This study compared the PlusoptiX A12 to a comprehensive ophthalmic investigation. This was a three-month study of 219 (438 eyes) subjects with a mean age of 72 months. The A12 referred 101 of 219 (46%) patients for potential amblyopia. Ophthalmic investigation found 87 (40%) with amblyopia or amblyopia risk factors. On comparison of the A13 to ophthalmic investigation, testability rate was 84.47%, sensitivity of 93.02%, specificity of 84.96%, false positives of 9.13%, false negatives of 2.74%, positive predictive value of 80% and negative predictive value of 94.96%. The authors conclude the A13 is a user-friendly and time-efficient screening device with high sensitivity for detecting refractive amblyopia risk factors. Further increase in sensitivity may be possible with combination of A12 and the alternate cover test.