Photoscreening for amblyogenic factors by public health personnel: the Eyecor Camera System

This pilot study was designed to assess the ability of a photoscreening camera to detect amblyogenic factors such as high refractive error, anisometropia, media opacities and strabismus in children, compared to the standard vision screening techniques employed by the local state public health screening personnel.

Public health personnel in Illinois used the Eyecor prototype to the current commercially available MTI PS-100 photoscreening camera (manufactured by Medical Technology Inc.) to screen 127 non-dilated subjects, ages 7 months to 20 years (mean age, 6 years), for amblyogenic factors. All participants were concurrently subjected to the "standard" vision screening employed routinely by state public health personnel. The study participants included a group of normal inner-city children and one group of special-needs children. The normal children came from both a public school and a private school. The special-needs children included a group of children from a state-run school for the deaf and hard-of-hearing and a separate group of children attending a multi-disciplinary Easter Seals clinic.

In the population of normal children, the mean sensitivity and specificity for the observers using the Eyecor Camera system was 81% and 83% with a mean positive predictive value of 83%, and a mean negative predictive value of 55%. Standard vision screening techniques employed by public health service certified vision screeners had a sensitivity of 88%, a specificity of 91%, a positive predictive value of 67% and a negative predictive value of 97% in the same subjects. In the population of special-needs children with hearing impairment and developmental delay, the mean sensitivity and specificity for the observers using the Eyecor Camera system was 74% and 82% with a mean positive predictive value of 69% and a mean negative predictive value of 85%. Standard vision screening techniques employed by public health service certified vision screeners had a sensitivity of 100%, a specificity of 55%, a positive predictive value of 62% and a negative predictive value of 100% in the same subjects. (See Table 1)

This study shows that the Eyecor Photoscreening Camera is useful in screening normal children for amblyogenic factors. Photoscreening was at least as effective as standard screening methodologies performed by certified vision screeners as required by state public health policy. In addition, photoscreening is particularly useful in testing those children "unscreenable" by conventional vision screening procedures.