Defects of vision through aphakic spectacle lenses.

The following defects of aphakic vision will be reviewed: (1) magnification, which causes false orientation (due to excessive overall magnification of aphakic spectacles, resulting in false depth, and false projection) and distortion (due to excessive peripheral magnification of aphakic spectacles, resulting in pincushioning and concave contracture of the peripheral visual field); (2) swim; (3) image aberrations due to defects of focus through the periphery of aphakic spectacle lenses, resulting from radial astigmatism, curvature of image plane, spherical aberration, coma, and chromatic aberration; (4) restricted peripheral visual field due to small lens size, the roving ring scotoma, and the unrefracted area outside the field of view of aphakic spectacle lenses; (5) near vision problems; (6) weight, thickness, and cosmetic appearance of aphakic eyeglasses; and (7) inaccurate spectacle prescription due to faulty measurement of vertex distance, inaccurate lens duplication, pantoscopic tilt, turning of head during refraction, and rotation of eye during refraction.