Abstract
Purpose:
To supply the demand for an automated screening device that reliably detects amblyopia risk factors (strabismus and defocus) in infants and children.
Methods:
We developed a novel Pediatric Vision Screener (PVS) that uses wave-plate-enhanced retinal birefringence scanning for strabismus detection, essentially independent of an eye’s corneal birefringence, and double-pass focus detection using a bull’s eye photodetector. The performance of the novel PVS in detecting 1) strabismus and 2) defocus was demonstrated and tested in one young emmetrope (age 29) and one presbyopic, myopic volunteer (age 67) by acquiring data while 1) subjects fixed centrally and then in various off-center directions, up to 1.5° paracentrally; 2) trial lenses were placed in front of the subject’s eye, stepping through the point of best focus.
Results:
Our performance testing of the novel PVS confirmed presence of unique frequency components in the signal with central fixation. The width of the spatially mapped distribution of these unique frequency components at half peak maximum (FWHM) was approximately +/- 0.75° (1.5 prism diopters), in accordance with the theoretic accuracy of strabismus detection with the novel design. Our feasibility tests of focus detection suggest that the device has the potential to detect spherical focus within 1.00 diopter based on the focus curve’s FWHM of approximately +/- 1.00 diopter.
Conclusions:
The novel PVS shows promise as a reliable, automated strabismus/defocus screening tool for infants and children at risk for amblyopia. We started pilot testing with older cooperative children and adults, including well-characterized strabismic/anisometropic subjects, to establish threshold settings for pass/fail signal levels. Future studies with finalized threshold settings will determine device performance in less cooperative subjects, especially infants and young children, followed by large independent clinical trials.
Keywords: 709 screening for ambylopia and strabismus •
723 strabismus: diagnosis and detection •
688 retina