PRESBYOPIA AND THE OPTICAL-CHANGES IN THE HUMAN CRYSTALLINE LENS WITHAGE

Lenses from 27 human eyes ranging in age from 10 to 87 years were used to determine how accommodation and age affect the optical properties of the lens, A scanning laser technique was used to measure focal leng th and spherical aberration of the lenses, while the lenses were subje cted to stretching forces applied through the ciliary body/zonular com plex, The focal length of all unstretched lenses increased linearly wi th increasing age. Younger lenses were able to undergo significant cha nges in focal length with stretching, whereas lenses older than 60 yea rs of age showed no changes in focal length with stretching, These dat a provide additional evidence for predominantly lens-based theories of presbyopia. Further, these results show that there are substantial op tical changes in the human lens with increasing age and during accommo dation, since both the magnitude and the sign of the spherical aberrat ion change with age and stretching, These results show that the optica l properties of the older presbyopic lens are quite different from the younger, accommodated lens. (C) 1998 Elsevier Science Ltd.