Clinical Outcomes of Micropulse Transscleral Cyclophotocoagulation in Patients with a History of Keratoplasty

Mechanism and treatment of secondary glaucoma after corneal transplantation: a review

Corneal transplantation is a common treatment for corneal diseases. Secondary glaucoma after corneal transplantation is the second leading cause of failure of keratoplasty. This article reviews the mechanism and treatment of secondary glaucoma after corneal transplantation.

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.

Topical Anesthesia Offers Sufficient Pain Control for MicroPulse Transscleral Laser Therapy for Glaucoma

Introduction

The aim of this study was to evaluate patient pain during and after MicroPulse Transscleral Laser Therapy (TLT) and vision-related quality of life using two different anesthesia protocols: “Topical Plus” anesthesia without standby anesthesia (study group), and analgosedation with standby anesthesia (control group).

Methods

A retrospective, comparative chart review was conducted to evaluate patient pain between the two groups based on an analog pain scale at baseline and postoperatively (1 hour, 6 hours, 1 day, 1 week, and 1 month). Furthermore, vision-related quality of life at baseline was compared at 1 month postoperatively.

Results

Four eyes underwent MicroPulse TLT under Topical Plus anesthesia and 4 eyes underwent analgosedation. The mean age at the time of the MicroPulse TLT was 78.3 ± 6.4 years. In the study group, the reported pain level increased significantly immediately after the treatment (from 0.5 to 2.8, p=0.003; mild pain); however, no difference was found at any later time point compared to baseline. The vision-related quality of life was similar in both groups and was not negatively impacted by the MicroPulse TLT at 1 month after the treatment. Discussion/Conclusion. The Topical Plus anesthesia protocol provides adequate pain control for the patient to remain comfortable during and post-MicroPulse TLT treatment, with no changes in vision-related quality of life. Although the sample size was small and, thus, the results cannot be generalized, this case series showed that it is possible to perform MicroPulse TLT under topical anesthesia.

Micropulse Transscleral Cyclophotocoagulation for Glaucoma after Penetrating Keratoplasty

The main objective of the article was to assess the surgical outcome of micropulse transscleral cyclophotocoagulation in patients presenting with glaucoma after penetrating keratoplasty. We conducted a retrospective study that included 26 eyes of 26 patients who presented with glaucoma after penetrating keratoplasty, and who were treated using micropulse transscleral cyclophotocoagulation between January 2017 and December 2020. The surgeries were performed using the Iridex Cyclo G6 MicroPulse P3 Probe. The intraocular pressure, mean number of antiglaucoma medications, visual acuity, corneal status, and postoperative complications were analyzed. The minimum follow-up period was 12 months. The success rate after 12 months was 76.9%. The baseline median intraocular pressure was 29 mm Hg and decreased to 18 mm Hg after 12 months. The median number of antiglaucoma medications was also reduced from three preoperatively to one after one year. In seven cases (29.92%), the visual acuity decreased and, in four cases (15.38%), the corneal graft was not transparent. We concluded that micropulse transscleral cyclophotocoagulation is an effective and safe method for the treatment of glaucoma after penetrating keratoplasty.

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

PURPOSE

Continuous-wave cyclophotocoagulation (CW-CPC) is often preferred to medical and surgical treatments for managing refractory glaucoma. This review summarizes diode CW-CPC indications, history, histopathology, methods, efficacy and safety. It also provides an overview of the latest data available on micropulse transscleral laser treatment (MP-TLT) that uses repetitive micropulses of diode laser energy in an off-and-on cyclical fashion.

METHODS

A literature review was conducted on transscleral CW-CPC (CW-TSCPC), endoscopic CPC (ECP) and MP-TLT. Relevant series of adult and paediatric patients were included for assessing the procedures.

RESULTS

Regarding CW-TCPC, highly variable success rates are reported in the literature, depending on the definition of success, type of underlying glaucoma, energy settings, follow-up duration and retreatment rates. CW-CPC often needs to be repeated, especially in paediatric patients. CW-CPC exposes to risks of inflammation and chronic ocular hypotony or phthisis with irreversible visual loss. CW-TSCPC has mainly been used in very severe forms of glaucoma, in painful eyes with limited visual potential or after filtering surgery failure. Published data on ECP are more limited but overall good success rates have been reported. Through the direct visualization of the targeted ciliary body in anatomically abnormal eyes, ECP is the preferred surgical procedure in paediatric refractory glaucoma. Complication rates are relatively low after ECP; however, large studies with long-term follow-up are needed. ECP may be used in difficult, refractory cases, but it is often used earlier when combined with cataract surgery. Despite limited data on the exact mechanism of action of MP-TLT and a lack of standardization of laser settings, the first data from heterogeneous case series shows that it has a similar efficacy and a better safety profile compared to CW-TSCPC in the medium term.

CONCLUSION

Although they may lead to sight-threatening complications, both CW-TSCPC and ECP seem effective. ECP appears to be superior to CW-TSCPC in paediatric refractory glaucoma. Unlike ECP combined with cataract surgery, evidence supporting a wider use of CW-TSCPC and MP-TLT in earlier stages of neuropathy is lacking. While it now appears that the safety profile of MP-TLT is superior to that of CW-CPC, robust prospective comparative studies including homogeneous and well-defined cohorts of patients are still needed to confirm an at least comparable efficacy in the long term.