Abstract
Purpose:
The Pediatric Vision Scanner (PVS) directly detects strabismus and amblyopia by analyzing binocular scans for the presence or absence of birefringence that, due to the organization of the radially arranged Henle fibers, is characteristic of steady, bifoveal fixation. In an initial study of patients tested in a pediatric ophthalmology office setting, the PVS had 98% sensitivity and 87% specificity for detection of strabismus and amblyopia. (Jost et al., AAPOS 2013) Here we report an intermediate evaluation of PVS sensitivity, specificity, and accuracy for a preliminary cohort of children screened in a pediatric primary care setting.
Methods:
60 children (2-6y) were enrolled. In addition to screening with the PVS, children were screened with the SureSight™ Autorefractor. Each test yielded a recommendation of “pass” or “refer.” All children received a gold-standard comprehensive ophthalmic exam by a pediatric ophthalmologist who was masked to the screening results.
Results:
At the gold-standard exam, 4 children were identified as having strabismus and/or amblyopia; 56 had normal exams. Three children were uncooperative for testing with the PVS and 7 could not be tested with SureSight™. Both the PVS and SureSight™ referred all 4 children with strabismus and/or amblyopia. Overall accuracy of the PVS was 90%. The PVS passed 47 of 53 children with no strabismus or amblyopia (89% specificity; 95%CI: 78-99%). In comparison, overall accuracy of the SureSight™ was 74%. The SureSight™ referred 14 of 49 children with no strabismus or amblyopia; i.e., the SureSight™ had significantly more false positives than the PVS (z=2.19; p=0.029; 71% specificity; 95%CI: 55-88%).
Conclusions:
In this ongoing study of the PVS in a pediatric primary care setting, results were comparable to the 87% specificity reported previously for a large cohort (n=250) tested in an ophthalmology practice with high prevalence of strabismus and amblyopia. In a pediatric primary care setting, the PVS had higher specificity and accuracy than the SureSight™, resulting in fewer over-referrals of children with no strabismus or amblyopia. Preschool vision screening may be more efficient with a device that directly detects strabismus and/or amblyopia.
Keywords: 709 screening for ambylopia and strabismus •
417 amblyopia •
722 strabismus