Micropulse Cyclophotocoagulation: A Multicenter Study of Efficacy, Safety, and Factors Associated With Increased Risk of Complications

Abstract

Précis: Micropulse cyclophotocoagulation (MPCP) lowered intraocular pressure (IOP) in the short-term but nearly half required additional intervention. Mydriasis was the most common complication (11%); 15% lost ≥3 Snellen lines of acuity; 11% had persistent complications at last follow-up. Purpose: The purpose of this study was to evaluate the efficacy and complications of MPCP in a large series of patients with all stages of glaucoma. Design: Multicenter, retrospective chart review of patients from 3 clinical sites. Participants: One hundred sixty-seven eyes of 143 patients. Methods: MPCP was performed with 2000 mW energy, 31.3% duty cycle and 2 to 4 180-degree applications of 80 seconds duration each per treatment. The procedure was considered a failure if any of the following occurred: additional IOP lowering intervention, <20% IOP reduction from baseline at the last follow-up (with or without medication), or severe complications. Results: Mean age was 71 years, 53% were female, and 53% were Asian. 60% of eyes had POAG, 63% were pseudophakic, 38% had prior glaucoma surgery, and 51% had Snellen visual acuity (VA) of 20/40 or better. Mean follow-up time was 11.9±7.8 months. Mean IOP was 21.9±8.4 mm Hg before intervention, and 17.4±7.2 mm Hg at last follow-up (P<0.0001). There was no change in mean logMAR VA (P=0.0565) but 15% lost ≥3 Snellen lines of VA. The success rate was 36.5% (61/167 eyes) at last follow-up. The probability of survival by Kaplan-Meier analysis was 82%, 71%, and 57% at 3, 6, and 12 months after the procedure, respectively. The reasons for failure were additional intervention in 47%, inadequate IOP reduction in 14%, and severe complication in 1.8%. In a multivariable Cox proportional hazard model, female sex was associated with a 56% decrease in failure rate compared with males (P<0.0001), while a unit increase in baseline IOP corresponded with a 5.7% increase in failure rate (P<0.0001). If repeat MPCP was allowed then success rate increased to 58%. There were no complications in 73% (122/167) but 11% (18/167) had persistent complications at the last follow-up and half of these 18 eyes had decrease in VA of 1 to 6 Snellen lines. Asian race (odds ratio 13.5, P=0.0131) and phakic status (odds ratio 3.1, P=0.0386) were associated with higher odds of developing mydriasis, which was the most common complication. Conclusions: MPCP lowered IOP in the short-term but nearly half required additional IOP lowering intervention. Potential complications should be discussed in detail especially when the procedure is being considered for those with good VA and early stage disease.

An update on continuous‐wave cyclophotocoagulation (CW‐CPC) and micropulse transscleral laser treatment (MP‐TLT) for adult and paediatric refractory glaucoma

“…This method could have lead to cyclophotocoagulation, as the total laser application duration was greater than 3 s per site, which is longer than the commonly used transscleral cyclophotocoagulation, despite not using a continuous motion and, therefore, the thermal effect was lower than with the traditional technique. Retreatments: the literature on retreatment is limited. The studies with the highest retreatment rates (≥20%) were those in which the delivered energies were modest (<100 J) (Tan et al 2010; Aquino et al 2015; Elheifney et al 2019; Nguyen et al 2019; de Crom et al 2020; Radhakrishnan et al 2020; Tekeli & Köse 2020) and/or the mean preoperative IOP was too high (>30 mmHg) to reach the success endpoint after a single session (Tan et al 2010; Aquino et al 2015; Elheifney et al 2019; Jammal et al 2019; Preda et al 2020; Tekeli & Köse 2020). Tekeli & Köse (2020) have found a significantly higher retreatment rate in eyes with other types of secondary glaucoma than in eyes with POAG and PXG.…”

“…Less severe complications have been described such as persistent mydriasis in 1.6% (Kaba et al 2020), 3% (Nguyen et al 2019), 5% (Magacho et al 2019), 11% (Radhakrishnan et al 2020) and 15% of cases (Magacho et al 2020). Asian race (OR: 13.5, p = 0.0131) and phakic status (OR: 3.1, p = 0.0386) are associated with higher odds of developing mydriasis (Radhakrishnan et al 2020).…”

“…Less severe complications have been described such as persistent mydriasis in 1.6% (Kaba et al 2020), 3% (Nguyen et al 2019), 5% (Magacho et al 2019), 11% (Radhakrishnan et al 2020) and 15% of cases (Magacho et al 2020). Asian race (OR: 13.5, p = 0.0131) and phakic status (OR: 3.1, p = 0.0386) are associated with higher odds of developing mydriasis (Radhakrishnan et al 2020). The incidence of CME was less than 2% (Yelenskiy et al 2018; Garcia et al 2019; de Crom et al 2020; Radhakrishnan et al 2020) except in the study by Williams et al (2018) where it was 5.0% and in the two studies by Magacho et al where it was 6.7% (2019) and 6.0% (2020), respectively, probably due to long treatment durations.…”

Micropulse Transscleral Cyclophotocoagulation as Primary Surgical Treatment for Primary Open Angle Glaucoma in Taiwan during the COVID-19 Pandemic

“…Dorairaj et al [56] identified that myopic females with brown irises were more likely to develop this complication. Radhakrishnan et al [57] reported higher odds of persistent mydriasis in those of Asian descent (odds ratio = 13.07, p < 0.001) and in phakic eyes (odds ratio = 3.12, p = 0.014). Causes of this condition may be multifactorial, while the most widely accepted mechanisms are the occlusion of iris vessels and iris ischemia secondary to an acute elevation in IOP leading to ischemic atrophy of the iris sphincter, with consequent pupil dilation [56].…”

“…This observation eventually resolved within one month. Postoperative reversible mydriasis has been described in several studies [39,41,[55][56][57]. Dorairaj et al [56] identified that myopic females with brown irises were more likely to develop this complication.…”