Final Version of the Distance Randot Stereotest: Normative data, reliability, and validity

Abstract

Measurement of distance stereoacuity may be useful in assessing strabismic patients, especially those with intermittent exotropia. We developed the Distance Randot Stereotest as an easily administered quantitative test for distance stereoacuity in children. By using a prototype, we reported testability, validity, and normative data. Here we report normative and validity data for the final, commercially available version of the test. We administered both the Prototype and the Final Version Distance Randot Stereotest to 156 normal volunteers (2-40 years of age) and 77 strabismic patients (4-62 years of age). Test-retest data were collected for the Final Version. Normative Final Version scores were similar to those obtained with the Prototype; 96% were < or = 100 arcsec. Test-retests were identical in 82% and within one disparity level in 100%. Final Version scores were correlated with Prototype scores (rs = 0.64, p < 0.001). Among strabismic patients, 62.3% had abnormal stereoacuity; those with normal scores had incomitant or intermittent deviations. Nil stereoacuity was found in 27 patients, confirmed in 90.9% of retests; 17 had measurable stereoacuity, confirmed in 96.3% of retests. Patients with constant strabismus were more likely to have nil stereoacuity than patients who had intermittent strabismus (95% vs 12.2%). Distance Randot scores from normal subjects have low variability within each age group and high test-retest reliability. There is little overlap between Distance Randot scores from normal control and strabismic patients. The Distance Randot Stereotest is a sensitive measurement of binocular sensory status that may be useful in monitoring progression of strabismus and/or recovery after strabismus surgery.