MAY 03, 2016
Pediatric Ophth/Strabismus
A new automated binocular screener demonstrates good sensitivity and excellent specificity for identifying children at risk for strabismus-related amblyopia.
The Spot Vision Screener (Welch Allyn) is a handheld device designed for use in schools and pediatric offices. As a binocular vision screener, it identifies children for strabismus referral based on the device’s measurement of “gaze.” It is held approximately 3 feet away from the patient, who is engaged by a display of twinkling lights and sounds. The device then produces a report detailing pupillary diameter, ocular alignment, estimated binocular refraction and referral recommendations.
In this prospective study, investigators assessed the Spot’s ability to detect manifest strabismus of more than 8Δ in primary position, the standard threshold outlined in the 2013 guidelines of the American Association for Pediatric Ophthalmology and Strabismus (AAPOS) for detection of amblyopia risk factors by automated vision screeners. Patients who were referred by the Spot for gaze were included as test positives. Those found to have constant strabismus of more than 8Δ in primary position by the physician were considered referral positive.
Of the 444 children who underwent screening, 93 (20.9%) met the referral-positive threshold for strabismus criteria on examination by a pediatric ophthalmologist. The sensitivity of the Spot to detect AAPOS-threshold strabismus was 77.17%, whereas the specificity, 93.73%. Positive predictive value was 76.34%; negative predictive value 94.0%.
The authors estimate that in the general pediatric population, the Spot would have a positive predictive value of 29.77% and a negative predictive value of 99.17%.
The authors note that children with intermittent strabismus could suffer false negatives or false positives, depending on how the child appears during testing. Additionally, they found that the device is not designed to detect smaller degrees of horizontal strabismus.