Contrast sensitivity in children with strabismic and anisometropic amblyopia. A study of the effect of treatment.

The contrast threshold of sinusoidal gratings of varying contrast and frequency was examined in children with amblyopia due to strabismus or anisometropia. In strabismic amblyopia the contrast sensitivity is depressed for only a limited band of high spatial frequencies. In anisometropic amblyopia depression of the contrast sensitivity function (CSF) was found over the whole frequency range. The CSF could not be predicted from the visual acuity measurements in amblyopic eyes due to strabismus, whereas a rough correlation was observed in anisometropia. During occlusion treatment of the dominant eye in anisometropia the visual acuity and the contrast sensitivity function of the amblyopic eye improved in parallel. The study indicates that the abnormalities in spatial vision are different in amblyopia due to strabismus or anisometropia during childhood. Determination of the contrast sensitivity function seems to be an additional tool besides acuity measurements to document changes of visual function during treatment of amblyopia.