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Comparison of the Retinomax and Palm-AR Auto-Refractors: A Pilot Study

The Vision in Preschoolers (VIP) Study Group

doi: 10.1097/OPX.0b013e3182192658
Original Article

Purpose. 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.

*The members of the VIP Study Group Writing Committee are listed in the Acknowledgments.

Received September 16, 2010; accepted February 8, 2011.

The Pennsylvania College of Optometry at Salus University 8360 Old York Road Elkins Park, Pennsylvania 19027-1598 e-mail: eciner@salus.edu

© 2011 American Academy of Optometry