Prevention of posterior capsule opacification with the CO2 laser

BACKGROUND AND OBJECTIVE: Posterior capsule opacification (PCO) is a common complication after cataract extraction, despite the modern surgical techni ques and lenses being used for this procedure. Its prevention challenged ma ny investigators, because the current treatment of choice, capsulotomy with Nd:YAG laser, is associated with sight-threatening complications. In the p resent study, the authors investigated two approaches of preventing PCO usi ng the CO2 laser. MATERIALS AND METHODS: A 15-W CO2 laser with a 17- or 18-gauge hollow probe was used on 20 sheep eyes and 14 rabbit eyes. Lens extraction was done by phacoemulsification. In the equatorial treatment study, the anterior chambe r was filled with either air or a viscoelastic substance, and laser burns w ere applied to the equator of the lens capsule and to the peripheral anteri or capsule to destroy the epithelial cells. In the capsulotomy study, a pri mary posterior capsulotomy was created by delivering 1 to 3 laser shots to the capsule behind an implanted intraocular lens (IOL). RESULTS: The CO2 laser was satisfactory in sheep eyes after filling the ant erior chamber with air. In rabbit eyes, however, it was technically impract ical to work with air. Using a viscoelastic material to maintain the anteri or chamber, the hollow probe of the CO2 laser becomes plugged up and theref ore is unable to affect the ocular tissue. However, by combining viscoelast ic and air pumping, both the destruction of the lens epithelial cells and t he creation of a central posterior opening behind a capsular-fixated IOL wa s repeatedly achieved. CONCLUSION: Using the CO2 laser for destruction of lens epithelial cells an d the creation of controlled posterior capsulotomy is feasible and practica l. A different design of the probe (closed gauge) is required to enable it to operate clinically in a fluid or viscoelastic environment.