The purpose of this study was to determine the size and shape of infant eyes having a unilateral congenital cataract. Fourteen infants presenting consecutively with a unilateral congenital cataract were studied. Ages ranged from 1.3 to 6 months (mean 3.7 months). Corneal curvature ranged from 43.00 to 49.50 D (mean 45.6 D). Refractive error at the corneal plane ranged from +23.50 to +34.00 D (mean +28.07 D). The axial length ranged from 16.49 to 20.09 mm (mean 18.41 mm). Microcornea was found in eight infants. There was rapid growth in eye size from normal neonatal dimensions. No significant relation was found among the following: corneal curvature and age; refractive error and age; axial length and age or presence of microcornea; and corneal curvature and refractive error. Corneal vault may be an important factor in fitting contact lenses to aphakic infants. Contact lenses for infants should be designed based on the dimensions of the infant eye.