Real Depth vs Randot Stereotests

Purpose: To compare the performance of real depth and Randot stereotests in strabismic and nonstrabismic patients. Design: Observational case series. Methods: Stereoacuity was tested in 182 patients with a variety of strabismic conditions, using the Frisby-Davis 2 (FD2) distance stereotest, the near Frisby (nF) (both real depth tests), the Preschool Randot (nR), and Distance Randot (dR) tests (both based on Polaroid vectographs). Results: Patients appreciated finer disparities with the nF test than the nR test at near and with the FD2 test than the dR test at distance. Conclusions: The type of stereotest influences measurable thresholds, and the results from different tests are not interchangeable. The choice of test should depend on the question being asked; nF and FD2 would be appropriate for determining presence or absence of stereopsis and best measurable stereopsis. The more rigorous Randot tests would be appropriate for determining subtle changes.