Mechanism of intraocular pressure decrease after contact transscleral continuous-wave Nd:YAG laser cyclophotocoagulation

MicroPulse™ transscleral cyclophotocoagulation in the equine patient: A case series of four horses

OBJECTIVE

To describe the clinical application and outcome of MicroPulse™ transscleral cyclophotocoagulation (MP-TSCPC) treatment in horses with glaucoma.

ANIMALS STUDIED

Four client-owned horses with primary (n = 2) or secondary (n = 2) glaucoma.

METHODS

Horses were treated with MP-TSCPC under standing sedation with a minimum of 30 days of follow-up (range 30-1241 days). Affected eyes were treated with a 31.3% duty cycle and 3000 mW laser power for a total of 180 s. Data collected included signalment, pre- and post-procedure intraocular pressures (IOPs), laser settings, medications, complications, and repeat therapy.

RESULTS

Four horses (5 eyes) received at least one treatment with MP-TSCPC. Mean preoperative IOP was 44 mmHg (range 33-49 mmHg). The immediate mean postoperative IOP was 34 mmHg (4 eyes; range 19-55 mmHg). At 1 week, IOP was 38 mmHg (5 eyes; range 21-80 mmHg), at 2 weeks was 40 mmHg (3 eyes, range 17-80 mmHg), at 1 month was 35 mmHg (5 eyes; range 20-50 mmHg), at 3 months was 18 mmHg (2 eyes; range 14-21 mmHg), at 6 months was 35 mmHg (2 eyes; range 30-39 mmHg), and at >300 days was 24 mmHg (3 eyes; range 18-29 mmHg). Complications included corneal ulceration (n = 1 eye), uncontrolled IOP (n = 3 eyes), and need for repeat treatment (n = 2 eyes).

CONCLUSIONS

MP-TSCPC used with the above-described settings was unsuccessful in treating the majority of cases. Future studies should be targeted at primary glaucoma cases and with use of alternative laser settings.

Microcyclophotocoagulation in Glaucoma Treatment: A Medium-Term Follow-Up Study

BACKGROUND

This study aimed to assess the effectiveness and safety of transscleral microcyclophotocoagulation (µCPC) in patients with glaucoma for eighteen consecutive months.

METHODS

Sixty-one patients (64 eyes) with primary and secondary glaucoma were enrolled to undergo µCPC (diode laser FOX 810, A.R.C. Laser, Nuremberg, Germany). The primary outcome measures were intraocular pressure (IOP) reduction, success rates, glaucoma medication use, and visual acuity after µCPC. An IOP reduction of 20% compared to the baseline value without re-intervention was considered a successful treatment. Complete success was defined as cessation of antiglaucoma medications. Secondary outcome measures included intraoperative and postoperative complications. Measurements were performed preoperatively and at the first week, and 1, 3, 6, 12, and 18 months postoperatively.

RESULTS

The mean ± SD values of IOP preoperatively at 1 day, 1 week, 1, 3, 6, 12, and 18 months postoperatively were 25.1 ± 8.4 mmHg, 17.3 ± 4.5 mmHg (p < 0.001), 16.5 ± 6.1 mmHg (p < 0.001), 20.5 ± 8.3 mmHg (p < 0.001), 17.1 ± 6.2 mmHg (p < 0.001), 18.0 ± 7.1 mmHg (p < 0.001), 15.8 ± 3.2 mmHg (p < 0.001), and 17.0 ± 5.9 mmHg (p < 0.001), respectively. The mean IOP at the last follow-up was reduced by 32.5%. The decrease in the number of antiglaucoma medications was statistically significant at each follow-up visit compared to the baseline. The qualified success rate was 38.5%. Two patients at 18-month follow-up did not require the use of antiglaucoma medications-complete success rate-3.1%. During the follow-up period, twenty-five eyes (39.1%) that required retreatment due to nonachievement of the target IOP were considered as failures. Eleven patients (12 eyes-18.8%) were lost to follow-up. A total of 26 patients (27 eyes) were evaluated 18 months after µCPC. Hypotony was observed in one patient (1.6%) and uveitis in two patients (3.1%) after the procedure. There were no other significant intraoperative or postoperative complications observed.

CONCLUSIONS

The µCPC is well tolerated and safe for reducing IOP in glaucoma patients in medium-term follow-up; however, success is moderate. Randomized, larger studies are needed to confirm the obtained results.

[Cyclophotocoagulation - current applications and practical aspects]

Despite the advent of a large variety of minimally invasive glaucoma surgery (MIGS) techniques cyclophotocoagulation (CPC) remains a popular treatment option to lower intraocular pressure (IOP) in glaucoma patients. Guidelines for glaucoma treatment point to the rather unphysiological mode of action and, thus, recommend CPC mainly for refractory glaucoma and/or eyes with limited visual potential. The primary target of CPC is the pigmented secretory ciliary body epithelium resulting in a decreased production of aqueous humor. In addition, an increase of aqueous outflow may contribute to the IOP lowering. CPC is generally considered a low risk intervention. However, macular edema, prolonged intraocular inflammation, vision loss, hypotony, pain or phthisis occur at considerable rates. Over the past decades new promising modes of cyclophotocoagulation have evolved aiming at reducing the risk of adverse effects and improving the efficiency. This article provides an overview of the different currently available cyclophotocoagulation modes: Besides the classic transscleral continuous-wave cyclophotocoagulation it covers endoscopic cyclophotocoagulation, micropulse transscleral laser treatment and transscleral controlled cyclophotocoagulation. Various practical aspects of the treatment in light of the current literature are being discussed.

MicroPulse Transscleral Laser Therapy Dosimetry Utilizing the Revised P3 Delivery Device: A Randomized Controlled Trial

PURPOSE

To compare the long-term effectiveness and safety outcomes of 2 treatment dosages of the MicroPulse Transscleral Laser Therapy (MPTLT) procedure on intraocular pressure (IOP) control in patients with primary open-angle glaucoma.

DESIGN

Single-blinded randomized controlled trial.

SUBJECTS

A total of 19 patients with POAG without prior history of incisional glaucoma surgery.

METHODS

Subjects randomized into 2 treatment groups, 100-second (total energy 78.25 joules [J], fluence 109.2 J/cm²) or 120-second (total energy 93.9 J, fluence 131.0 J/cm²) total treatment duration, underwent the MPTLT procedure with the revised P3 delivery probe delivering 2.5 W energy, 31.3% duty cycle, applied in 3 sweeps per hemisphere, avoiding 3 and 9 o'clock. All subjects were followed at 1, 3, 6, 9, and 12 months to compare reduction in IOP and medication.

MAIN OUTCOME MEASURES

Absolute and percentage IOP reduction at 6 months.

RESULTS

The treatment groups were similar in age, sex, and stage of glaucoma at baseline (all P > 0.05). The 120-second group had significantly better baseline best-corrected visual acuity (BCVA) and a higher percentage of patients with prior MPTLT therapy (ranging from 4-19 months before study). Significantly greater IOP reduction was noted in the 120-second group compared with the 100-second group at 3 months, with mean IOP reduction of 7.3 ± 4.2 mmHg (vs. 0.9 ± 2.5 mmHg, P = 0.006) and percentage IOP reduction of 32.2% ± 18.3% (vs. 4.1% ± 13.7%, P = 0.007). The 120-second group continued to outperform at 6-month follow-up: mean IOP reduction of 9.0 ± 4.8 mmHg (vs. 0.8 ± 2.5 mmHg, P = 0.016) and percentage IOP reduction of 37.8% ± 19.8% (vs. 3.6% ± 13.3%, P = 0.021). At 12 months, 37.5% and 18.2% of the 100- and 120-second groups, respectively, required an additional IOP-lowering procedure (P = 0.35); however, Kaplan-Meier analysis of time to intervention was not significantly different (P = 0.38). There were no vision-threatening complications or changes in BCVA during the study period.

CONCLUSIONS

This study demonstrates a dose-response relationship with improved IOP control and excellent safety profile in patients treated with higher treatment total energy and fluence using the revised MPTLT probe.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Micropulse diode laser therapy in refractory glaucoma

Purpose

Description of safety and efficacy of micropulse Transscleral cyclophotocoagulation as a treatment option for refractory glaucoma.

Methods

This is a prospective study including 39 eyes of 31 patients followed for refractory glaucoma, who benefited from transscleral cyclophotocoagulation using a microplused laser. The main indication for the procedure was increased ocular pressure refractory to quadritherapy in various types of glaucoma. The patients were treated using iridex Cyclo G6 laser with a Micropulse P3 infrared probe with a wavelength of 810 ​nm. The parameters for the procedure were a duration of 90 ​s per hemisphere with a power of 2000 mW and an energy of 180 ​J. Both the upper and lower hemispheres were treated in the same procedure, sparing the 3 o'clock and 9 o'clock meridians, and all the patients benefited from a single treatment session. The following parameters were evaluated: ocular pain and overall tolerance; visual acuity; and the evolution of IOP postoperatively up to 9 months.

Results

The glaucoma subtypes treated are as follows: primary open-angle glaucoma (n ​= ​05), chronic angle-closure glaucoma (n ​= ​13), neovascular glaucoma (n ​= ​07), aphakic glaucoma (n ​= ​06), malignant glaucoma (n ​= ​04), post-traumatic angle recession (n ​= ​02), and inflammatory glaucoma (n ​= ​02). The mean pre-operative intraocular pressure was 42.3 ​± ​5.2 ​mmHg and the mean post-operative intraocular pressure at 9 months was 16.9 ​± ​1.9 ​mmHg. The reduction in IOP was 49.9%. The average number of intraocular pressure-lowering medications used prior to surgery was four, and the average number of medications used at the 9-month post-operative visit was 2.0 ​± ​1.2 (70.3% of patients were on dual therapy). The overall success rate was 60.5%.

Conclusions

Micropulse transscleral cyclophotocoagulation appears to be a safe and efficient treatment for refractory glaucoma. Its indications should therefore be broadened and proposed early in various situations.

Success rate in micropulse diode laser treatment with regard to lens status, refractive errors, and glaucoma subtypes

PURPOSE

To evaluate the efficacy of micropulse transscleral cyclophotocoagulation (MP-TSCPC) considering different characteristics: glaucoma subtypes and lens status.

METHODS

A retrospective case-series study was designed to evaluate intraocular pressure (IOP), and the number of IOP-lowering medications, used by glaucoma patients treated with MP-TSCPC between 2016 and 2019. Cases had a follow-up period of 12 months. Achieving an IOP reduction higher than 20%, or the decrease of at least one IOP-lowering medication, was considered a successful outcome. The same population was analyzed by classifying them in two groups as: glaucoma subtypes and lens status. The baseline spherical equivalent (SE) was also calculated for considering association with the achieved IOP.

RESULTS

A total of 86 eyes were included. In most cases, IOP and IOP-lowering medications were decreased with a statistically significant difference (p < 0.0001), and all of them had a successful outcome. The percentage of IOP drop oscillated between 25.9% (open-angle glaucoma sub-group) and 37.5% (pseudoexfoliative glaucoma sub-group), 12 months after surgery. The difference between the groups was not statistically significant (p 0.20 and 0.32 for glaucoma subtypes and lens status, respectively). The Pearson's coefficient obtained was low for the SE and IOP association, at the 12 -month postoperative mark (- 0.009; p < 0.001).

CONCLUSIONS

The MP-TSCPC treatment was successful in decreasing IOP and IOP-lowering medications, in different glaucoma subtypes. Differences between groups (glaucoma subtypes, phakic and pseudophakic eyes) were not statistically significant. No association was found between the SE and the IOP achieved value after MS-TSCPC treatment.

Real-world outcomes of micropulse cyclophotocoagulation in a Latin American population and analysis of the factors associated with the success rate

OBJECTIVE

To report the outcomes of micropulse cyclophotocoagulation in a Latin American population with refractory glaucoma in a "real-world" setting and to evaluate the factors associated with success after a one-year follow-up.

MATERIALS AND METHODS

Retrospective, multicenter study. The medical records of patients who underwent micropulse cyclophotocoagulation between September 2017 and October 2018 were reviewed. Treatment success was defined as an intraocular pressure of 5 to 21 mmHg or a 20% intraocular pressure reduction with or without additional glaucoma medical therapy.

RESULTS

Eighty-three eyes from 83 patients were included, with a mean follow-up of 10.1 ± 3.1 months. The intraocular pressure and number of glaucoma medications significantly decreased at all postoperative visits from a mean of 21.9 ± 7.6 mmHg on 3.8 medications to 13.1 ± 3.5 mmHg on 2.8 medications at the 12-month follow-up. The mean intraocular pressure decreased 40.1% from baseline at 12 months. The cumulative success rate was 54.5% (95% CI, 44-67%) at 12-month follow-up. We identified a higher baseline intraocular pressure as a significant independent predictor of treatment success (p = 0.03). Late complications included 1 eye with corneal edema, 1 eye with prolonged anterior chamber inflammation and cystoid macular edema and 9 eyes (11%) with visual loss of 2 Snellen lines or more.

CONCLUSIONS

Micropulse cyclophotocoagulation is an effective and safe treatment for Latin American patients and can provide intraocular pressure and medication reductions with a single treatment after a one-year follow-up. A high baseline intraocular pressure was the most significant predictor of treatment success.

The place of endoscopic laser cyclodestruction in the system of microinvasive glaucoma surgery

Glaucoma is one of the leading causes of irreversible blindness in the world. Reducing intraocular pressure is the only way to slow down the progression of glaucomatous optic neuropathy. Minimally invasive glaucoma surgery aims to provide a safer way of reduction of intraocular pressure than traditional methods, and at the same time it is capable to reduce dependence on antihypertensive therapy. Cyclodestructive high-precision method of reducing the production of aquоeus humor occupies a confident position among modern minimally invasive glaucoma surgery methods. The data obtained as a result of studying the literature confirm our idea on the endoscopic laser cyclodestruction method as a minimally invasive, safe, reliable antiglaucomatous component of the combined surgical treatment of cataract and glaucoma.

Potential Mechanisms of Intraocular Pressure Reduction by Micropulse Transscleral Cyclophotocoagulation in Rabbit Eyes

Purpose

To evaluate the histological changes associated with, and the potential mechanisms of, intraocular pressure (IOP) reduction by micropulse cyclophotocoagulation (MP-CPC) in rabbit eyes.

Methods

MP-CPC was performed on the right eyes of Dutch belted rabbits, whereas the left eyes served as controls. The laser power settings were 250, 500, 750, 1000, 1500, and 2000 mW, 10 seconds per sweep, 100 seconds in total. IOP, outflow facility, and uveoscleral outflow tract imaging, using a fluorescent tracer, were examined at one week after MP-CPC. Changes of morphology and protein expressions in the outflow tissues, conjunctiva, and sclera were also evaluated.

Results

Significant reductions in IOP after MP-CPC were observed at 500 to 1000 mW (P = 0.036 and P = 0.014, respectively). The pre-MP-CPC IOP was 11.35 ± 0.41 mm Hg. At one week after surgery, the respective IOP values in the eyes treated at 500 mW and 1000 mW were 9.45 ± 0.49 mm Hg and 7.4 ± 0.27 mm Hg, respectively. Severe ciliary body damage was observed at 1500 to 2000 mW. MMP1–3 and fibronectin expression levels in the outflow tract and ciliary body were upregulated after MP-CPC. The α-smooth muscle actin (α-SMA) was upregulated at higher power levels. MP-CPC significantly increased uveoscleral outflow, whereas the outflow facility did not change. The α-SMA, collagen, and fibronectin were significantly upregulated in the subconjunctiva and sclera.

Conclusions

Reactive fibrotic responses were observed in the outflow tract, conjunctiva, and sclera after MP-CPC. A potential mechanism of IOP reduction by MP-CPC in pigmented rabbit eyes may involve increased uveoscleral outflow related to MMP upregulation.

Comparison of Aqueous Flare Values after Micropulse Transscleral Laser Treatment and Continuous Wave Transscleral Cyclophotocoagulation

PURPOSE

The purpose of this study was to analyse the changes in flare values after Micropulse Transscleral Laser Treatment for Glaucoma (MP-TLT) in patients with refractory glaucoma and to compare with the outcomes of patients who underwent continuous wave (CW) diode laser cyclophotocoagulation (CW-TSCPC).

METHODS

In this single-centre study, we reviewed the medical records of 54 patients who underwent MP-TLT and 35 patients who underwent CW-TSCPC at Ankara University Faculty of Medicine, Department of Ophthalmology. Aqueous flare values were measured by laser flare photometry.

RESULTS

The mean laser flare values in both groups (MP-TLT/CW-TSCPC) increased after surgery from 20.85 ± 8.74/22.14 ± 7.39 ph/ms at baseline to 48.52 ± 18.23/57.38 ± 20.08 ph/ms (P = .001) on day 1 and then progressively decreased to 44.13 ± 18.32/52.24 ± 20.56 in week 1, 40.5 ± 18.5/48.24 ± 19.23 week 2 and 35.28 ± 17.09/41.11 ± 16.7 month 1 (all p < .05) and returned to similar levels to baseline at month 3 and month 6 (both p > .05). Patients who achieved treatment success had significantly higher flare values than patients who failed on post-operative day 1, week 1 and week 2 in both groups. The flare values were significantly lower in the MP-TLT group than the CW-TSCPC group on post-operative day 1, week 1, week 2 and month 1 (all p < .05). There were no cases of prolonged post-operative inflammation or serious complications in both groups.

CONCLUSION

Intraocular inflammation, quantified by aqueous flare, may be a contributing factor to the IOP lowering effect of transscleral diode laser cyclophotocoagulation in the early post-operative period.

[Technique for laser activation of scleral hydropermeability in the treatment of patients with refractory forms of glaucoma]

Laser cyclodestructive interventions are considered the method of choice in the treatment of refractory glaucoma. However, the traumatic nature of cyclocoagulation makes it necessary to search for more gentle methods of laser treatment. One of the possible directions is the development of laser transscleral technologies that mainly affect the uveoscleral outflow. This article presents a new technique for laser activation of scleral hydropermeability (LASH) using pulse-periodic erbium glass (Er-glass) fiber-optics laser with wave length of 1.56 μm. The article describes the parameters of laser emission and the technique of LASH, and presents the mechanism of reducing intraocular pressure associated with increased transcleral drainage of intraocular fluid by forming new pores in the sclera. The effectiveness and safety of LASH is supported by a detailed example from clinical practice. This technology has proven itself as a possible alternative to the conventional contact transcleral cyclocoagulation.

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

Glaucoma is the leading cause of irreversible blindness worldwide, with primary open angle glaucoma (POAG) accounting for the greatest number of total glaucoma cases. This study aimed to evaluate the efficacy and safety of micropulse transscleral cyclophotocoagulation (MP-TSCPC) as a primary procedure in POAG during the COVID-19 pandemic. We retrospectively analyzed 60 eyes of 52 patients, who were diagnosed with mild-to-end-stage POAG without previous glaucoma surgery and received MP-TSCPC between 1 January 2020 and 31 August 2020. The mean preoperative intraocular pressure (IOP) significantly decreased from 27.8 mm Hg to 19.8, 20.1, 20.3, 20.4, and 20.2 mm Hg at 1, 3, 6, 9, and 12 months, respectively (all p < 0.05). The mean number of IOP-lowering medications used significantly decreased from 3.3 at the baseline to 1.6, 1.8, 1.8, 1.9, and 1.9 at 1, 3, 6, 9, and 12 months, respectively (all p < 0.001). Total withdrawal of antiglaucoma medications was fulfilled in five patients. The main outcome was achieved in 81.7% at postoperative month 12. The most common adverse effect was transient mydriasis (28.3%). No major complications were encountered. MP-TSCPC seems to be an effective and safe treatment to reduce IOP and the medication burden with minimal vision-threatening complications in mild-to-end-stage POAG patients without previous glaucoma surgery.

Micropulse transscleral cyclophotocoagulation in a Taiwanese population: 2-year clinical outcomes and prognostic factors

PURPOSE

To evaluate the 2-year efficacy and safety of micropulse transscleral cyclophotocoagulation (MP-TSCPC) in Taiwanese patients with glaucoma.

METHODS

We included the patients who received standardized MP-TSCPC with follow-up examinations on a regular basis for 24 months. Treatment success was defined as the attainment of a postoperative intraocular pressure (IOP) between 6 and 21 mmHg or a ≥ 20% reduction in IOP from baseline without an increase in glaucoma medications.

RESULTS

A total of 60 eyes from 56 patients who underwent MP-TSCPC for refractory glaucoma were included. The median age at MP-TSCPC intervention was 58.9 ± 12.4 years. The percentage of treatment success was 88.3% at 3 months, 83.3% at 6 months, 78.3% at 12 months, and 75.0% at 24 months. The mean baseline IOP prior to MP-TSCPC was 34 ± 11.9 mmHg (range 14-56 mmHg). The mean postoperative IOP decreased to 20.9 ± 10.0 mmHg, 18.0 ± 7.8 mmHg, 17.5 ± 6.4 mmHg, and 18.2 ± 7.1 mmHg after 3 months, 6 months, 12 months, and 24 months, respectively, in successful cases. The mean number of glaucoma medications at baseline was 3.8 ± 0.2, and the mean numbers of glaucoma medications at postoperative months 3, 6, 12, and 24 were 2.6 ± 0.7, 2.8 ± 0.6, 2.5 ± 1.4 and 2.6 ± 1.4, respectively, in successful cases. Younger age and prior CW-TSCPC significantly contributed to surgical failure in the multivariate model. Complications after MP-TSCPC included mild anterior chamber inflammation, conjunctival hemorrhage, hypotony, and mydriasis, and all subsided after treatment. None of the eyes developed vitreous hemorrhage, cystoid macular edema, or phthisis bulbi in the late postoperative period.

CONCLUSIONS

This study demonstrated that younger age and prior CW-TSCPC were risk factors for MP-TSCPC failure within 2 years. MP-TSCPC might be safe and effective for refractory glaucoma patients with maximal antiglaucoma medications.

Transscleral cyclophotocoagulation with MicroPulse® laser versus cyclophotocoagulation with continuous diode laser in patients with open-angle glaucoma

PURPOSE

To present the efficacy and safety of surgical treatment of moderate to advanced stage of open-angle glaucoma using the surgical method of transscleral cyclophotocoagulation with MicroPulse® laser (Iridex, Silicon Valley, California, USA) and to compare these results with those of continuous transscleral cyclophotocoagulation with diode laser.

METHODS

In a prospective observational clinical study 22 patients (30 eyes) with moderate and advanced open-angle glaucoma underwent transscleral cyclophotocoagulation. 15 eyes were treated with transscleral cyclophotocoagulation with MicroPulse® laser with 2500 mW (group A) and 15 eyes with continuous diode laser 810 nm and power between 2000 and 2300 mW (group B). The follow-up period of the study was 12 months.

RESULTS

A reduction of the intraocular pressure > 30% was achieved in 53.3% of the group A and in 60% of the group B during the follow-up period of 12 months. A statistically significant decrease of the number of antiglaucoma agents was observed in group A. One eye (6.6%) of group A underwent additional antiglaucoma procedures to achieve target intraocular pressure. The corresponding percentage is 40% in group B. The postoperative inflammatory response was significantly more limited in group A compared to group B.

CONCLUSIONS

The transscleral cyclophotocoagulation with MicroPulse® diode laser with 2500 mW achieves a similar decrease of the intraocular pressure as cyclophotocoagulation with continuous diode laser for the first postoperative months, but more satisfactory reduction of the number of eye drops as well as more limited postoperative inflammatory response.

Effect of high-intensity focused ultrasound (HiFU) treatment on intraocular pressure and aqueous humour dynamics: 12 -months results

PURPOSE

High intensity focused ultrasound (HiFU) is a cyclodestructive therapy for controlling intraocular pressure (IOP) in glaucoma. The mechanism of action is thought to be through destruction of the ciliary epithelium as well as increased uveoscleral outflow. We reviewed the change in aqueous humour dynamics parameters including aqueous humour flow rate, tonographic outflow facility (TOF) and uveoscleral outflow at 12 months.

PATIENTS AND METHODS

This is a prospective observational study. Consecutive patients with open angle glaucoma (OAG) or ocular hypertension (OHT) requiring further IOP lowering were enroled in the study between August 2016 and January 2017. Patients were commenced on medication washout period prior to baseline and twelve months' visit.

RESULTS

Sixteen patients (OAG) in the treatment group underwent assessment at twelve months follow up. Mean age was 63.1 ± 11 years. Eleven patients were African/Caribbean and 5 were Caucasian. Nine patients were female and 7 were male. Mean post-washout IOP was reduced by 21% (28.3 ± 5.7 at baseline vs 22.4 ± 8.4 mmHg at 12 months, p = 0.04). Aqueous humour flow rate was reduced by 16% at twelve months (2.40 ± 0.6 at baseline vs 2.02 ± 0.6 µl/min at 12 months, p = 0.0493). There was no statistically significant change in the TOF (0.12 ± 0.09 at baseline vs 0.08 ± 0.05 µl/min/mmHg at 12 months, p = 0.08) or uveoscleral outflow (0.6 ± 1.3 at baseline vs 1.3 ± 0.85 µl/min at 12 months, p = 0.15).

CONCLUSION

In this study, we demonstrated that the observed IOP reduction was likely due to aqueous humour flow rate reduction. The TOF and uveoscleral outflow were not detectibly changed.

Micropulse Transscleral Cyclophotocoagulation

How to cite this article: Abdelmassih Y, Tomey K, Khoueir Z. Micropulse Transscleral Cyclophotocoagulation. J Curr Glaucoma Pract 2021;15(1):1–7.

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.

Long-term results (>1 year) in 19 dogs treated with MicroPulse transscleral diode cyclophotocoagulation for refractory glaucoma

OBJECTIVE

To report the long-term (>1 year) outcome of MicroPulse transscleral diode cyclophotocoagulation (MP-TSCP) in dogs.

ANIMALS STUDIED

Client owned dogs that underwent MP-TSCP at a veterinary referral center.

PROCEDURE

Retrospective study of 19 dogs treated with MP-TSCP. Dogs were evaluated at a median follow-up time of 30.5 months postoperatively. Reported outcomes were intraocular pressure (IOP), retention or loss of vision, number of medications, and additional procedures performed. Variables associated with time to treatment failure were evaluated.

RESULTS

Data from 19 dogs (24 eyes) was available. Median laser settings employed were 140 s and 2200 mW at 31.3% duty cycle. Long-term postoperative IOP was lower than preoperative IOP values (14 mmHg (IQR = 22 mmHg, range: 4-52 mmHg) versus 30 mmHg (IQR = 31 mmHg, range: 8-62 mmHg), respectively). Laser settings >2000 mW were associated with a significantly longer time to reported failure. MP-TSCP was the sole therapy performed in 16/24 eyes resulting in long-term IOP control in 13/24 eyes and retention of vision in 6 of the 14 sighted eyes. Repeat MP-TSCP was performed in 10/24 eyes. Eight of 24 eyes required additional procedures with long-term IOP control in 4/8 eyes.

CONCLUSIONS

MicroPulse transscleral diode cyclophotocoagulation can be an effective treatment for refractory glaucoma in select cases. Higher laser settings increased time to reported failure, whereas age, glaucoma type, and preoperative IOP did not affect survival. MP-TSCP as sole therapy or coupled with additional glaucoma procedures controlled the IOP in 70% of cases.

Micropulse trans-scleral laser therapy outcomes for uncontrolled glaucoma: a prospective 18-month study

OBJECTIVE

To evaluate the efficacy and safety of micropulse trans-scleral laser therapy (mTLT) in glaucomatous patients.

DESIGN

Prospective, interventional study in a university hospital setting.

PARTICIPANTS

Fifty-two eyes of 52 adult patients with uncontrolled glaucoma despite maximal tolerated medical treatment, and/or poor candidates for filtering surgery.

METHODS

Participants received a 360-degree mTLT diode laser treatment (2000mW, 31.33% duty cycle), with duration adjusted to iris pigmentation and glaucoma severity (160-320 seconds). They were followed for 18 months to assess intraocular pressure (IOP), number of medications, corrected distance visual acuity (CDVA), glaucoma progression based on Humphrey Sita 24-2 perimetry and Cirrus high-definition optical coherence tomography, and complications. The primary outcome measure was the absolute success at 18 months. Absolute success was defined as an IOP 6-21 mm Hg and at least 25% IOP reduction, with equal or less number of IOP medications. Qualified success allowed for an increased number of IOP medications. Failure was defined as an inability to meet the criteria for success or the need for incisional glaucoma surgery.

RESULTS

Treatment absolute success was 61.5% at 12 months and 59.6% at 18 months. Mean IOP was reduced by 35.6% at 18 months (23.6 ± 6.5 mm Hg at baseline; 15.2 ± 4.1 mm Hg at 18 months, p < 0.001). mTLT did not significantly reduce the number of topical glaucoma medications (p = 0.075); however, 15 eyes (29%) had systemic oral glaucoma treatment at baseline and 10 eyes (20%) at 18 months. Eight patients (15%) experienced vision loss of ≥2 lines after the procedure. Three patients (6%) regained their preoperative CDVA by 1 month, and 3 patients (6%) by 3 months, while 2 patients (4%) sustained persistent visual loss. No ocular complications were noted in 84.6%. Incisional surgery was required in 25% of eyes owing to inadequately controlled glaucoma despite mTLT.

CONCLUSIONS

mTLT is a good therapeutic option for moderate IOP reduction, while being safe and predictable. This improved safety profile makes mTLT a treatment to be considered earlier in the management of glaucoma.

Phaco-UCP; combined phacoemulsification and ultrasound ciliary plasty versus phacoemulsification alone for management of coexisting cataract and open angle glaucoma: a randomized clinical trial

Background

Various surgical techniques have been described, to be combined with cataract surgery in glaucoma patients, aiming for an additional reduction of intraocular pressure (IOP), hence minimizing the burden of anti-glaucoma medication (AGM). Ultrasound ciliary plasty (UCP) is a recent microinvasive glaucoma surgery (MIGS) recommended for primary and refractory glaucoma. This study was conducted to evaluate the safety and efficacy of a new technique; combined phacoemulsification and ultrasound ciliary plasty (Phaco-UCP) as a primary surgical treatment for coexisting cataract and open angle glaucoma.

Methods

A randomized clinical trial, including 61 eyes of 61 patients with visually significant cataract and open angle glaucoma, randomized to either Phaco-UCP (study group; 31 eyes) or phacoemulsification alone (Phaco-alone) (control group; 30 eyes). Primary outcomes included reduction in IOP and/or the number of AGM. Secondary outcomes included visual acuity improvement and complications. Qualified Success was defined as an IOP reduction ≥ 20% from baseline value, with an IOP 6–21 mmHg, with no additional AGM or glaucoma surgery. Failure was defined as either < 20% IOP reduction, despite AGM use, the need of glaucoma surgeries or serious complications.

Results

At 18 months postoperatively, Phaco-UCP group had a median IOP reduction of 7 mmHg (Q1, Q3 = 3, 10) compared to 2 mmHg (Q1, Q3 = 2, 3) in Phaco-alone group (P < 0.001). Phaco-UCP group had significantly higher success rate at all time points reaching 67.7% at the last follow-up versus 16.7% only in Phaco-alone group (P< 0.001). The median number of AGM significantly decreased from [3 (Q1, Q3 = 2, 4), 3 (Q1, Q3 = 2,3)] respectively, (P =0.3)] at baseline to [1 (Q1,Q3 = 1, 2), 2 (Q1,Q3 = 2, 2)] respectively, (P < 0.001)] at 18 months postoperatively. No serious intraoperative or postoperative complications were encountered in either group.

Conclusion

Phaco-UCP is a simple, safe and effective procedure for management of coexisting cataract and open angle glaucoma.

Trial registration

ClinicalTrials.gov identifier, NCT04430647; retrospectively registered. June 12, 2020.

[Micropulsed diode laser transscleral cyclophotocoagulation: An effective technique whose role remains to be defined]

Micropulse Transscleral Cyclophotocoagulation (MP-TSCP) is a recently developed cyclodestructive procedure less aggressive than conventional TSCP. In this study, we aimed to evaluate the safety and efficacy of MP-TSCP in a real-life setting.

MATERIAL AND METHODS

We retrospectively included all MP-TSCP cases performed in the Bicêtre Hospital Ophthalmology department between January 2017 and September 2019. Intraocular pressure (IOP) and hypotensive medications were recorded preoperatively, at month 1, 3, 6 and at the conclusion of follow-up, as well as postoperative adverse events. Success was defined as an IOP between 6 and 21mmHg with a decrease of at least one medication or an IOP reduction>20%.

RESULTS

Thirty eyes (28 patients) were included. Preoperative IOP was 27.2±10.6mmHg, with 3.5±0.6 hypotensive medications, the mean deviation on the Humphrey 24-2 visual field was -21.9±6.9dB, and 43% of eyes had a past history of filtering surgery. The mean follow-up was 13.5±8.1 months. Eleven patients (37%) had to be retreated with MP-TSCP during follow-up. At 3 and 6 months and at the conclusion of follow-up, the IOP was 18.3±7.3mmHg (-33%; P<0.0001), 22.5±11.8mmHg, (-17%; P=0.052), 22.7±12.0mmHg (-16,5%; P<0.050), respectively. The success rates were 57%, 50% et 53% at 3 months, 6 months and at the conclusion of follow-up, respectively. Severe adverse events included 3 cases of corneal ulcers and 2 cases of severe but transient ocular hypotony without visual impairment.

CONCLUSION

MP-TSCP is an effective procedure for severe and/or refractory glaucoma, but retreatments are required in more than one-third of cases. Further studies are warranted to define factors predictive of success and indications for retreatment.

[Transscleral laser therapy in the treatment of glaucoma]

Nowadays glaucoma is one of the leading causes of irreversible blindness worldwide. The main goal in preservation of vision in glaucoma patients is reducing intraocular pressure (IOP), which is considered the main controlled risk factor for progression of glaucomatous optic neuropathy. The article discusses the effectiveness and safety of various transscleral laser technologies in the treatment of glaucoma. Modern transscleral laser technologies that affect the uveoscleral drainage and scleral hydro-permeability are less traumatic and more gentle making them promising in the treatment of patients with early stages of glaucoma, and not only in terminal glaucoma with pain syndrome resistant to conventional treatment ("last resort surgery").

Deconstructing aqueous humor outflow - The last 50 years

Herein partially summarizes one scientist-clinician's wanderings through the jungles of primate aqueous humor outflow over the past ~45 years. Totally removing the iris has no effect on outflow facility or its response to pilocarpine, whereas disinserting the ciliary muscle (CM) from the scleral spur/trabecular meshwork (TM) completely abolishes pilocarpine's effect. Epinephrine increases facility in CM disinserted eyes. Cytochalasins and latrunculins increase outflow facility, subthreshold doses of cytochalasins and epinephrine given together increase facility, and phalloidin, which has no effect on facility, partially blocks the effect of both cytochalasins and epinephrine. H-7, ML7, Y27632 and nitric oxide - donating compounds all increase facility, consistent with a mechanosensitive TM/SC. Adenosine A1 agonists increase and angiotensin II decrease facility. OCT and optical imaging techniques now permit visualization and digital recording of the distal outflow pathways in real time. Prostaglandin (PG) F2α analogues increase the synthesis and release of matrix metalloproteinases by the CM cells, causing remodeling and thinning of the interbundle extracellular matrix (ECM), thereby increasing uveoscleral outflow and reducing IOP. Combination molecules (one molecule, two or more effects) and fixed combination products (two molecules in one bottle) simplify drug regimens for patients. Gene and stem cell therapies to enhance aqueous outflow have been successful in laboratory models and may fill an unmet need in terms of patient compliance, taking the patient out of the delivery system. Functional transfer of genes inhibiting the rho cascade or decoupling actin from myosin increase facility, while genes preferentially expressed in the glaucomatous TM decrease facility. In live NHP, reporter genes are expressed for 2+ years in the TM after a single intracameral injection, with no adverse reaction. However, except for one recent report, injection of facility-effective genes in monkey organ cultured anterior segments (MOCAS) have no effect in live NHP. While intracameral injection of an FIV. BOVPGFS-myc.GFP PGF synthase vector construct reproducibly induces an ~2 mmHg reduction in IOP, the effect is much less than that of topical PGF2⍺ analogue eyedrops, and dissipates after 5 months. The turnoff mechanism has yet to be defeated, although proteasome inhibition enhances reporter gene expression in MOCAS. Intracanalicular injection might minimize off-target effects that activate turn-off mechanisms. An AD-P21 vector injected sub-tenon is effective in 'right-timing' wound healing after trabeculectomy in live laser-induced glaucomatous monkeys. In human (H)OCAS, depletion of TM cells by saponification eliminates the aqueous flow response to pressure elevation, which can be restored by either cultured TM cells or by IPSC-derived TM cells. There were many other steps along the way, but much was accomplished, biologically and therapeutically over the past half century of research and development focused on one very small but complex ocular apparatus. I am deeply grateful for this award, named for a giant in our field that none of us can live up to.

The effect of various media and probe angles on the power output of the Cyclo G6 Glaucoma Laser System

To evaluate the effect of various media and Iridex MicroPulse P3 (MP3) probe angles on the power output from the Cyclo G6 Glaucoma Laser (G6) System. A laser power meter was used to measure the power output (milliwatts, mW) of the Cyclo G6 System. Each of the ten trials consisted of measurements in six different media: no substrate, balanced salt solution (BSS), artificial tears (AT), tetracaine eye drop, lubricating ointment, and lidocaine gel. The output of the MP3 probe was measured at an angle of 90° and 45°, submerged in the respective media. The output was also measured with the probe held at 90° but above the medium. The mean power outputs with the probe being held at 90° to the sensor with no substrate, BSS, AT, tetracaine eye drop, lubricating ointment, and lidocaine gel were 358 ± 16.8 mW, 612 ± 14.2 mW, 613 ± 13.3 mW, 612 ± 14.0 mW, 620 ± 9.9 mW, and 610 ± 12.2 mW, respectively. These values were statistically higher than noncontact and 45° probe angles for each medium. The values between any two media (excluding no substrate) at a 90° probe angle with full contact were not statistically significant. The highest output of the G6 System was obtained with a 90° probe angle, with full contact and any of the coupling media.

Histopathologic changes in cadaver eyes after MicroPulse and continuous wave transscleral cyclophotocoagulation

OBJECTIVE

The purpose of this study was to compare the acute histological effects of MicroPulse transscleral cyclophotocoagulation (MPCPC) using the MicroPulse P3 Device and continuous wave transscleral cyclophotocoagulation (CWCPC) on the ciliary body and adjacent structures in human cadaver eyes.

METHODS

Quadrants of 6 human cadaver eyes from 3 different donors were subjected to traditional CWCPC, slow burn CWCPC, MPCPC, or no treatment (internal control). Sutures were used to differentiate different treatment areas on each eye. Differential inking was applied after treatments to aid in microscopic correlation. All specimens were subject to standard histologic processing. Tissue sections were cut at 4 microns and stained with hematoxylin and eosin according to established protocols. Pathologic evaluation by light microscopy was confirmed by a senior pathologist blinded to treatment groups.

RESULTS

In all 6 eyes, tissues treated with traditional and low burn CWCPC showed variable coagulative tissue damage to the ciliary body compared with untreated tissues. Minimal histologic changes were identified within the ciliary processes, although variable pigment clumping and streaming were noted within the pigmented ciliary epithelium. In contrast to CWCPC, MPCPC-treated tissues showed only minimal coagulative tissue damage to the ciliary body. Variable pigment clumping and streaming, however, were also noted in the pigmented ciliary epithelium in MPCPC-treated tissues.

CONCLUSIONS

In human cadaver eyes, MPCPC treatment caused less tissue disruption to the ciliary body compared with traditional and low burn CWCPC treatments. MPCPC may be a less destructive and more selective method of cyclophotocoagulation when compared with traditional and low burn CWCPC.

Comparison of the diurnal efficacy and safety of cyclocryocoagulation and cyclophotocoagulation in patients with refractory glaucoma

PURPOSE

To compare the diurnal IOP-lowering efficacy and safety of cyclocryocoagulation (CCC) and cyclophotocoagulation (CPC) in patients with refractory glaucoma.

METHODS

Forty eyes of 40 Caucasian patients with advanced primary or secondary glaucoma with only tunnel vision left were included in this retrospective, comparative interventional case series. Twenty eyes treated with CCC were compared with 20 eyes treated with CPC. Primary endpoint was the reduction of 24 h mean diurnal intraocular pressure (IOP; mean of 6 measurements), peak IOP and diurnal IOP fluctuations 3 and 6 months post-treatment. Secondary outcomes were the occurrence of postoperative complications and the identification of factors influencing the postoperative IOP reduction.

RESULTS

In the CCC group (mean age 70.6 ± 13.4 years), mean diurnal IOP was significantly reduced from 20.0 ± 4.5 mmHg to 14.7 ± 2.5 (p < 0.001) at 3 months and 13.9 ± 3.34 mmHg at 6-month follow-up (p < 0.001). In the CPC group (mean age 74.9 ± 9.0 years), mean diurnal IOP significantly decreased from 18.2 ± 3.1 mmHg to 13.2 ± 2.2 (p < 0.001) at 3 months and 13.1 ± 2.6 mmHg (p < 0.001) at 6 months. At 6 months, 75% of the CCC and 63% of the CPC group had mean diurnal IOP reductions of 20% or more. The most frequent complication (25%) was a transient IOP increase during the first days after CCC. A higher preoperative mean diurnal IOP was recognized as the only factor influencing the postoperative IOP reduction after CCC and CPC.

CONCLUSIONS

Both cyclodestructive methods seem to be reasonably safe and effective in lowering 24 h mean diurnal IOP in the perspective of 6 months in patients with refractory glaucoma. The IOP-lowering effect after CCC was better but not statistically significantly different compared to CPC. A higher rate of complications was observed in the CCC group, however.

Outcomes of micropulse transscleral cyclophotocoagulation in primary open-angle glaucoma, pseudoexfoliation glaucoma, and secondary glaucoma

PURPOSE

The aim of this study is to compare the outcomes of micropulse transscleral cyclophotocoagulation between primary open-angle glaucoma, pseudoexfoliation glaucoma, and other types of secondary glaucoma.

METHODS

Outcomes of 96 consecutive patients with refractory, end-stage glaucoma treated with micropulse transscleral cyclophotocoagulation were retrospectively reviewed. Follow-up examinations were performed on a regular basis until 12 months postoperatively. Surgical successes were defined as maintaining intraocular pressure ⩽18 mmHg and ⩾20% reduction in intraocular pressure (criteria A), ⩽15 mmHg intraocular pressure and ⩾25% reduction in intraocular pressure (criteria B), and ⩽12 mmHg intraocular pressure and ⩾30% reduction in intraocular pressure from baseline (criteria C).

RESULTS

Ninety-six eyes of 96 patients (50 (52%) females, 46 (48%) males) were included. Among all eyes, 32 were primary open-angle glaucoma, 30 were pseudoexfoliation glaucoma, and 34 were other types of secondary glaucoma. The mean age was 59.37 ± 11.45 (range: 20-91) years. The mean follow-up period was 14.2 ± 3.9 (range: 12-16) months. At 12 months, the success rates of primary open-angle glaucoma, pseudoexfoliation glaucoma, and secondary glaucoma group were 68.75%, 66.6%, and 64.7% (p = 0.185) for criteria A; 56.25%, 53.3%, and 50% (p = 0.153) for criteria B; and 43.75%, 43.3%, and 38.2% (p = 0.146) for criteria C. Four patients (12.5%) in primary open-angle glaucoma group, 5 patients (16.6%) in pseudoexfoliation glaucoma group, and 14 (41.2%) patients in other secondary glaucoma group required reoperation during the follow-up (p < 0.05).

CONCLUSION

Micropulse transscleral cyclophotocoagulation is an equally effective method of lowering intraocular pressure in patients with primary open-angle glaucoma, pseudoexfoliation glaucoma, and other types of secondary glaucoma. The rate of reoperation was higher in refractory secondary glaucoma patients.

The Effectiveness and Safety of Micropulse Cyclophotocoagulation in the Treatment of Ocular Hypertension and Glaucoma

PURPOSE

To evaluate the effectiveness and safety of primary and adjunctive micropulse cyclophotocoagulation (MPCPC) in the treatment of ocular hypertension (OHT) and glaucoma.

DESIGN

Retrospective cohort study.

PARTICIPANTS

Ocular hypertension and all severities of glaucoma (including treatment-naïve and well-sighted eyes) and all types of glaucoma (including normal-tension glaucoma [NTG]).

METHODS

Consecutive eyes with glaucoma or OHT that underwent MPCPC (Iridex Cyclo G6 Glaucoma Laser System, Mountain View, CA) between 2016 and 2018 were identified.

MAIN OUTCOME MEASURES

Intraocular pressure (IOP), visual acuity, glaucoma medications, and ocular adverse events.

RESULTS

Three hundred ninety-nine MPCPC surgeries, on 342 eyes of 214 patients, were analyzed. Laser power ranged from 900 to 2800 mW. Main diagnoses in descending prevalence were primary open-angle glaucoma (55.9%), chronic angle-closure glaucoma (10.8%), neovascular glaucoma (9.0%), NTG (6.5%), and OHT (5.5%). Mean baseline IOP was 19.8±7.4 mmHg and IOP reduction was 22.7%, 20.2%, 20.7%, and 23.7% at postoperative months (POMs) 1, 3, 6, and 12 (P < 0.0001 for all time points). The end point of 20% or more mean IOP reduction from baseline was achieved by 67.8% of the study cohort at POM 12. Additional mean IOP reduction of 16.4% (P < 0.0001) was achieved with each re-treatment. Analysis based on IOP stratification demonstrated 30.5% mean IOP reduction at POM 12 when baseline IOP was more than 21 mmHg and 20.1% when it was 21 mmHg or less (71% of overall cohort; P < 0.0001). Analysis based on laser power stratification demonstrated mean IOP reduction of 31.5% at POM 12 with laser power of 2500 mW or more and 17.8% with laser power of less than 2500 mW (P < 0.02). Overall, the mean number of topical glaucoma medications was unchanged from baseline to POM 12. Greater baseline IOP and number of baseline topical glaucoma medications were significant predictors of effectiveness in the regression analysis. No patients demonstrated persistent inflammation or hypotony, phthisis bulbi, or sympathetic ophthalmia.

CONCLUSIONS

In patients with OHT or glaucoma, MPCPC demonstrated effectiveness and safety in IOP reduction sustained to 1 year. Baseline IOP of 21 mmHg or less subgroup demonstrated a more limited response. A dose-response relationship is suggested with respect to laser power and repeat treatments.

Transscleral cyclophotocoagulation and its histological effects on the conjunctiva

Micropulse transscleral cyclophotocoagulation (MP-TCP) is increasingly being used as an initial procedure prior to conjunctival filtration surgeries. However, it is uncertain whether MP-TCP may cause inflammation and scarring of the bulbar conjunctiva. Thus, we aimed to study the histological effects of MP-TCP (compared to controls and continuous wave [CW]-TCP) on the conjunctiva. Our study included 10 Dutch Belted Rabbits that underwent TCP in their right eyes (n = 5, MP-TCP; n = 5, CW-TCP), while their left eyes served as controls. The rabbits were euthanised at 4 weeks, and their dissected globes underwent histopathological and immunohistochemical examination. We observed greater conjunctival inflammation in MP-TCP or CW-TCP-treated eyes compared to controls, but not between each other. The majority of the lymphocytic infiltrates were CD4 T-cells. Increased conjunctival fibrosis was evident in MP-TCP or CW-TCP-treated eyes, to similar extents, compared to controls. However, the increased staining for myofibroblasts was not statistically significant in TCP-treated eyes. We concluded that MP-TCP causes significantly greater overall conjunctival inflammation and scarring compared to controls, similar to CW-TCP. As these are risk-factors for fibrosis and failure of the conjunctival bleb, further studies are required to explore the effect, if any, of post-TCP conjunctival changes on future bleb morphology and survival.

Early results of micropulse transscleral cyclophotocoagulation for the treatment of glaucoma

PURPOSE

To describe our clinical experience with the efficacy and safety of micropulse transscleral cyclophotocoagulation as a treatment for glaucoma.

METHODS

In this retrospective case series, we reviewed the charts of 95 consecutive patients with various glaucoma subtypes who underwent micropulse transscleral cyclophotocoagulation. Patients were offered micropulse transscleral cyclophotocoagulation if they had perimetric glaucoma refractory to intraocular pressure-lowering topical medications and who were poor candidates for traditional filtering surgery. Eligible patients were treated with the Micropulse P3 device (IQ 810 Laser Systems; Iridex, Mountain View, CA, USA) at 2.0-2.5 W for a duration of 90 s per hemisphere at a 31.3% duty cycle. If a retreatment was needed, the power was increased to up to 3.0 W with other parameters remaining the same. Patients were considered successfully treated if their intraocular pressure was lowered by at least 20% compared to their baseline. The main outcome measure was post-operative intraocular pressure; secondary outcome measures included the number of adverse events and complications that occurred with treatment.

RESULTS

The glaucoma subtypes treated included primary open-angle glaucoma (n = 51), exfoliation glaucoma (n = 24), chronic angle-closure glaucoma (n = 15), and congenital/juvenile glaucoma (n = 5). The mean pre-operative intraocular pressure was 25.1 ± 5.3 mm Hg and the mean post-operative intraocular pressure at 12 months was 17.5 ± 5.1 mm Hg (p = 0.004). The mean number of intraocular pressure-lowering medications used preoperatively was 3.0 ± 1.1; the mean number of medications used at the 12-month post-operative visit was 1.4 ± 1.0 (p = 0.03). Success with one treatment was achieved in 73 (76.8%) of patients. With multiple treatments, all patients had significant intraocular pressure-lowering compared to baseline. The maximum number of treatments received by any single patient was 5. There were no instances of prolonged intraocular inflammation or long-term hypotony.

CONCLUSION

Micropulse transscleral cyclophotocoagulation appears to be a safe and efficacious treatment for glaucoma. Given its improved safety profile compared to continuous-wave transscleral cyclophotocoagulation, it deserves consideration as a primary procedure.

Benefits of SubCyclo Laser Therapy Guided by High-frequency Ultrasound Biomicroscopy in Patients With Refractory Glaucoma

PURPOSE

The purpose of this study was to evaluate the efficacy and safety of subliminal cyclophotocoagulation using a 25% duty cycle diode laser (Supra 810, SubCyclo, Quantel Medical).

METHODS

This was a pilot study of patients who underwent a SubCyclo photocoagulation procedure with a 25% duty cycle, between April 2016 and April 2017 at the Glaucoma Institute of Saint Joseph Hospital of Paris. All patients presented with an evolving moderate to severe glaucoma that were resistant to previous surgical treatments or with a contraindication for filtration surgery. Laser settings were programmed as follows: power 2000 mW, "on" time 0.63 ms, "off" time 1.9 ms, and 25% duty cycle per 100 seconds to each eye.

RESULTS

A total of 44 eyes of 34 patients were treated with subliminal cyclophotocoagulation, with a mean follow-up time of 12 months. Surgical success was defined as IOP ranging 6 to 21 mm Hg or a 20% IOP reduction at the last 12 months follow-up visit. The mean age of patients was 63.83±16.2 years. The mean preoperative IOP was 32.8±11.8 mm Hg which then decreased postoperatively to 24.02±7.03 mm Hg after 1 day, 18.34±8.31 mm Hg after 1 week, 18.26±8.53 mm Hg after 1 month, 20.5±8.53 mm Hg after 3 months, 18.9±9.2 mm Hg after 6 months and 18.8±9.3 mm Hg after 12 months. Our preliminary study using Subcyclo transscleral cyclophotocoagulation with a 25% duty cycle showed a 37% IOP reduction from the baseline after 3 months with a single laser session and a 45% reduction at the last 12 months follow-up, after more than one laser session. The mean number of ocular antihypertensive medications used was 3.4±1.7 before treatment which decreased to 3.0±1.6 after treatment. No significant complications or anatomic modifications were found after subliminal cyclophotocoagulation.

CONCLUSIONS

Subliminal cyclophotocoagulation with a 25% duty cycle is a safe and effective procedure for reducing IOP in cases of refractory glaucoma and seems to be safer than conventional transscleral cyclophotocoagulation.

Cyclodestructive procedures for refractory glaucoma

BACKGROUND

Cyclodestructive procedures are often used in patients with refractory glaucoma who have failed to achieve lower intraocular pressure (IOP) from filtration procedures and maximal medical therapy. Destruction of the ciliary body helps to lower IOP by reducing aqueous humor formation. Of the many types of cyclodestructive procedures, laser cyclophotocoagulation (CPC) has become the most common surgical method for reducing aqueous inflow. Options for CPC are wide-ranging: they can be performed using a neodymium:yttrium-aluminum-garnet (Nd:YAG) or diode laser and laser energy can be delivered by either the contact or non-contact method. Another cyclodestructive procedure is endoscopic cyclophotocoagulation (ECP), which the ophthalmologist can use selectively to target the ciliary epithelium and ablate ciliary body tissue. There is debate regarding which cyclodestructive method is best and how they compare to other glaucoma surgeries.

OBJECTIVES

To assess the relative effectiveness and safety of cyclodestructive procedures compared with other procedures in people with refractory glaucoma of any type and to assess the relative effectiveness and safety of individual cyclodestructive procedures compared with each other.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2018, Issue 9); Ovid MEDLINE; Embase.com; PubMed; LILACS BIREME; ClinicalTrials.gov and the WHO ICTRP. The date of the search was 21 September 2018.

SELECTION CRITERIA

We included randomized controlled trials or quasi-randomized trials in which participants underwent a secondary procedure for refractory glaucoma. We included trials with any laser type, route of administration, and laser settings. The primary comparison was any cyclodestructive procedure versus another glaucoma treatment, and the secondary comparisons were individual cyclodestructive procedures versus another cyclodestructive procedure.

DATA COLLECTION AND ANALYSIS

Two review authors independently reviewed the titles and abstracts from the database searches, and after retrieving the full-text reports of those that were potentially relevant, classified the full-text articles as included or excluded. Two review authors independently extracted data from the included studies and assessed the risk of bias. Discrepancies were resolved by discussion or by consultation with a third review author when necessary.

MAIN RESULTS

We included five trials reporting data for 330 eyes (326 participants). One study to had a low risk of bias for most domains and the other studies had an overall unclear risk of bias. This review includes four different comparisons: 1) ECP versus Ahmed implant, 2) micropulse CPC versus continuous-wave CPC; 3) CPC with a diode versus Nd:YAG laser; and 4) CPC with an Nd:YAG laser emitting 8J versus 4J.No study reported data for our primary outcome, change from baseline in pain severity as reported by the participant or change in number of pain medications.For our primary comparison, we included one trial that compared ECP with the Ahmed implant. At 12-month follow-up, the mean difference (MD) in IOPs between groups was -1.14 mmHg (95% confidence interval (CI) -4.21 to 1.93; 58 participants; low-certainty evidence (LCE)). At 24 months postintervention, we found very LCE suggesting that visual acuity may be better among participants in the ECP group than in the Ahmed implant group (MD -0.24 logMAR, 95% CI -0.52 to 0.04; 54 participants), and the difference in the mean number of glaucoma medications used by participants in each group was unclear (MD -0.50, 95% CI -1.17 to 0.17; 54 participants; very LCE). Reported adverse events in the ECP group (34 participants) were one case each of hypotony, phthisis bulbi, retinal detachment, and choroidal detachment; in the Ahmed implant group (34 participants) there was one case of endophthalmitis, two cases of retinal detachment, and six cases of choroidal detachment.Three types of comparisons from four included studies provided data for our secondary comparisons. In the study that compared micropulse with continuous-wave CPC, median IOP was reported to be similar between the two groups at all time points. At 18 months postintervention, the median number of IOP-lowering medications was reduced from two to one in both groups. One participant in the micropulse and two in the continuous group exhibited worsened visual acuity. One case of prolonged inflammation was seen in the micropulse group (23 participants). Seven cases of prolonged inflammation, five cases of hypotony, and one case of phthisis bulbi were seen in the continuous group (23 participants).Two studies compared CPC using a semiconductor diode versus an Nd:YAG laser. At 12 months postintervention, the MD in IOP was 1.02 mmHg (95% CI -1.49 to 3.53) in one study (LCE). The second study did not report mean IOP beyond three months of follow-up. Neither study reported the mean change in best-corrected visual acuity or number of glaucoma medications. Both studies reported hypotony as an adverse event in three participants in each study.One study compared different energy settings of the same Nd:YAG laser. At 12-month follow-up, visual acuity was unchanged or improved in 21 of 33 participants in the 8J group and 20 of 27 participants in the 4J group (risk ratio 0.86, 95% CI 0.61 to 1.21; very LCE). More participants in the 8J group reduced the number of medications taken compared with the 4J group (RR 1.49, 95% CI 0.76 to 2.91; 50 participants; very low-certainty evidence). The presence of fibrin or hyphema were seen in five participants who received 8J and none who received 4J. There was a severe anterior chamber reaction in 11 of 26 (42%) participants who received 8J of energy and 2 of 21 (10%) participants who received 4J of energy.

AUTHORS' CONCLUSIONS

Evidence from five studies included in this review was inconclusive as to whether cyclodestructive procedures for refractory glaucoma result in better outcomes and fewer complications than other glaucoma treatments, and whether one type of cyclodestructive procedure is better than another. The most commonly reported adverse events across all five studies were hypotony and phthisis bulbi. Large, well-designed randomized controlled trials are needed. Patient-reported outcomes such as pain and quality of life should be considered as primary outcomes or important secondary outcomes of future trials.

Intraocular inflammation after Ultrasound Cyclo Plasty for the treatment of glaucoma

This is a prospective interventional clinical study evaluating intraocular inflammation developed after Ultrasound Cyclo Plasty (UCP) for the treatment of glaucoma. Eighteen eyes of 18 patients were treated with UCP second-generation probes (Eye OP1). After treatment, the mean intraocular pressure (IOP) significantly decreased from 26.8±7.2 to 18.8±6.1 mm Hg at day 1 and to 14.7±3.4 mm Hg at month 6 (all P<0.001). Mean laser flare-cell photometry value steeply increased after surgery from 12.1±7.5 to 64.1±53.9 ph/ms (P=0.001) at day 1, and then progressively decreased to respectively 60.6±49.7 at day 7, 43.5±38.5 at day 14 and 28.2±18.3 at month 1 (all P<0.05), returning at levels similar to baseline ones at month 3 and month 6 (respectively 16.7±6.2 and 12.8±10.2, both P>0.05). A significant negative correlation was found between postoperative increase of aqueous flare values and anterior chamber depth (R=-0.568, P=0.014). This timeframe may be considered reasonable for repeating UCP treatment, when required.

Micropulse Transscleral Cyclophotocoagulation: A Look at Long-Term Effectiveness and Outcomes

PURPOSE

To investigate the long-term effectiveness of intraocular pressure (IOP) and medication reduction in patients who have undergone micropulse transscleral cyclophotocoagulation (mTS-CPC).

DESIGN

Retrospective chart review.

PARTICIPANTS

A total of 73 eyes of 62 patients treated no more than 1 time with mTS-CPC in a practice in New York City with at least 1 year of follow-up.

METHODS

Treatment was 100 seconds of mTS-CPC with energy titrated on the basis of visual acuity. Paired t test and multivariable analysis were performed with SAS (SAS Institute Inc, Cary, NC).

MAIN OUTCOME MEASURES

Visual acuity, IOP, medication burden, phthisis, and development of macular edema were followed.

RESULTS

Average initial IOP was 25.5±9.4, and average number of initial medications was 3.1±1.1. At 1 year, average IOP was 13.8±7.0 (46% reduction) and average number of medications was 2.5±1.0 (19% reduction). A total of 11 of 15 patients (73.3%) initially taking an oral carbonic anhydrase inhibitor before CPC did not require the oral carbonic anhydrase inhibitor 1 year after treatment. Seventy-six percent of patients obtained at least 20% IOP reduction. Multivariate analysis found IOP reduction was associated with power used and preoperative IOP, whereas medication reduction was associated with initial medication burden. Notably, there was a 57% reduction in IOP at 2500 mW power and a 30% reduction at 2000 mW power. No patients developed macular edema or phthisis from the procedure. Some 18.8% of patients with 20/400 vision or better experienced persistent vision loss of ≥2 lines after the procedure, and 10% of patients with light perception to count finger vision progressed to no light perception (NLP) after the procedure. Of patients with 20/400 vision or better, 12.5% gained ≥2 lines of visual acuity on the Snellen chart at the postoperative year 1 visit. In addition, 15.4% of patients with count fingers to NLP vision improved at the postoperative year 1 visit after treatment. One of 6 patients (16.7%) with NLP gained vision at the postoperative year 1 visit.

CONCLUSIONS

This study provides evidence that mTS-CPC is a clinically useful procedure associated with good long-term medication burden reduction and IOP reduction that follows a dose-response pattern related to power used.

Cyclodestructive Procedures in Glaucoma: A Review of Current and Emerging Options

The first surgical modalities to reduce aqueous humor production by damaging the ciliary body date back to the early twentieth century. Until recently, however, cyclodestructive procedures (e.g., cyclocryotherapy and transscleral diode laser photocoagulation) have been reserved as last option procedures in refractory glaucoma patients with poor visual potential. Emerging technologic innovation has led to the development of promising, safer and less destructive techniques, such as micropulse diode cyclophotocoagulation, endoscopic cyclophotocoagulation and ultrasound cyclodestruction. Consequently, an emerging paradigm shift is under way with the selection of these surgical options in eyes with less severe glaucoma and good visual potential. Although existing evidence has not, as yet, adequately defined the role and value of these procedures, their emergence is a welcome expansion of available options for patients with moderate-to-severe glaucoma. This article reviews the pertinent evidence on both established and evolving cyclodestructive techniques and describes their growing role in the management of glaucoma.

Efficacy and Safety of Micropulse® Transscleral Cyclophotocoagulation in Glaucoma

OBJECTIVE

To report the results using Micropulse^® transscleral cyclophotocoagulation (Iridex) in the treatment of glaucoma.

METHODS

Retrospective study in adult patients with glaucoma with at least 6 months of follow-up, and only one session of Micropulse^®. The same surgical technique was used in all cases. The only laser parameter that could vary was the total treatment duration (in seconds). The remaining parameters were fixed at 2 Watts of power and 0.5ms (31.3%) of active cycle.

RESULTS

A total of 22 eyes of 17 patients with glaucoma of various types and stages were included (mainly congenital and pseudoexfoliation). The mean follow-up time was 7.9 months. The total treatment duration varied from 100 to 180seconds. Definition of success: 5mmHg <Intraocular pressure (IOP)<21mmHg and a reduction of ≥20% of the baseline value and no addition of oral carbonic anhydrase inhibitors, and no re-operation. The overall success rate was 72.7% in the first month, 54% at 4 months, 41% at 6 months, and 27.3% at final follow-up. Patients with longer treatment durations (180s) achieved better results. The mean reduction in IOP in successful eyes was 36% (from 26.3 to 16.7mmHg, SD 4.58, P=.028). No complications were reported.

CONCLUSIONS

In a heterogeneous population of glaucoma (mostly congenital and pseudoexfoliation types), a low success rate (27.3%) was obtained in the medium-term with a single session of Micropulse^®.

Cyclodestructive procedures for non-refractory glaucoma

BACKGROUND

Glaucoma is a leading cause of blindness worldwide. It results in a progressive loss of peripheral vision and, in late stages, loss of central vision leading to blindness. Early treatment of glaucoma aims to prevent or delay vision loss. Elevated intraocular pressure (IOP) is the main causal modifiable risk factor for glaucoma. Aqueous outflow obstruction is the main cause of IOP elevation, which can be mitigated either by increasing outflow or reducing aqueous humor production. Cyclodestructive procedures use various methods to target and destroy the ciliary body epithelium, the site of aqueous humor production, thereby lowering IOP. The most common approach is laser cyclophotocoagulation.

OBJECTIVES

To assess the effectiveness and safety of cyclodestructive procedures for the management of non-refractory glaucoma (i.e. glaucoma in an eye that has not undergone incisional glaucoma surgery). We also aimed to compare the effect of different routes of administration, laser delivery instruments, and parameters of cyclophotocoagulation with respect to IOP control, visual acuity, pain control, and adverse events.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2017, Issue 8); Ovid MEDLINE; Embase.com; LILACS; the metaRegister of Controlled Trials (mRCT) and ClinicalTrials.gov. The date of the search was 7 August 2017. We also searched the reference lists of reports from included studies.

SELECTION CRITERIA

We included randomized controlled trials of participants who had undergone cyclodestruction as a primary treatment for glaucoma. We included only head-to-head trials that had compared cyclophotocoagulation to other procedural interventions, or compared cyclophotocoagulation using different types of lasers, delivery methods, parameters, or a combination of these factors.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened search results, assessed risks of bias, extracted data, and graded the certainty of the evidence in accordance with Cochrane standards.

MAIN RESULTS

We included one trial (92 eyes of 92 participants) that evaluated the efficacy of diode transscleral cyclophotocoagulation (TSCPC) as primary surgical therapy. We identified no other eligible ongoing or completed trial. The included trial compared low-energy versus high-energy TSCPC in eyes with primary open-angle glaucoma. The trial was conducted in Ghana and had a mean follow-up period of 13.2 months post-treatment. In this trial, low-energy TSCPC was defined as 45.0 J delivered, high-energy as 65.5 J delivered; it is worth noting that other trials have defined high- and low-energy TSCPC differently. We assessed this trial to have had low risk of selection bias and reporting bias, unclear risk of performance bias, and high risk of detection bias and attrition bias. Trial authors excluded 13 participants with missing follow-up data; the analyses therefore included 40 (85%) of 47 participants in the low-energy group and 39 (87%) of 45 participants in the high-energy group.Control of IOP, defined as a decrease in IOP by 20% from baseline value, was achieved in 47% of eyes, at similar rates in the low-energy group and the high-energy groups; the small study size creates uncertainty about the significance of the difference, if any, between energy settings (risk ratio (RR) 1.03, 95% confidence interval (CI) 0.64 to 1.65; 79 participants; low-certainty evidence). The difference in effect between energy settings based on mean decrease in IOP, if any exists, also was uncertain (mean difference (MD) -0.50 mmHg, 95% CI -5.79 to 4.79; 79 participants; low-certainty evidence).Decreased vision was defined as the proportion of participants with a decrease of 2 or more lines on the Snellen chart or one or more categories of visual acuity when unable to read the eye chart. Twenty-three percent of eyes had a decrease in vision. The size of any difference between the low-energy group and the high-energy group was uncertain (RR 1.22, 95% CI 0.54 to 2.76; 79 participants; low-certainty evidence). Data were not available for mean visual acuity and proportion of participants with vision change defined as greater than 1 line on the Snellen chart.The difference in the mean number of glaucoma medications used after cyclophotocoagulation was similar when comparing treatment groups (MD 0.10, 95% CI -0.43 to 0.63; 79 participants; moderate-certainty evidence). Twenty percent of eyes were retreated; the estimated effect of energy settings on the need for retreatment was inconclusive (RR 0.76, 95% CI 0.31 to 1.84; 79 participants; low-certainty evidence). No data for visual field, cost effectiveness, or quality-of-life outcomes were reported by the trial investigators.Adverse events were reported for the total study population, rather than by treatment group. The trial authors stated that most participants reported mild to moderate pain after the procedure, and many had transient conjunctival burns (percentages not reported). Severe iritis occurred in two eyes and hyphema occurred in three eyes. No instances of hypotony or phthisis bulbi were reported. The only adverse outcome that was reported by the treatment group was atonic pupil (RR 0.89 in the low-energy group, 95% CI 0.47 to 1.68; 92 participants; low-certainty evidence).

AUTHORS' CONCLUSIONS

There is insufficient evidence to evaluate the relative effectiveness and safety of cyclodestructive procedures for the primary procedural management of non-refractory glaucoma. Results from the one included trial did not compare cyclophotocoagulation to other procedural interventions and yielded uncertainty about any difference in outcomes when comparing low-energy versus high-energy diode TSCPC. Overall, the effect of laser treatment on IOP control was modest and the number of eyes experiencing vision loss was limited. More research is needed specific to the management of non-refractory glaucoma.