Aim: To establish the range of normal stereoacuity thresholds and evaluate the diagnostic reliability of stereoacuity tests in preschool-aged children.
Methods: 1606 children, aged 24-72 months, had detailed eye examinations and stereoacuity testing. Lang-Stereotest II (LangII) was attempted on all children, Stereo Smile Stereoacuity II Test (SSST) was conducted on children aged < 30 months and on older children who could not complete the Randot Preschool Stereoacuity Test (RPST). The RPST was conducted on children aged ≥ 30 months and on some younger children who passed both the LangII and SSST.
Results: Modes for the age groups 24-47 months and 48-72 months were: 200 arcsec for both age groups with the LangII test; 120 arcsec and 60 arcsec, respectively, with the SSST; 100 arcsec and 60 arcsec, respectively, with the RPST. Age-adjusted areas under the curve for detecting amblyopia, strabismus and anisometropia were: for the LangII test, 0.72, 0.68 and 0.60, respectively; for the SSST, 0.73, 0.80 and 0.57, respectively; for the RPST, 0.92, 0.82 and 0.73, respectively.
Conclusions: Normative data for the LangII, RPST and SSST stereoacuity tests were determined for children aged 24-72 months. Sensitivity and specificity at individual disparity levels for detecting anisometropia, amblyopia and strabismus were also determined for RPST and SSST. Using area under age-adjusted receiver operating curves, the RPST was found to be the most reliable in detecting ocular conditions compared with the LangII and SSST tests.