Treatment of glaucoma with high intensity focused ultrasound

Abstract

Glaucoma is a common disease mainly due to an increase in pressure inside the eye, leading to a progressive destruction of the optic nerve, potentially to blindness. Intraocular pressure (IOP) is the result of a balance between production of liquid that fills the eye--aqueous humour--and its resorption. All treatments for glaucoma aim to reduce IOP and can therefore have two mechanisms of action: reducing aqueous humour production by the partial destruction or medical inhibition of the ciliary body--the anatomical structure responsible for production of aqueous humour--or facilitating the evacuation of aqueous humour from the eye. Several physical methods can be used to destroy the ciliary body, e.g. laser, cryotherapy, microwave. All these methods have two major drawbacks: they are non-selective for the organ to be treated and they have an unpredictable dose–effect relationship. High intensity focused ultrasound (HIFU) can be used to coagulate the ciliary body and avoid these drawbacks. A commercially available device was marketed in the 1980s, but later abandoned, essentially for technical reasons. A smaller circular device using miniaturised transducers was recently developed and proposed for clinical practice. Experimental studies have shown selective coagulation necrosis of the treated ciliary body. The first three clinical trials in humans have shown that this device was well tolerated and allowed a significant, predictable and sustained reduction of IOP. The aim of this contribution is to present a summary of the work concerning the use of HIFU to treat glaucoma.

Comparison of Ultrasound Cycloplasty and Transscleral Cyclophotocoagulation for Refractory Glaucoma in Chinese Population

“…Cyclodestructive surgery with LASER energy such as TSCP is a well-established alternative to cyclocryotherapy. UCP is a method that uses high intensity focused ultrasound (HIFU) to transmit power to the target organ, in which the ultrasound energy is converted into a thermal effect to coagulate the target organ without affecting the adjacent tissues [9,10]. With the continuous improvement of the technology, UCP has come into the routine armamentarium of glaucoma surgeon.…”

Focused ultrasound in ophthalmology

“… 60 , 61 While the Sonocare system, which was the first FDA-approved HIFU device in any clinical specialty, 62 was ultimately commercially unsuccessful due to the contemporaneous introduction of laser surgery and improved medical therapy, HIFU techniques for glaucoma treatment continue to be investigated. 63 , 64 …”

Ultrasound Cyclo Plasty in Eyes with Glaucoma

“…Over the last years, a new device, named UCP, that employs high-intensity focused ultrasound (HIFU) has been developed, with the purpose of overcoming the limitations of traditional cyclodestructive techniques by achieving a more selective coagulation of the ciliary body and avoiding possible damages to the adjacent ocular structures 13,14,15,16,17,18,19,20,21 . In addition, the stimulation of supra-choroidal and trans-scleral portions of the uveo-scleral outflow pathway has been recently proposed as a possible adjunctive mechanism of the procedure in reducing IOP 22 .…”

“…In addition, the stimulation of supra-choroidal and trans-scleral portions of the uveo-scleral outflow pathway has been recently proposed as a possible adjunctive mechanism of the procedure in reducing IOP 22 . To date, seven major clinical studies have been conducted using the UCP device in different types and severity grades of glaucoma, demonstrating the effectiveness and the safety of this non-incisional procedure 14,15,19,20,21,22,23,24 .…”