Clinical Services

Diode laser cycloablation for uncontrolled glaucomas

Introduction:

When trabeculectomy or glaucoma drainage tube (seton) has failed to control glaucoma, then the treating physician may consider cycloablation (ablation or destruction of the ciliary body which produces the aqueous fluid). Because cycloablation involves permanent destruction of the ciliary body, it is usually the last line of treatment for uncontrolled glaucoma. Before the advent of laser, this was done using a cryoprobe (freezing probe) to freeze the ciliary body (cyclocryotherapy). This was often an uncomfortable procedure and was also associated with significant complications, including inflammation and loss of vision. Starting in the 1990’s, cyclocryotherapy was largely replaced by a laser procedure called CycloPhotoCoagulation or CPC). At the University of Iowa, a portable diode laser is used to perform CPC under a local (retrobulbar) anesthesia as an outpatient surgery. CPC usually takes less than 30 minutes to perform, including the anesthesia.

Cyclophotocoagulation (CPC) is a useful procedure for a refractive glaucoma which cannot be controlled by medications and other surgeries. The success rate for CPC is in the range of 60-70%, and it can be repeated if needed. The recovery period is usually 4-6 weeks. The follow up visits are not as intensive as the filtering surgery, and this may offer advantage to some patients. Post-operatively, the eye is treated with tapering regimen of anti-inflammatory steroids. There are a number of potential complications associated with CPC, although less than those of cyclocryotherapy. Because CPC can be associated with decrease in vision post-operatively, CPC is commonly reserved for patients who already have reduced vision from either glaucoma or other causes pre-operatively. CPC is also associated with increased inflammation, bleeding, and hypotony (low IOP usually below 5 mmHg). Hypotony is a particularly feared complication of CPC because it is often difficult to raise the IOP after a permanent destruction of the ciliary body. Fortunately, it occurs more rarely than with cyclocryotherapy.