Improved Outcomes for Transscleral Cyclophotocoagulation Through Optimized Treatment Parameters

Purpose: To compare outcomes of transscleral diode cyclophotocoagulation 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 reduction by 20% and final IOP ≤21▒mm 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 one 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 joules, failures=98 joules; 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/delivery, power level based on audible cues, and firm pressure on the sclera. Using a standard 2000 milliwatt, 2 second, 20 deliveries in each eye had the lowest success (49%). Of those with no preoperative pain, 40 persons (57%) had no postoperative pain, while 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 (NLP) preoperatively, while 50 eyes were NLP at last followup, many after additional surgeries for other conditions. Conclusions: Diode cyclophotocoaguation 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.