title: Comparison of the Retinomax and Palm-AR Auto-Refractors: a pilot study.
abstract: OBJECTIVE
  To compare the performance of two handheld auto-refractors, the Retinomax and the Palm-Automatic Refractometer (Palm-AR), for detecting significant vision disorders in pre-school children.
  
  
  METHODS
  Children attending Philadelphia PreKindergarten Head Start were screened with the Retinomax and Palm-AR and underwent a gold standard eye examination. The results of cycloplegic retinoscopy, cover testing, and visual acuity were used to classify children as having normal vision or one of four conditions: amblyopia, strabismus, significant refractive error, and reduced visual acuity. Pass/fail criteria for each instrument were selected to maximize overall sensitivity (with specificity set at 90% and at 94%) for detecting targeted disorders. Comparisons of sensitivities between the auto-refractors were performed using the exact McNemar test.
  
  
  RESULTS
  Testability was >99% for both instruments. Test time was similar for the two instruments (median 2 min; p=0.10). At 90% specificity, the sensitivity for detection of one or more targeted conditions was 74% for the Palm-AR and 78% for the Retinomax. At 94% specificity, the sensitivity for detection of one or more targeted conditions was 66% for both the Palm-AR and the Retinomax. At 90% specificity, the sensitivity for detecting significant refractive error was 84% for both auto-refractors, and at 94% specificity, the sensitivity was 76% for the Palm AR and 75% for the Retinomax. There were high correlations between the instruments for sphere (r=0.85) and cylinder (r=0.88) power. The mean difference between instruments was -0.13 diopters (D) (95% limit of agreement: -2.28 to 2.02) for sphere, and -0.15 D (95% limit of agreement: -0.89 to 0.59) for cylinder.
  
  
  CONCLUSIONS
  In this pilot study, the Retinomax and Palm-AR appear comparable with respect to testability, sensitivity, and specificity. There was strong agreement in readings of sphere and cylinder indicating that they may perform similarly in a screening setting.
authors.affiliation: The Pennsylvania College of Optometry at Salus University, 8360 Old York Road, Elkins Park, Pennsylvania 19027-1598, USA. eciner@salus.edu
authors.forename: Elise
authors.initials: E
authors.lastname: Ciner
authors.forename: Ashanti
authors.initials: A
authors.lastname: Carter
authors.forename: Gui-Shuang
authors.initials: GS
authors.lastname: Ying
authors.forename: Maureen
authors.initials: M
authors.lastname: Maguire
authors.forename: Marjean Taylor
authors.initials: MT
authors.lastname: Kulp
mesh_terms: D000550:Amblyopia / Q000175:diagnosis; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D009184:Mydriatics; D010865:Pilot Projects; D012030:Refractive Errors / Q000175:diagnosis; D042261:Retinoscopes / Q000592:standards; D042262:Retinoscopy / Q000379:methods*; D012680:Sensitivity and Specificity; D013285:Strabismus / Q000175:diagnosis; D014786:Vision Disorders / Q000175:diagnosis; D015351:Vision Screening / Q000295:instrumentation* / Q000379:methods*; D014792:Visual Acuity
chemical_list: D009184:Mydriatics