We studied the effect of cataract extraction and intraocular lens (IOL) implantation (14 unilateral and 2 bilateral cases) on eye growth in 16 children. Visual acuity, refractive power, axial length, corneal curvature, and anterior chamber depth in both the operated and unoperated eyes were measured before and after surgery. The operated eyes tended to become myopic (maximum, -11.00 diopters). However, though the axial length of two eyes increased significantly after surgery, there was no significant difference between the postoperative increase in axial length in the operated and in the unoperated eyes. The anterior chambers of the unoperated eyes tended to be deeper. We suggest that the tendency to become myopic in the operated eyes occurred because, as axial length increases with growth, the proportion occupied by the vitreous body, ie, the part posterior to the IOL, also increases.