In vitro alteration of human lens curvatures by radial stretching

The shapes of two human lenses of different ages (27 and 46 years old) were altered by applying a stretching force to the ciliary muscle. The force was in the outward radial direction and was produced by an electronically driven stretching instrument which is described. The lenses were photographed for different degrees of stretch, and their anterior and posterior curvatures analysed. All curves could be fitted to second order polynomial functions. The posterior curvatures did not appear to alter with stretch and were almost identical in both lenses. Although the anterior surfaces of both lenses changed with application of the stretching force, that of the younger lens showed a considerably greater alteration. Most changes in sagittal thickness occurred with radial stretching of up to 1.0 mm. The results of this work are compared to those of other studies on both functional and in vitro lenses.