/70 visual acuity and 43% for legal blindness, as determined by near Snellen visual acuity. Specificity of Teller cards was 88% for detecting visual acuity loss of 20/70 and 98% for legal blindness. Negative predictive value of Teller cards for detecting visual acuity loss of 20/70 was 50% and for legal blindness was 71%.
  
  
  CONCLUSIONS
  Teller Acuity Cards may underestimate the presence of amblyopia of all types, legal blindness, and a specified level of vision impairment (20/70). Even in the presence of normal visual acuity measurements with Teller cards, significant visual loss as assessed by standard Snellen optotypes may be anticipated in many patients.
authors.affiliation: University of Wisconsin Hospital and Clinic, Madison, USA.
authors.forename: B J
authors.initials: BJ
authors.lastname: Kushner
authors.forename: N J
authors.initials: NJ
authors.lastname: Lucchese
authors.forename: G V
authors.initials: GV
authors.lastname: Morton
mesh_terms: D000293:Adolescent; D000328:Adult; D000550:Amblyopia / Q000175:diagnosis / Q000503:physiopathology; D016022:Case-Control Studies; D002648:Child; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013285:Strabismus / Q000175:diagnosis / Q000503:physiopathology; D014786:Vision Disorders / Q000175:diagnosis*; D014787:Vision Tests / Q000295:instrumentation*; D014792:Visual Acuity / Q000502:physiology*