Long-Term Outcomes of Micropulse Transscleral Cyclophotocoagulation in Primary Open-Angle Glaucoma and the Effect of Preoperative Intraocular Pressure

Abstract

Purpose : To compare 1-year outcomes of micropulse transscleral cyclophotocoagulation (MP-CPC) in terms of IOP, number of IOP-lowering agents, and surgical success between primary open-angle glaucoma (POAG) patients with high and low preoperative (preop) IOP.

Methods : A retrospective chart review was performed of POAG patients undergoing MP-CPC at John H. Stroger Hospital of Cook County, Chicago, IL from 2015 to 2019. The study included 125 eyes from 99 patients. IOP and the number of IOP-lowering agents were recorded at each follow-up visit through 12 months. High and low IOP was defined as >21 and ≤21 mmHg, respectively. Kaplan-Meier survival analyses were conducted with failure defined as IOP ≤ 5 or > 21 or a reduction ≤ 20% on two consecutive study visits without additional glaucoma intervention. Eyes that succeeded with additional intervention were classified as a qualified success. Logrank tests were used to compare survival curves between groups.

Results : Out of 125 eyes, 62 (49.6%) were classified as high preop IOP and 63 (50.4%) were classified as low preop IOP. Fifty-two eyes (41.6%) had previous glaucoma intervention, which was not associated with surgical success in survival analysis (p=0.58). After 12 months, mean IOP was reduced from 30.7±7.6 to 15.7±6.0 (p<0.0001) in eyes with high preop IOP and from 18.0±2.1 to 14.9±3.7 (p=0.0004) in those with low preop IOP (Fig. 1). The number of IOP-lowering agents decreased in eyes with both high (p=0.02) and low (p=0.002) preop IOP with no difference between groups. The probability of success was significantly higher for eyes with high preop IOP (p=0.01). After 12 months, success probabilities were 43.5% and 28.7% for eyes with high and low preop IOP, respectively (Fig. 2). Qualified success probabilities after 12 months were 49.2% and 30.6%. The odds ratio for surgical failure after 12 months was 2.2 (p=0.04) for patients with low compared with high preop IOP. When additional intervention during the follow-up period was not considered, the odds ratio rose to 2.8 (p=0.006).

Conclusions : MP-CPC is effective at decreasing IOP and the need for IOP-lowering agents in POAG patients. However, patients with preop IOP > 21 had a significantly higher probability of achieving surgical success after 12 months than those with preop IOP ≤ 21. Preop IOP may be useful in predicting successful MP-CPC outcomes.

This is a 2020 ARVO Annual Meeting abstract.