BackgroundAs instrument-based pediatric vision screening technology has evolved, the American Association for Pediatric Ophthalmology and Strabismus (AAPOS) has developed uniform guidelines (2003, updated 2013) to inform the development of devices that can detect specified target levels of amblyopia risk factors (ARFs) and visually significant refractive error. Clinical experience with the established guidelines has revealed an apparent high level of over-referral for non-amblyopic, symmetric astigmatism, prompting the current revision.MethodsThe revised guidelines reflect the expert consensus of the AAPOS Vision Screening and Research Committees.ResultsFor studies of automated screening devices, AAPOS in 2021 recommends that the gold-standard confirmatory comprehensive examination failure levels include anisometropia >1.25 D and hyperopia >4.0 D. Astigmatism >3.0 D in any meridian and myopia < −3 D should be detected in children <48 months, whereas astigmatism >1.75 D and myopia < −2 D should be detected after 48 months. Any media opacity >1 mm and manifest strabismus of >8Δ should also be identified. Along with performance in detecting ARFs and refractive error, validation studies should also report screening instrument performance with regard to presence or absence of amblyopia. Instrument receiver operating characteristic curves and Bland-Altman analysis are suggested to improve comparability of validation studies.ConclusionsExamination failure criteria have been simplified and the threshold for symmetric astigmatism raised compared to the 2013 guidelines, whereas the threshold for amblyogenic anisometropia has been decreased. After age 4 years, lower magnitudes of symmetric astigmatism and myopia are also targeted despite a low risk of amblyopia, because they can influence school performance and may warrant consideration of myopia prevention therapy. As instrument-based pediatric vision screening technology has evolved, the American Association for Pediatric Ophthalmology and Strabismus (AAPOS) has developed...