The efficacy of photoscreening for amblyopiagenic factors in a high risk population

Abstract

Background: Amblyopia is the leading cause of monocular "legal" blindness in children and young adults, affecting 3% to 5% of the population. Factors producing amblyopia can be detected through a complete eye examination. Although it is important to treat children at risk for amblyopia as early as possible, appropriate screening methods for severely impaired individuals are lacking. The purpose of this study was to assess the ability of a photoscreening camera to detect amblyopiagenic factors (strabismus, unequal refractive error, and media opacities) in a group of disabled children, who were currently unscreenable with standard methodology.

Methods: Fifty-four high risk individuals, 6-20 years in age, were evaluated for amblyopiagenic factors using the MTI photoscreening camera, pre- and post-cycloplegia. The "gold standard" for comparison was a concurrent complete eye examination, including ocular health, visual acuity estimation, motility, ophthalmoscopy and clinical cycloplegic refractive error determination. Criteria for a "failure" on the clinical examination included myopia greater than -1.00 diopters (D), hyperopia greater than +3.00 D (2-6 years) and greater than +2 D (over 6 years), astigmatism greater than 1.5 D, unequal refractive error greater than 1.5 D, any strabismus, or any media opacity.

Results: Fifty- four individuals with disabilities, deemed untestable by standard vision screenings, were evaluated. The number of children with amblyopiagenic factors by complete cycloplegic ophthalmologic examination was 30 (55%) and by photoscreening was 25 (46%). Using the MTI photoscreener, the sensitivity was determined to be 83% with a specificity of 79%. The positive and negative predictive values of photoscreening were 83% and 79% respectively.

Conclusions: The MTI photoscreener can detect such amblyopiagenic factors as high refractive error, strabismus, unequal refractive error, and significant media opacity. Photoscreening is an excellent way of obtaining valid vision screening with limited patient cooperation. Using photoscreening data, proper referrals can be made and prioritized for disabled individuals.