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Clinical Trial for Ultrasound Circular Cyclo Coagulation for glaucoma
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Ultrasound circular cyclocoagulation is a noninvasive treatment for refractory glaucoma that is approved in Europe.
By Cheryl Guttman Krader; Reviewed by Shlomo Melamed, MD
Rillieux la Pape, France-Ultrasound circular cyclocoagulation (UC3) is a fast, simple, noninvasive treatment that safely and effectively lowers IOP in eyes with refractory glaucoma.
It involves the precise delivery of high-intensity focused ultrasound to the ciliary body and ciliary processes and is performed using a proprietary system (EyeOP1, EyeTechCare) that comprises a control module and a sterile, disposable treatment probe. The treatment probe features six miniaturized 21-MHz ultrasound transducers, a positioning cone, and a suction ring.
After the treatment probe is fixated in place, the procedure is initiated via foot pedal control. Without the need for any additional maneuvers, a series of precisely positioned and evenly distributed coagulative lesions are created in the ciliary body and ciliary processes. Lesioning of these tissues is presumed to lead to IOP reduction secondary to decreased aqueous humor production and increased outflow through a widened uveoscleral pathway.
Safety studies in animals, which included histological evaluations, confirm the specificity of the treatment as there were no adverse effects on the iris, crystalline lens, sclera, or conjunctiva.
Clinical experience
Data from hundreds of patients treated with UC3 for advanced refractory glaucoma show the procedure results in a ≥20% reduction in IOP in about 70% of eyes with primary open-angle glaucoma and that the benefit is maintained for at least 1 year.
Clinical experience also demonstrates that the treatment is well tolerated under local (retrobulbar or peribulbar) anesthesia and associated with minimal post-treatment morbidity and no serious complications.
Patients may develop some minor conjunctival irritation and mild anterior chamber inflammation, but post-treatment discomfort is minor at worst. There have been no cases of severe permanent hypotony or high IOP spikes after UC3.
“Transscleral cyclophotocoagulation with diode laser has been the cyclodestructive technique of reference for more than 15 years, and it has a very positive impact on patients suffering with refractory glaucoma,” said Fabrice Romano, DVM, chief executive officer, EyeTechCare, Rillieux la Pape, France. “However, laser energy delivery with transscleral cyclophotocoagulation has low selectivity for the ciliary body and processes, and so the procedure is associated with collateral tissue damage, post-treatment pain, chronic inflammation, and visual acuity loss. Due to its poor tolerability and complications, transscleral cyclophotocoagulation is generally reserved for a narrow population of patients.”
In contrast, UC3 is associated with excellent tolerability while producing significant IOP lowering in eyes with refractory glaucoma, Dr. Romano noted.
“In fact, many users believe that because of its effectiveness and favorable safety profile, UC3 can be used at an earlier stage in glaucoma care,” Dr. Romano, added. “Based on this positive feedback, EyeTechCare is now sponsoring clinical trials evaluating UC3 in surgically naïve patients whose IOP is uncontrolled on maximally tolerated medications.”
The UC3 treatment probe comes in three sizes that enable optimal fitting, positioning, and treatment regardless of ocular anatomy. After the positioning cone is properly centered, suction is activated, allowing the suction ring to grip the conjunctiva gently and hold the treatment probe in place without distorting the eye.
“Proper centration of the positioning cone on the eye is important for proper delivery of the ultrasound to its intended target, but it is easily verified by confirming the presence of a uniform peripheral ring of visible white sclera,” Dr. Romano said.
Surgeons select the treatment parameters (exposure time per shot) using the control module’s intuitive touchscreen display. The total treatment time is about 2 minutes per eye.
UC3 is approved in Europe and is being performed in 10 western European countries, including in France where glaucoma specialists at 10 centers are using it as a routine treatment for patients with refractory glaucoma.
It is being investigated in a prospective, interventional study at the Goldschleger Eye Institute, Sheba Medical Center, Tel Aviv University, Ramat Gan, Israel, that enrolled 20 patients with an IOP ≥30 mm Hg on maximally tolerated medication and who had failed at least one filtering surgery.
Mean pre-treatment IOP was 36.4 mm Hg and was reduced to 18.6 mm Hg at 1 week.
At 1 year of follow-up, four patients had been re-treated, mean IOP for the 20 eyes was 22.5 mm Hg, and the procedure was considered a success (>20% reduction in IOP) in 65% of eyes.
“Our center often treats glaucoma patients in whom other procedures have failed,” said Shlomo Melamed, MD, professor of ophthalmology, Tel Aviv University. “Our experience with UC3 indicates it is an effective and well-tolerated therapeutic modality for that population. However, we believe it has definite potential for earlier use in glaucoma care.”
Data from 1 year of follow-up are also available for 52 eyes with refractory glaucoma enrolled in a multicenter study in France. Eligible eyes had IOP >21 mm Hg after one or more filtering surgeries.
The study eyes were divided into two groups that varied by treatment exposure time (4 or 6 seconds per shot). IOP in the two groups averaged 30.3 and 29 mm Hg, respectively, at baseline and was reduced by an average of 10 mm Hg at 12 months in both groups, with success rates of 63% and 44%, respectively.
Shlomo Melamed, MD
Dr. Melamed receives research grants from Allergan, Ellex, EyeTechCare, IOPtima, and SOLX.
Fabrice Romano, DVM
Dr. Romano is chief executive officer, EyeTechCare, Rillieux la Pape, France.
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