Screening infant vision with paraxial photorefraction.

Early screening for refractive errors is highly desirable. Techniques for doing this must be usable with noninstructable subjects (infants), noninvasive, and relatively easy to use. Photorefraction has been used to examine infants' refractive status. However, unless cycloplegia is used, the results can be difficult to evaluate, inasmuch as the subject's plane of focus is not known. This paper describes a photorefraction system that is being used for routine screening of young infants, without cycloplegia and without using highly skilled personnel. The major innovation is the systematic presentation of attractive targets at distances that present a range of demands to accommodation. Changes in the fundal reflections, seen in the photographs taken as the infant views the different targets, can be interpreted unequivocally to identify severe myopia and hyperopia, anisometropia, heterotropia, and anisocoria. The results can also be quantified and are compared with retinoscopic refractions.