[The tensile strength of human zonule and its alteration with age (author's transl)].

A series of 91 cryoextractions was performed on autopsy material. The scleral section was placed near to the chamber angle and was nearly circumferential (about 330 degrees). Cornea and adjacent sclera could be flapped over this way, and did not interfere with a straightforward lens extraction. The pupil was medically dilated. A cryoprobe was fixed to a specially constructed scale, and frozen to the anterior pole of the lens. Its weight was counterbalanced by a plastic water container at the other end of the scale. The extraction was performed by filling additional water into the counterbalancing container. The statistical evaluation of the results showed a very significant dependence of the average tensile strength on age. However, a considerable standard deviation was found throughout all ages. The nutritional state of the autopsy bodies and the time interval between death and start of the measurement had no significant influence. The differences between right and left eyes were also not significant, as could be expected. The methodological error remained small. Age proved to be an unreliable indicator for the tensile strength of the zonule. All results apply to clear lenses. We known from clinical experience that the tenacity of the zonule may also be different in the various types of cataract.