Micropulse vs. continuous wave transscleral cyclophotocoagulation in neovascular glaucoma

A Systematic Review of Cyclophotocoagulation Techniques: Continuous Wave Versus Micropulse for Glaucoma Treatment

Objectives

Micro-pulse cyclophotocoagulation (MP-CPC) represents the latest iteration of minimally invasive laser procedures aimed at reducing intraocular pressure (IOP) through the disruption of pigmented ciliary body epithelium. This systematic review aims to assess the efficacy and safety profile of the MP-CPC procedure in comparison to CW-CPC for the treatment of glaucoma.

Methods

We initiated a search on PubMed, ScienceDirect, and the Cochrane Library databases for studies that compared micro-pulse and traditional CW-CPC in terms of their efficacy and safety profiles. We employed medical subject headings terms and keywords such as "cyclophotocoagulation," "cyclodestructive," "photocoagulation," "CPC," "micropulse," "micro-pulse," and "glaucoma" within the timeframe from 2015 to 2023. We assessed the success rate, IOP reduction, antiglaucoma medications, and complications of MP-CPC and CW-CPC.

Results

We included six articles in this study, comprising two randomized controlled trials, three retrospective, and one prospective cohort, published between 2015 and 2023. Five out of six reported a significant reduction in IOP for both procedures with comparable success rates observed in MP-CPC compared to CW-CPC. One article reported an increase in IOP in MP-CPC. Both groups reported a decrease in the number of antiglaucoma medications, while one study reported an increase in medications in both MP-CPC and CW-CPC groups. Complication rates were lower in the MP-CPC group with two articles reporting a significant decrease compared to the CW-CPC group.

Conclusion

MP-CPC has shown promising results in the treatment of glaucoma in the adult population. With comparable results in IOP reduction and fewer instances of serious ocular complications, MP-CPC may open new possibilities for the use of cyclophotocoagulation procedures in the earlier stages of glaucoma. However, its efficacy in the pediatric population and for neovascular glaucoma remains less defined, thus warranting further studies to establish optimal laser parameters for different types of glaucoma and specific populations of glaucoma patients.

Clinical Outcomes of MicroPulse Transscleral Laser Therapy with the Revised P3 Delivery Device

Aim

To evaluate the success and safety of MicroPulse transscleral laser therapy (TLT) on intraocular pressure (IOP) reduction in adults with uncontrolled glaucoma using different total treatment durations, sweep velocities, and a number of sweeps utilizing the revised MicroPulse P3 delivery device.

Materials and methods

A single-center Institutional Review Board (IRB) approved multiple cohort studies of MicroPulse TLT with the revised MicroPulse P3 delivery device, which was conducted in 61 eyes from 40 adults with uncontrolled glaucoma. Eyes that received 50-second (GI, GII, and GIII) and 60-second (GIV, GV, and GVI) treatment applications between May and October 2020 were reviewed. Each hemisphere received a total of five, four, or three sweeps. The patient's IOP and glaucoma medications were monitored over 12 months follow-up. Qualified success was defined as an IOP of ≤21 mm Hg and/or reduction of ≥20% from baseline at 12 months, with no secondary glaucoma reinterventions. Complete success was defined as meeting the above criteria with no increase in glaucoma medications at 12 months. All eyes requiring a glaucoma surgical intervention were considered a failure.

Results

Qualified success was achieved in 83.6% of eyes, while complete success was achieved in 75.4% of eyes. In eyes receiving 50-second applications of five, four, or three sweeps (GI, GII, and GIII), 70, 90, and 91% achieved qualified success, respectively; in eyes receiving 60-second applications of five, four, or three sweeps (GIV, GV, and GVI), 78, 82, and 90% achieved qualified success, respectively. Within each subgroup, mean IOP reductions ranged from 32.8 to 49.4% and were statistically significant (p < 0.008). The failure rate was 16.4%, and at least one eye failed in each subgroup.

Conclusions

MicroPulse TLT with the revised MicroPulse P3 delivery device and relatively low total energy levels is safe and effective at lowering IOP. Efficacy appears to increase with longer treatment durations and slower sweep velocities, but statistical differences between age and clinical differences between baseline IOP measurements limit comparison between subgroups.

Clinical significance

There is a lack of literature evaluating the safety and IOP-lowering success of the revised MicroPulse P3 delivery device using different total treatment durations, sweep velocities, and number of sweeps.

How to cite this article

Checo LA, Dorairaj S, Wagner IV, et al. Clinical Outcomes of MicroPulse Transscleral Laser Therapy with the Revised P3 Delivery Device. J Curr Glaucoma Pract 2024;18(1):10-15.

Efficacy of Micropulse Laser Cyclophotocoagulation Therapy in Primary Angle Closure Glaucoma

PRCIS

In primary angle closure glaucoma (PACG), micropulse cyclophotocoagulation resulted in a significant reduction in intraocular pressure (IOP), and the number of antiglaucoma medications without any sight-threatening complications. However, the IOP lowering efficacy decreased over time.

PURPOSE

The purpose of this study was to evaluate the efficacy and safety of micropulse trans-scleral cyclophotocoagulation (MP-TSCPC) in PACG.

PATIENTS AND METHODS

Thirty-three phakic PACG eyes with patent laser peripheral iridotomy and IOP uncontrolled on maximum tolerable antiglaucoma medications (AGMs), scheduled for trabeculectomy, were given a trial of MP-TSCPC (810 nm laser, 2000 mw power for 180 seconds, 360 degrees). The primary outcome measure was a success at 1 year with IOP ≤18 mm Hg and ≤15 mm Hg with (qualified success) or without (absolute success) AGMs after a single session of MP laser. Secondary outcome measures were changes in pupillary diameter, visual acuity, central macular thickness, and subjective pain perception.

RESULTS

Thirty-two out of 33 PACG patients completed 12 months of follow-up. The mean age of patients was 54.7±8.9 years; male:female ratio was 1:1. The baseline IOP was 25.7±5.3 mm Hg, which reduced to 17.9±4.6 mm Hg at the end of 12 months (P<0.0001). Twenty eyes (62.5%) achieved qualified success, and 1 eye (3.125%) had absolute success at 12 months for IOP ≤18 mm Hg; 6 eyes (18.75%) had qualified success, and 1 eye (3.125%) had absolute success for IOP ≤15 mm Hg at 12 months follow-up. A significant reduction was also observed in the number of AGMs (4.4±0.8 at baseline to 2.9±1.1 at 12 months; P <0.0001). Five eyes (15.6%) received additional treatment-3 eyes (9.4%) requiring a subsequent filtering procedure, and 2 eyes (6.2%) requiring an additional MP-TSCPC session. No significant change in pupillary diameter (P=0.489) or central macular thickness (P=0.938) was noted at 12 months. There was a transient drop of visual acuity >2 lines in 1 patient due to cystoid macular edema, and no major postlaser complications were noted.

CONCLUSIONS

MP-TSCPC can be used as an interim procedure to reduce IOP in PACG eyes and delay the need for invasive surgery. Most patients require continued use of glaucoma medications, and target IOPs achieved are in the high teens.

Cyclophotocoagulation as a Minimally Invasive Treatment Option for Glaucoma

Historically, the complications and inadequate efficacy of prior cyclodestructive procedures limited their role in glaucoma management. Recent advances in treatment techniques and parameters for laser cyclophotocoagulation has expanded its role in today's glaucoma practice. This review summarizes the role of different cyclophotocoagulation techniques, including continuous wave transscleral cyclophotocoagulation and micropulse transscleral cyclophotocoagulation, in the management of glaucomatous optic neuropathy.

The efficacy and safety of micropulse transscleral laser treatment in glaucoma: a systematic review and meta-analysis

OBJECTIVE

Micropulse transscleral laser treatment (mTLT) is the latest alternative intraocular pressure (IOP) lowering approach for glaucoma patients. This meta-analysis aims to evaluate the efficacy and safety of mTLT and continuous wave transscleral cyclophotocoagulation (CW-TSCPC) for the treatment of glaucoma.

METHODS

We searched the PubMed, Embase, and Cochrane Library of Systematic Reviews databases from January 2000 to July 2022 to identify studies that, evaluated the efficacy and safety of mTLT in glaucoma. There were no restrictions regarding study type, patient age, or type of glaucoma. We analysed the reduction in IOP and the number of anti-glaucoma medications (NOAM), retreatment rates, and complications between mTLT and CW-TSCPC treatment. Publication bias was conducted for evaluating bias. This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA 2020) reporting guideline.

RESULTS

We identified 6 eligible studies of which only 2 RCTs and 386 participants with various types of glaucoma at different stages were ultimately included. The results revealed significant IOP decreases after mTLT up to 12 months and significant NOAM reductions at 1 month (WMD=-0.30, 95% CI -0.54 to 0.06), and 3 months (WMD=-0.39, 95% CI -0.64 to 0.14) in mTLT compared to CW-TSCPC. Moreover, the retreatment rates (Log OR=-1.00, 95% CI -1.71 to -0.28), hypotony (Log OR=-1.21, 95% CI -2.26 to -0.16), prolonged inflammation or uveitis (Log OR=-1.63, 95% CI -2.85 to -0.41), and worsening of visual acuity (Log OR=-1.13, 95% CI -2.19 to 0.06) occurred less frequently after mTLT.

CONCLUSION

Our results demonstrated that mTLT could lower the IOP until 12 months after treatment. mTLT seems to have a lower risk of retreatment after the first procedure, and mTLT is superior to CW-TSCPC with respect to safety. Studies with longer follow-up durations and larger sample sizes are necessary in the future.

TRIAL REGISTRATION NUMBER

INPLASY202290120.

The mechanism and therapeutic strategies for neovascular glaucoma secondary to diabetic retinopathy

Neovascular glaucoma (NVG) is a devastating secondary glaucoma characterized by the appearance of neovascular over the iris and the proliferation of fibrovascular tissue in the anterior chamber angle. Proliferative diabetic retinopathy (PDR) is one of the leading causes of NVG. Currently increasing diabetes population drive the prevalence rate of NVG into a fast-rising lane. The pathogenesis underlying NVG makes it refractory to routine management for other types of glaucoma in clinical practice. The combination of panretinal photocoagulation (PRP), anti-vascular endothelial growth factor (VEGF) injections, anti-glaucoma drugs, surgical intervention as well as blood glucose control is needed. Early diagnosis and aggressive treatment in time are crucial in halting the neovascularization process and preserving vision. This review provides an overview of NVG secondary to diabetic retinopathy (DR), including the epidemiology, pathogenesis and management, so as to provide a better understanding as well as potential therapeutic strategies for future treatment.

Surgical Treatment in Silicone Oil-Associated Glaucoma

Glaucoma is a vision threatening, not uncommon complication of eyes that have undergone pars plana vitrectomy with silicone oil endotamponade. Although most patients respond well to medical antiglaucoma therapy, there are refractory cases where surgery is required to control the intraocular pressure. This review, following a comprehensive literature search in the Medline database, aims to present the most important surgical techniques currently in use for glaucoma associated with silicone oil endotamponade and their indication depending on the mechanism of glaucoma. In cases of pupillary block, the presence of a patent iridotomy or iridectomy must be ensured, either by laser or surgically. When silicone oil is in excess and whenever the retinal status permits it, partial or complete removal of the silicone oil should be performed. Trabeculectomy has shown higher failure rates and more complications in these cases compared to other indications, so alternate methods are warranted. For very high intraocular pressures, glaucoma drainage devices and transscleral cyclophotocoagulation are the most used options, with good efficacy and safety profiles, although rarely they may have serious complications. The Ex-PRESS mini shunt has shown excellent results and lower rates of complications. For less important IOP elevations, minimally invasive glaucoma surgery and selective laser trabeculoplasty may be used, either alone or in conjunction with other methods.