Glaucoma progression analysis after MPCPC laser: Long term follow up

Abstract

Purpose : Micropulse Transscleral Cyclophotocoagulation (MPCPC) is a tissue-sparing technology that delivers repetitive short bursts of energy (on-cycle) separated by rest periods (off-cycle). It allows non pigmented ciliary tissue to remain below coagulation threshold during off-cycle, minimizes adjacent tissue thermal damage and lowers complications. This retrospective study evaluated IOP lowering effect and glaucoma progression in patients who underwent MPCPC (MP3, Iridex Corporation) and had no previous incisional glaucoma surgery.

Methods : Forty seven eyes of 32 patients were treated with MPCPC at Mayo Clinic FL from July 2016 to July 2017 and were followed for a minimum of 24 months afterwards. Laser energy used was 2000 mW, duty cycle of 31.3% and mean laser duration of 80 seconds for each 180° hemisphere. Success criteria was defined as ≥20% IOP reduction, BCVA loss ≤ 2 lines and no glaucoma reoperation. Two glaucoma specialists analyzed progression based on HVF (EMGT criteria) and OCT (RNFL thickness). Data was obtained as Mean ± SD and percentage. Wilcoxon signed-rank test and t-test were used to compare pre and postoperative data. P value <0.05 was considered significant.

Results : Mean baseline IOP was 22.51 ± 6.67 mmHg. After 24 months, mean IOP was 14.80 ± 4.38 mmHg (28.09 ± 32.5% reduction - P <0.0001) and 68.08% of eyes showed an IOP reduction of ≥ 20%. Mean preoperative glaucoma medications were 2.68 ± 1.23 and after 24 months reduced to 1.34 ± 0.73 (1.40 ± 1.09 reduction – P <0.0001) with 72.34% of eyes showing reduction of ≥ 1 medication. The mean preoperative BCVA changed from 0.205 ± 0.209 to 0.166 ± 0.169 LogMAR at 24months.
Out of four patients who progressed, three initially met success criteria and none required glaucoma reoperation at 24 months. However at a mean of 29.75 months all patients showed progression and were treated accordingly. Those four patients were myopic, pseudophakic and three (75%) had prior SLT in the same eye.

Conclusions : MPCPC is a safe and effective procedure for all glaucoma types. Patients with myopia, pseudophakia, pseudoexfoliation and previous SLT failure should be closely monitored; despite achieving success criteria initially, they showed late progression. Future MPCPC prospective studies may analyze severe glaucoma progression using 10-2 HVF to detect paracentral visual defects.

This is a 2020 ARVO Annual Meeting abstract.

 

Patient demographic and baseline findings

 

Survival curve showing glaucoma progression after MPCPC