Abstract
Purpose: :
The objective of this study is to compare the safety and efficacy of conventional and micropulse diode laser transscleral cyclophotocoagulation (TCP) in the treatment of refractory glaucoma. Specifically, it aims to compare the intraocular pressure (IOP) lowering effects and the incidence of ocular complications associated with each.
Methods: :
Patients with refractory glaucoma having IOP of >21 mmHg on maximal tolerated medical therapy with or without previous surgical intervention and visual acuity of 6/60 or worse were randomized into two groups, conventional diode or micropulse diode TCP. Conventional TCP setting was 1.5 - 2Watt (W), 2second(s) duration per pulse, with an average of 20 -28 pulses per eye delivering 60 -112 Joules (J) per treatment. Micropulse TCP was set at 2 W, 100s pulse envelop with 0.5ms ON and 1.1ms OFF delivering 62.6J per treatment. After the procedure, patients were reviewed at intervals of 1 day, 1 week, 1 month, 3 months, 6 months and 18 months. At every visit, best corrected visual acuity (BCVA), detailed anterior segment examination, IOP, number & type of medication/s were noted. Re-treatment was done in patients where IOP reduction was 30% from baseline and IOP < 21mmHg, with or without topical IOP lowering medications. Rate of complications was the measure of safety.
Results: :
Fifty-one (51) patients were treated. Twenty-five eyes were randomized to conventional TCP and 26 to micropulse TCP. Mean follow-up period was 17months ± 1.6 for both groups. Baseline IOP in the conventional group was 37.9 ± 11.4 and 41.6 ± 15.1 in the micropulse group. At 18 months follow-up, IOP was recorded at 20.9 ± 13.8 mmHg (conventional) resulting to 48.2 ± 30.9% drop vs. 19.8 ± 4.7 mmHg (micropulse) amounting to 49.8 ± 12.2% IOP reduction (p = 0.07 Student’s t test). The number of medications pre-laser was 1.9 ± 0.9 for conventional and 2.1 ± 1.0 for micropulse. There was no significant difference in the number of eye drops (1.2) in both arms during the final follow-up. Success rate was 78% for conventional TCP and 85% for micropulse TCP. In conventional TCP, there were 5 cases of hypotony, 5 with prolonged uveitis, 1 had phthisis bulbi, 4 developed scleral thinning and 7 cases of loss of BCVA. Only 1 eye suffered scleral thinning in micropulse TCP treated eyes.
Conclusions: :
Micropulse TCP has equal efficacy in terms of IOP lowering compared to conventional TCP. It offers better safety profile with fewer complications after treatment.
Clinical Trial: :
http://www.clinicaltrials.gov NCT00349414
Keywords: laser • ciliary body • clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials