SOLX Titaniam-Sapphire Laser for Treating Glaucoma: A First Report

On September 18th, Solx Inc., a Boston-based spinout from Boston University's Photonics Center, now based in Waltham, MA, announced that it had received FDA 510(k) clearance for its SOLX 790 Titanium:Sapphire laser to perform laser trabeculoplasty (TLT).

The clearance was based on the results of a multicenter, international clinical trial that established equivalency of TLT to argon laser trabeculoplasty (ALT) in its ability to reduce IOP in patients who have primary open-angle glaucoma and have poorly controlled IOP on maximally tolerated medications, and/or who have prior failed trabeculoplasty.

The laser was previously approved for sale in Europe and Canada.

In the trial, which was conducted across the United States, Europe, Canada and Israel, more than 180 patients were randomized either for ALT or TLT. Results showed that patients at 12-month follow-up achieved a mean IOP reduction of 6.8 ± 4.7 mmHg (25.8 percent) for TLT vs. 5.7 ± 4.8 mmHg (22.2 percent) for ALT.

"Patients treated with the SOLX 790 laser achieved an immediate reduction in IOP which was maintained at clinically beneficial levels throughout the study," said Francisco Fantes, M.D., Bascom Palmer Eye Institute, Miami, Florida, and Medical Monitor for the trial. "TLT does so without causing significant thermal damage to the treated tissues which provides glaucoma specialists with an important new tool for managing this disease."

"This is a significant milestone for SOLX," said Doug Adams, President and founder of SOLX, "The SOLX 790 laser is the cornerstone of our glaucoma management system along with the SOLX Gold Shunt."

The SOLX 790 laser emits pulses of energy at a near-infrared 790 nm wavelength to loosen particles in the trabecular meshwork without causing significant thermal damage. The energy penetrates deeper into the tissue than other currently used trabeculoplasty lasers and may therefore lead to longer-lasting treatment benefits

The SOLX 790 Laser is a flashlamp-excited, solid-state laser that emits near-infrared light in pulses lasting five to 10 microseconds. The laser has been shown to provide deeper tissue penetration, about 200 microns, deeper, than the other lasers currently used in trabeculoplasty without causing damage to the trabecular meshwork.

The following graphics and illustrations were taken from the SOLX, Inc., 790 Laser website:


The SOLX 790 Laser
Technical Specifications


Approvals and Ongoing Trials


How it Works Compared to the Argon (ALT) and Doubled YAG (green) (SLT) Lasers

A Comparison of the Technical Specifications for the Three Laser Systems



The Thermal Effects Differences Between the Three Lasers



IOP Following SOLX 790 Laser TLT Treatment


Average Number of Medications Needed Following SOLX 790 TLT Treatment


Glaucoma

Glaucoma is a disease of the eye in which damage is caused by elevated pressure within the eye. This elevated pressure is caused by a backup of fluid (aqueous humor) in the space/chamber between the cornea (the front surface of the eye), and the lens within the eye. Over time this pressure buildup causes damage to the optic nerve. Normal pressure in the eye varies between 10-20 mmHg.

There are several different types of glaucoma which are generally grouped in to two large categories: open-angle glaucoma and closed angle glaucoma.

Open-angle glaucoma: Glaucoma in which the aqueous (fluid) that flows through the cornea into the anterior (front) chamber of the eye cannot get through a filtration system called the trabecular meshwork into the drainage canals, causing pressure to build up within the eye which can damage the optic nerve and impair vision. Open-angle glaucoma is the most common form of glaucoma, and can be treated with the above types of lasers.

Closed angle glaucoma, (also called acute glaucoma or angle closure glaucoma), accounts for about 9 percent of all glaucoma cases and occurs when the opening between the cornea and iris narrows, such that the fluid cannot get to the trabecular meshwork and normal drainage channels. This narrowing results in fluid build-up and intraocular pressure. The fluid build-up happens very quickly.


I have previously written on the surgical and laser treatments for glaucoma. An overview can be found in my “Advances in the Treatment of Glaucoma”, done as an Optistock Industry Overview in the Fall of 2001. In addition, I have written extensively about another laser treatment for glaucoma, Selective Laser Trabeculoplasty (SLT) – SLT: New Treatment for Glaucoma Becomes Available , both in Ocular Surgery News (May 15, 2001) and an update on this laser methodology – An Update on the Use of SLT for Treating Glaucoma – in this Journal.