Inhibition of secondary cataracts by cryolysis of lens epithelium in rabbits

In an attempt to inhibit secondary cataract formation by destroying the subcapsular lens epithelium, a defined amount of freeze was applied to the anterior capsule of one eye of 16 New Zealand white rabbits just prior to a planned extracapsular cataract extraction of both eyes using phacofragmentation. The rabbits were sacrificed eight weeks after surgery and the secondary cataracts were dissected from the eyes. The degree of secondary cataract formation was evaluated by two independent observers and grading systems. Overall, 14 of 16 rabbits, or 88%, had a significant (P less than .01) reduction of secondary cataract in the treated eye as compared to the control eye. This study demonstrates that freezing of the subcapsular lens epithelium prior to a planned extracapsular cataract extraction in rabbits can significantly diminish secondary cataract formation. However because of the present difficulty in controlling the extent of the freeze to the surrounding ocular tissues with current cryoprobes, this procedure is not yet applicable in humans.