Improved Outcomes for Transscleral Cyclophotocoagulation Through Optimized Treatment Parameters

Purpose: To compare outcomes of transscleral diode cyclo-photocoagulation with the treatment parameters used. Patients and Methods: This was a retrospective chart review of a random, 50% sample of diode procedures using the G-probe over 10 years for uncontrolled glaucoma. The main outcome measure was intraocular pressure (IOP) reduction by 20% and final IOP <= 21mm Hg. Results: In 236 eyes (persons) treated by 5 glaucoma specialists, most eyes had severe glaucoma, with 75% having < 20/200 acuity. Median follow-up was 2.7 years. In eyes receiving only 1 treatment, IOP success criterion was met in 72% (129/180). Success was significantly related to power per delivery and median total joules per treatment (successes = 135 J, failures = 98 J; P = 0.0009), but not to number of deliveries, nor to extent of circumference treated. Greater success was associated with 3 or 4 second duration per delivery, power level based on audible cues, and firm pressure on the sclera. Using a standard 2000 mW, 2 seconds, 20 deliveries in each eye had the lowest success (49%). Of those with no preoperative pain, 40 persons (57%) had no postoperative pain, whereas 20 reported pain of 1-3/10 (29%). Phthisis occurred in 7 eyes (3%), 5 of which had severe secondary eye disease. Nine eyes had no light perception preoperatively, whereas 50 eyes were no light perception at last follow-up, many after additional surgeries for other conditions. Conclusions: Diode cyclophotocoagulation achieved reasonable IOP lowering, often without severe postoperative pain or complication. Greater success was achieved when audible effects were used to tailor the power settings to individual responses. Diode treatments with no intraoperative effect adjustment or using standardized protocols may not achieve optimal success.