AGING OF THE HUMAN CRYSTALLINE LENS AND ANTERIOR SEGMENT

Changes in the unaccommodated human crystalline lens were characterize d as a function of subject age for 100 normal emmetropes over the age range 18-70 yr by Scheimpflug slit-lamp photography. With increasing a ge, the lens becomes thicker sagittally, but since the distance from t he cornea to the posterior lens surface remains unchanged, this indica tes that the center of lens mass moves anteriorly and the anterior cha mber becomes shallower. Sagittal nuclear thickness is independent of a ge, but both anterior and posterior cortical thicknesses increase with age, shifting the location of the nucleus and the central sulcus in t he anterior direction. The amount of light scattered by the lens at hi gh angles, as represented by normalized and integrated lens densities from the digitized images, increases with increasing age in an exponen tial fashion. Similar relationships to age are observed for the major anterior zone of discontinuity (maximum density) and the central sulcu s (minimum density). The relationships of these results to accommodati on and presbyopia are discussed.