Test-retest reliability of the Saladin card

Test-retest reliability is a measure of the confidence that results will be identical when the same patient is measured with an instrument in the same manner on more than one occasion.

Using the Saladin Near Point Balance Card--an instrument designed to test various near visual findings, including visual acuity, phorias, AC/A ratios, dynamic retinoscopy, fixation disparity, associated phorias, fixation disparity curves, as well as accommodative and vergence facilities--28 first- and second-year optometry students were evaluated on two occasions by one clinician, with the tests separated by approximately two weeks. Subjects were required to demonstrate 20/20 distance visual acuity and at least 100 sec of arc stereopsis. A total of 38 findings were compared, which included near horizontal and vertical phorias, associated phoria, and fixation disparity curves. Twenty-two findings were performed through the subjects' habitual prescription and the remaining findings were taken through the lens indicated by MEM retinoscopy.

The purpose of this study was to investigate whether the Saladin Near Point Balance Card had acceptable test-retest reliability. If reliability can be demonstrated, this instrument could be used in clinical situations to diagnose visual departures from normal.

All but two of the 38 tests performed demonstrated acceptable test-retest reliability. Coefficients of repeatability and 95% limits of agreement were calculated. The Saladin Near Point Balance Card demonstrated acceptable test-retest reliability.

Since it is light-weight, portable, easily and quickly administered, and reliable, the Saladin card can be used by clinicians who are performing screenings or examinations in non-clinical situations, such as nursing homes or schools.