EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
Issue link: https://digital.eyeworld.org/i/407647
EW INTERNATIONAL 54 November 2014 by Matt Young and Gloria D. Gamat EyeWorld Contributing Writers Small industry players bring in glaucoma innovations with big potential A s the gold standard in traditional glaucoma surgery, trabeculectomy is a procedure that does not come without limitations; among them are chronic hypotony, choroidal effusion, and bleb leaks. Such limitations can lead to the need for repeat surgery over time and/or the need for other treatment options as well. In recent years, IOP-lowering innovations in glaucoma surgery have become available to address these issues. At the 2014 International Con- gress in Glaucoma Surgery (ICGS) held in Singapore, various glaucoma innovations were demonstrated, in- cluding a new shunt biomaterial to minimize the foreign body reaction, an intraocularly adjustable shunt that minimizes the risk of hypotony, a high intensity focused ultrasound, and a highly crosslinked hyaluronic acid for glaucoma treatment, among others. Instead of the usual company suspects, the innovators were small- er companies with special niches. These small companies may differ in the approach, but the endpoint is the same: better management of the flow of aqueous humor and lowering of IOP. The wonders of biostable shunt material The InnFocus MicroShunt (InnFocus, Miami) provides a quick and simple method of draining aqueous humor from the anterior chamber of the eye to a bleb using a flow restrictor made from a unique biomaterial called SIBS or poly (styrene-b-isobutylene-b-styrene) that leads to excellent IOP control without long-term vision-threaten- ing adverse events. About twice the size of an eyelash, this glaucoma shunt is a drainage implant consisting of a microtube. It has atraumatic fins that prevent migrations and peri- tubular leakage when inserted into the mouth of a needle tract formed under the limbus. The shunt matches the compliance of ocular tissue, conforms to the curvature of the eye, and is soft, flexible, and rubbery. However, the most important virtue of this material is the compo- sition: SIBS, an extremely biostable material with no chemical bonds that can cleave in the body and virtually no contaminants that can come out of the material and cause inflammation. Rabbit studies performed at the University of Miami, Bascom Palmer Eye Institute demonstrated that ophthalmic implants made from SIBS are significantly less irritating, less inflammatory, less capsule-form- ing, non-eroding, and non-occlud- ing as compared to similarly shaped silicone rubber controls. The InnFocus MicroShunt provides a quick and simple method of shunting aqueous humor from the anterior chamber to a diffuse bleb without the use of a scleral flap. "The purpose is to have something conceptually simple and easy to use that will guarantee a continuous result," said Guy Van de Weyer, director of operations EMEA, InnFocus. "It is a result that is sustainable with IOP in the range that everyone is looking for." SIBS was first used as the drug carrier in Boston Scientific's TAXUS drug-eluting coronary stent. It was the only polymer capable of keep- ing the 2–3 mm diameter vessels of the porcine coronary artery open without the presence of a drug. It has now been used in millions of patients for more than 12 years. "SIBS is the most biostable ther- moplastic elastomeric material in existence," Mr. Van de Weyer said. "If it worked in cardiology, why not in ophthalmology?" The power of ultrasound EyeTechCare's (Rillieux-la-Pape, France) solution to glaucoma sur- gery utilizes a high intensity focused ultrasound (HIFU) technology. "This kind of energy has been used for more than 20 years in many other indications, in particular can- cer treatment," said Fabrice Romano, DVM, founder of EyeTechCare. "This energy is extremely fascinating; it's able to coagulate tissue quite imme- diately even if deep inside the body, without making incisions." Dr. Romano is referring to how EyeOP1 works. Developed by EyeTechCare, this novel medical device is a system that initially was intended to deliver noninvasive treatment for refractory glaucoma. Today, it also is addressing the needs of less advanced glaucoma patients, in part due to excellent tolerance. The technology harnesses on focused ultrasound's ability to pass deeply through tissue without collateral damage. "When focused like the sun through the lens, at this point the energy is very high," Dr. Romano explained. "The technology is extremely effective in concentrat- ing at a small point. The higher the frequency, the more accurate the treatment. In our case, the target is less than 1 mm, and we use a very high frequency. We are able to place a small focal spot on the target." Ciliary bodies, responsible for producing aqueous humor behind the iris, are the typical targets of HIFU in EyeOP1. The treatment's primary objective is to coagulate 6 small parts of ciliary body to decrease the inflow to decrease IOP. "That's the first effect, and we thought it was the only one," Dr. Romano said. "With time we discov- ered the effect was a combination of two. There is an effect to reduce inflow. Another is on increasing out- flow. When we see the effectiveness, it's unusual." While trabeculectomy takes 30 minutes to 1 hour, treatment with EyeOP1 takes 2 minutes, and can be done in an outpatient basis under local anesthesia. In some countries, patients may be admitted in the hospital because of regulation in anesthesia application. Despite that, the procedure promises noninvasive- ness, lightened cost, and less patient downtime. Help in hyaluronic acid HealaFlow (Aptissen, Geneva, Switzerland) has various applica- tions in glaucoma treatment: It can be used in combination with any surgical procedure, in association with any solid implant, and with or without antimetabolites. Composed of a highly crosslinked hyaluronic acid, HealaFlow is a viscous and hydrophilic component designed to optimize aqueous humor drainage and to help maintain low IOP levels. Applicable in both penetrating and non-penetrating surgery, HealaFlow works by reducing con- tact between the different layers of the eye during surgery and by keep- ing the bleb optimally operational. Commenting on the ophthal- mic world's interest in this product, Olivier Benoit, CEO of Aptissen, said: "The major interest is that Innovations in glaucoma International outlook These small companies may differ in the approach, but the endpoint is the same: better management of the flow of aqueous humor and lowering of IOP. I nnovation is commonly driven by small startup companies that develop an idea into a product. Without exception, along the way there are false starts and redesigns. The result is that the product evolves with experience and ultimately is improved. Presented here are the next generation of glaucoma devices that are under development. We owe a lot to the inventors who think of new ways to improve treatments. However, a good idea is not enough. It also takes commitment and hard work to succeed. Small companies are uniquely positioned to bring these ideas to reality. John A. Vukich, MD, international editor