Background: Monocular autorefraction is a newly available technology for visio n screening that has been advocated to test young children. Such devices automat ically determine the refractive state of each eye, but cannot directly detect am blyopia or strabismus. Objective: To compare the results of a commercially avail able monocular autorefractor (SureSight;Welch Allyn Medical Products, Skaneatele s Falls, NY) with findings from a comprehensive eye examination for significant refractive error, strabismus, and amblyopia. Methods: Children 5 years and young er who were new patients attending a pediatric ophthalmology clinic were tested with the monocular autorefractor without dilation and underwent a comprehensive eye examination that included dilation. Main Outcome Measures: The proportion of children who could be tested and the sensitivity and specificity of the screeni ng. Results: Of the 170 children enrolled (age,< 3 years, n = 80; age range, 3- 5 years, n=90), 36%had abnormal eye examination findings. Most (84%) children 3 years or older could be tested compared with 49%of the children younger than 3 years (P<.001). Among those who were testable, for children younger than 3 yea rs the sensitivity was 80%(95%confidence interval [CI], 44%-97%) and the sp ecificity was 41%(95%CI, 24%-61%). For children aged 3 to 5 years, the sens itivity was 88%(95%CI, 68%-97%) and the specificity was 58%(95%CI, 43%- 71%). Conclusions: Our findings suggest that screening children aged 3 to 5 yea rs with monocular autorefraction would identify most cases of visual impairment but would be associated with many false-positive results. For children younger than 3 years, testability was low and results were nonspecific. Background: Monocular autorefraction is a newly available technology for visio n screening that has been advocated to test young children. Such devices automat ically determine the refractive state of each eye, but can not directly detect am blyopia or strabismus. Objective: To compare the results of Welch Allyn Medical Products, Skaneatele Falls, NY) with findings from a comprehensive eye examination for significant refractive error, strabismus, and amblyopia. Methods: Children 5 years and young er who were new patients attending a pediatric ophthalmology clinic were tested with the monocular autorefractor without dilation and underwent a comprehensive eye examination that incorporated dilation. Main Outcome Measures: The proportion of children who could be tested and the sensitivity and specificity of the screen. ng: Of the 170 children enrolled (age, <3 years, n = 80; age range, 3-5 years, n = 90), 36% had abnormal eye Most (84%) children 3 years or older could be tested compared with 49% of the children younger than 3 years (P <.001). Among those who were testable, for children younger than 3 yea rs the sensitivity was (95% confidence interval [CI], 44% -97%) and the sp ecificity was 41% (95% CI, 24% -61%). For children aged 3 to 5 years, (95% CI, 68% -97%) and the specificity was 58% (95% CI, 43% - 71%). Conclusions: Our findings suggest that screening children aged 3 to 5 yea rs with monocular autorefraction would identify most cases of visual impairment but would be associated with many false-positive results. For children younger than 3 years, testability was low and results were nonspecific.