Aphakia: perceptual and refractive problems of spectacle correction.

The perceptual variations due to removal of the crystalline lens and the employment of powerful plus spectacle lenses are described. These include refractive change, distortion, magnification, limitation of the visual field, peripheral vision, sensitivity of light and changes in the required convergence. The technique for satisfactory refraction of the aphakic eye is discussed and the elements leading to error such as vertex distance and pantoscopic tilt are considered. Other factors necessary for understanding the refraction such as the apparent accommodative range and the limitations affecting field charting are also covered. Method of securing binocularity via contact lens-spectacle combinations for monocular cases, and the need for rehabilitative procedures conclude this treatment.