title: Comparing Visual Acuity Measured by Lea Symbols and Patti Pics.
abstract: BACKGROUND
  There is little data validating most illiterate eye charts. Lea Symbols®, however, have been well validated in numerous studies. In this study, we compare the assessment of visual acuity employing both the Lea Symbol hanging wall Early Treatment Diabetic Retinopathy Study (ETDRS)-style chart and a similar Patti Pics® ETDRS-style chart in order to determine whether the two charts provide clinically similar data.
  
  
  METHODS
  We tested the vision of the right eyes of fifty-two consecutive patients. Patients were cooperative children or adults between the ages of 3 and 88 years (mean 58 years). We alternated the order of the chart used first. Patients were also categorized by age and by visual acuity.
  
  
  RESULTS
  The visual acuities measured by the two charts were equal for 83% of the measurements (forty-three eyes). In 8% of eyes (four eyes), the visual acuity measured with the Lea Symbols was one line better than that measured by the Patti Pics; in 9% of eyes (five eyes), the acuity from the Patti Pics chart measured one line better than the Lea Symbols. There was no difference in measurements for either adults or children or among patients with different visual acuities.
  
  
  CONCLUSIONS
  We believe this study will serve to provide useful information when choosing an eye chart to assess visual acuity in a clinic setting. Patti Pics performed similarly to Lea Symbols in adults and children tested in a multi-specialty ophthalmology practice. We suspect that it would also perform similarly in the primary care and school settings.
authors.affiliation: From the Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland;
authors.forename: Eric L
authors.initials: EL
authors.lastname: Singman
authors.affiliation: From the Family Eye Group, Lancaster, Pennsylvania and.
authors.forename: Noelle S
authors.initials: NS
authors.lastname: Matta
authors.affiliation: From the Department of Biostatistics, Bloomberg School of Public Health, Baltimore, Maryland.
authors.forename: Jing
authors.initials: J
authors.lastname: Tian
authors.affiliation: From the Family Eye Group, Lancaster, Pennsylvania and.
authors.forename: David I
authors.initials: DI
authors.lastname: Silbert
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000550:Amblyopia / Q000175:diagnosis* / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015351:Vision Screening / Q000379:methods*; D014792:Visual Acuity; D055815:Young Adult
keywords: Lea Symbols®; Patti Pics®; pediatric ophthalmology; pediatric vision screening; visual acuity