Use of bipolar diathermy to prevent posterior capsule opacification(1)

To determine the feasibility of using directed bipolar diathermy to eliminate or reduce the formation of new cortical lens material following phacoemulsification in a rabbit model.

Department of Research & Development, Bausch & Lomb Surgical, and Department of Ophthalmology, St. Louis University, St. Louis, Missouri, USA.

A rabbit model for posterior capsule opacification (PCO) was used. A continuous curvilinear capsulorhexis was performed followed by phacoemulsification to remove cortical lens material. In 2 experimental groups, modified bipolar instruments were used to apply diathermy to residual lens epithelial cells using an intracapsular or extracapsular method of application. Postoperative clinical examinations were at 1, 3, and 7 days and then weekly up to 60 days. Selected animals were followed for a longer period. Capsule integrity was evaluated by measuring the pressure required to rupture the capsule in similarly treated porcine eyes.

Diathermy prevented PCO in 4 of 4 eyes in the intracapsular treatment group and 4 of 5 in the extracapsular group. Eyes remained free of new lens cortex for the life of the animal, which was as long as 18 months. New cortical material was detected after 35 days in 1 animal in the extracapsular group. Mean time for the formation of observable cortical material was 29 days +/- 5 (SD) in the control animals. Physical measurements did not detect a reduction in capsule integrity with diathermy treatment. The extracapsular treatment method resulted in fewer iris complications.

Directed diathermy has the potential to eliminate secondary cataract formation with minimal damage to collateral tissues.