Field testing of the plusoptiX S04 photoscreener

To evaluate the diagnostic accuracy of the plusoptiX S04 digital photoscreener in a school screening program.

Between 2006 and 2007, 1343 information pamphlets/consent forms were sent to all junior kindergarten students in a local school district. Assistants from a local public health unit photographed 307 children. Of these, 271 children received an independent ophthalmic examination by a physician. Photographic results were compared with the those of the ophthalmic examination. Amblyopia risk factors were defined as anisometropia >1 D (sphere or cylinder), astigmatism >1.25 D, myopia >3 D, hyperopia >3.5 D, any manifest strabismus, and any media opacity.

Photographic and examination results agreed in 94% of cases. Sensitivity in detecting amblyopia risk factors was 83%; specificity was 95%. The positive and negative predictive values were 73% and 97%, respectively. The untestable/unusable rate was 1%.

These results compare favorably with a previously reported (but no longer available) digital photoscreening camera and are superior to results obtained with other off-axis photoscreening devices that require human interpretation. On the basis of these results, in a real-world screening program, the camera would falsely refer 4% of those screened and would fail to correctly refer 2%. The accuracy of the plusoptiX S04 camera in detecting amblyopia risk factors appears sufficiently high to consider its further deployment in a widespread school screening program.