Age-related response of human lenses to stretching forces.

Five human lenses of varying ages were subjected to radial stretching forces which mimic the action of the ciliary muscle in vivo. Although the number of lenses was small, it was found that the human lens becomes more resistant, with age, to radial stretching forces and that lenses over the age of 50 years showed very little response to stretch. In prepresbyopic lenses, stretching has a greater effect on the shape of the anterior surface than it does on the shape of the posterior surface. The five lenses studied showed individual variations in lens size and shape and a trend to increased curvature with age, particularly marked for the anterior surface.