Two-flash photorefraction in screening of amblyogenic refractive errors.

A selection of amblyopic (n = 14) and nonamblyopic (n = 18) children with different ametropias, anisometropias, and astigmatisms was photorefracted without cycloplegia by two-flash photorefraction (T-FP) in which refractions in both horizontal and vertical meridians of both eyes are measured simultaneously. The results were compared to conventional cycloplegic retinoscopy in a blind study. Significant amblyogenic conditions, such as hyperopic anisometropias of more than 1.0 diopter (D), high ametropias, or astigmatism and strabismus cases of 2 degrees to 3 degrees or more are detectable. The technique provides a simple and useful tool for mass screening of infants. The sensitivity of the method for detecting amblyopia seems to be at least as high as in visual checking. Media opacities are recordable, and a permanent document is obtained.