Micropulse versus Slow Coagulation Transscleral Cyclophotocoagulation in Refractory Glaucoma: A Randomized Clinical...

To compare the efficacy and safety of micropulse transscleral cyclophotocoagulation (MP-TSCPC) and slow coagulation transscleral cyclophotocoagulation (SC-TSCPC) in patients with refractory glaucoma followed for 12 months.

A parallel, double-arm, single-center, double-masked, randomized clinical trial.

Eighty eyes of 80 patients with refractory glaucoma.

Participants were randomly assigned (1:1) to receive either MP-TSCPC or SC-TSCPC. Micropulse transscleral cyclophotocoagulation was delivered using 2W of laser power applied in a sweeping motion over 320 seconds (31.3% duty cycle). Slow coagulation transscleral cyclophotocoagulation was performed with 1.25-1.5W continuous-wave laser applied with discrete spots for 4 seconds per spot across 3 quadrants (6 to 7 applications per quadrant). Patients and the examiner were masked for the procedure.

The primary outcome was mean intraocular pressure (IOP) reduction from baseline. Secondary outcomes included reduction in the number of antiglaucoma medications, complete and qualified success rates (defined as ≥20% IOP reduction from baseline and final IOP between 6 and 18 mmHg, without or with medications, respectively), and incidence of postoperative complications.

At 12 months, MP-TSCPC reduced IOP from 31.5 ± 9.2 to 15.0 ± 8.7 mmHg (P < 0.001); SC-TSCPC reduced IOP from 32.9 ± 9.0 to 12.6 ± 7.3 mmHg (P < 0.001), with no statistical difference in the final mean IOPs between the 2 arms (P = 0.12). The SC-TSCPC group showed a significantly greater mean IOP reduction than the MP-TSCPC group: 20.3 ± 10.2 mmHg (61% reduction) vs. 16.5 ± 11.7 mmHg (52% reduction), respectively (P = 0.03). Complete success was achieved in 29.7% patients in MP-TSCPC group and 33.3% in SC-TSCPC group (P = 0.64), while qualified success rates were 70.3% and 66.6%, respectively (P = 0.71). Complications were more frequent in SC-TSCPC (58.9%) than MP-TSCPC (35.1%) (P = 0.02) and included hypotony (20.5% SC-TSCPC vs. 0% MP-TSCPC, P < 0.005), vision loss (32.5% SC-TSCPC vs. 17.5% MP-TSCPC, P = 0.118), and phthisis bulbi (5.1% SC-TSCPC vs. 0% MP-TSCPC, P = 0.494). A multivariate analysis indicated that preoperative IOP >30 mmHg (hazard ratio [HR] = 2.269; 95% confidence interval: 1.014-5.077; P = 0.046) and IOP >15 mmHg at postoperative day 30 (HR = 2.477; 95% confidence interval: 1.106-5.548; P = 0.027) were independent predictors of surgical failure.

Both MP-TSCPC and SC-TSCPC effectively reduced IOP. Slow coagulation transscleral cyclophotocoagulation was associated with a greater mean IOP reduction but with a higher incidence of complications. Eyes with preoperative IOP >30 mmHg or IOP >15 mmHg at 30 days may be at greater risk for failure after these procedures.

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