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SB Barone, A Kim, WL Ottar-Pfeiffer, SI Holgado, WE Scott, PY Tong; Screening for Amblyopia in Preverbal Children with Photoscreening Photographs. Improved Guidelines for Photograph Grading. . Invest. Ophthalmol. Vis. Sci. 2002;43(13):2667.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To improve the sensitivity and specificity of vision screening through the refinement of interpretation of photographs taken by the Medical Technology and Innovations (MTI) Inc. Photoscreener. Background: The MTI PhotoScreener is a commercially available Polaroid film-based instrument designed for pediatric vision screening for refractive error, strabismus, lens opacity, or other abnormalities. An accompanying instruction manual details the use of the camera and the interpretation of most photographs. Methods: The clinical data and the photographs of ∼1300 children from two previous studies were analyzed for photographic characteristics which can improve early detection of amblyopiogenic states. Pupil diameter was prospectively correlated with ambient light levels. Results: We report three modifications to improve the sensitivity and specificity of photoscreening. First, when astigmatic error is noted, a duplicate photograph should be taken to demonstrate reproducibility of the photographic findings. Bright crescents in one axis, from off-axis fixation, can masquerade as astigmatic error. Second, when lens opacity is suspected, requiring the consistent appearance in two photoscreening images would eliminate false positives from mucous build-up or corneal drying. Third, larger pupillary diameter is associated with superior sensitivity of detection of hyperopia. We report the correlation of pupillary diameter with ambient light levels and recommend low ambient light levels produce larger pupil sizes. Conclusions: The utility of the MTI PhotoScreener is improved by both reducing the number of children inadvertently referred for examination and increasing the number of children with disease identified. This can be accomplished through the requirement of reproducibility of aberrant features in two independent images and low ambient light levels to increase pupil diameter during screening.
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