MedicalResearch: What are the main findings of the study?
Answer: Commercially available automated screening devices assess refractive risk factors, not amblyopia or strabismus, resulting in under-referral of affected children and over-referral of healthy children to pediatric eye care professionals. The Pediatric Vision Scanner is a binocular retinal birefringence scanner that directly detects strabismus and amblyopia by analyzing binocular scans for the presence or absence of birefringence, which is characteristic of steady, bifoveal fixation. We found that the Pediatric Vision Scanner outperformed an automated, refractive error screener (SureSight Autorefractor) in a cohort of 300 patients (2-6 years) tested in a pediatric ophthalmology setting. Compared to the SureSight, the Pediatric Vision Scanner had significantly higher sensitivity and higher specificity in the detection of strabismus and amblyopia.
MedicalResearch: Were any of the findings unexpected?
Answer: The Pediatric Vision Scanner had been shown by the developer, Dr. David Hunter, and his colleagues to have high sensitivity and specificity in the detection of strabismus and amblyopia. However, this is the first independent study to compare the Pediatric Vision Scanner to a commercially available refractive screener (SureSight) in a large cohort of preschool children aged 2-6 years. The Pediatric Vision Scanner had very high sensitivity (97%) to strabismus and/or amblyopia, and significantly higher than refractive screening with the SureSight (70%). The Pediatric Vision scanner also had high specificity, with only a 13% false positive rate compared to the SureSight false positive rate of 38%.
MedicalResearch: What should clinicians and patients take away from your report?
Answer: The failure to detect amblyopia during early childhood, when treatment may be most effective, is a serious public health problem. Retinal birefringence scanning with the Pediatric Vision Scanner is a novel approach that provides the direct detection of strabismus and amblyopia, rather than the common approach of indirectly assessing refractive error risk factors. We should consider that preschool vision screening may be more efficient with a device that directly detects strabismus and amblyopia, not just the risk factors.
MedicalResearch: What recommendations do you have for future research as a result of this study?
Answer: Along with others, we recommend that vision screeners be judged on how accurately they identify children affected with the targeted conditions of strabismus and amblyopia, not how accurately they detect risk factors. Most children with risk factors will never develop strabismus of amblyopia. No known medical harm comes from lack of detection of nonamblyogenic refractive errors. Our data suggest that screening at regular intervals to provide early and accurate identification of children who develop strabismus or amblyopia, and referral of only affected children to eye care professionals may be a more effective approach. This strategy is in keeping with the 2013 AAPOS Vision Screening Committee recommendation that vision “screening should be viewed as a continuous process that occurs throughout visual development.”