! Amblyopia is vision loss caused by suppression of a structurally normal eye due to strabismus, asymmetric refraction (anisometropia), or deprivation. Treatment becomes challenging if not caught by age 7, but half of all patients in the US are undetected and untreated until after it is too late, making it the leading cause of preventable vision loss. Rebion has developed retinal birefringence scanning (RBS) into a commercial product, the RBS-based Pediatric Vision Scanner (PVS), which detects amblyopia and strabismus with 94% accuracy, compared with 69% accuracy of non-RBS methods. However RBS-based scanning faces challenges ? including the need for costly moving parts and the presence of significant background noise necessitating background measurements ? that may limit widespread commercial acceptance of this technology. With prior Phase I NEI funding (EY 027633) Rebion has successfully built a new approach toward assessment of retinal birefringence that we call retinal birefringence imaging (RBI). Like RBS, this approach measures the polarization signature produced by the Henle nerve fibers at the center of fixation of the retina, thus objectively detecting ocular fixation, but it can be implemented with no moving parts and without the need for background measurements. Imaging are obtained in a fraction of a second (vs. 2.5 seconds of scanning required for an accurate RBS measurement.) The design also allows for future incorporation of a photoscreening channel for assessment of refractive error in synchrony with detection of amblyopia and strabismus. In this Phase II study, we will test the hypothesis that the performance of the RBI device can match the sensitivity, specificity, and accuracy of the commercially available PVS device in a large-scale clinical trial. The RBI device built with Phase I funding will be deployed with the Retina Foundation of the Southwest, and tested in both the enriched population of eye care clinics, as well as un-enriched populations of primary care clinics. The disease prevalence of primary care clinics will more closely mimic the disease prevalence of the general population, while the disease prevalence of eye clinics will allow the study to carry statistical significance in the most cost-effective use of NIH funds. Successful execution of project milestones will lead to an immediate transition to regulatory clearance with FDA and manufacturing with Rebion's contract manufacturer. This advance will greatly reduce expenses and complexities related to pediatric vision screening.
Rebion has developed a handheld, no-moving-parts device for providing quick, noninvasive detection of amblyopia and strabismus, the leading causes of preventable vision loss in children in the United States. Current methods, including Rebion's own Pediatric Vision Scanner (PVS), require complex scanning equipment that is prone to confounding error produced by ambient light or short attention spans. Clinical trials in this proposal will test the accuracy of this image-based method and compare it to comprehensive ophthalmic examinations and Rebion's own PVS.
