Altered mechanical behavior and properties of the human anterior lens capsule after cataract surgery

Several studies have quantified the mechanics of the normal lens capsule, motivated in large part by the need to understand better the mechanism of accommodation. In addition to this principal physiologic function, the lens capsule also plays a significant clinical role by housing the prosthetic lens implanted during cataract surgery. This procedure alters dramatically the mechanical environment of the capsule, which may modulate the errant behavior of lens epithelial cells that leads to capsular contraction and deposition of non-native matrix proteins. Although much is known about histological alterations within the post-surgical capsule, little is known about the altered mechanics. We performed uniaxial mechanical tests on normal and post-surgical human anterior lens capsules and found, for the first time, that cataract surgery leads to a significant stiffening of the capsule nearest the capsulorhexis edge. These data promise to be important for developing predictive tools capable of elucidating interactions between the post-surgical capsule and implant.