Waterjet Hydrokeratome Patent Granted.

IRVINE, Calif.--(BW HealthWire)--Oct. 23, 1997--The U.S. Patent office has granted a patent for a "Hydrojet Apparatus for Refractive Surgery" to Visijet Inc. of Irvine.

United States Patent Number 5,643,299 describes a device that generates a 35 micron diameter focused waterjet beam and an eye fixation assembly positioned on the cornea.

The Visijet Hydrokeratome uses a high-energy, supersonic waterjet beam 35 microns in diameter to cut the cornea, specifically developed to create a LASIK flap. In receiving the patent, Visijet's President and Chief Operating Officer Jay Standish said: "We are very pleased that the patent office recognized the originality of our design and accepted all of Visijet's 20 claims describing the device. This patent strengthens Visijet's proprietary position in the use of waterjets in refractive surgery and adds significant value to our organization."

Leading the clinical program for the Visijet Hydrokeratome is Richard Lindstrom., M.D., of Minneapolis, who is Visijet's medical director. Lindstrom has worked closely with Visijet engineers to develop the first generation model which has demonstrated the ability to create lamellar flaps on animal and cadaver eyes at the Phillips Eye Institute.

According to Lindstrom: "The key to the Hydrokeratome's success is the extreme high pressure (over 15,000 psi) combined with the tightly collimated waterjet beam. Under these `ultra-fluidic' conditions, the water molecules leave the orifice of the instrument in excess of 800 mph and take on almost metallic properties."

In analyzing the results of pre-clinical testing, Lindstrom added that: "When we compared SEMs taken by the Phillips Eye Institute of corneas cut by the Hydrokeratome and those cut by a conventional metal blade microkeratome, we can see that the Hydrokeratome has the unique ability to cut between the layers of the lamellae, rather than across them as a microkeratome does. It is this so-called `interlamellar' action that results in cuts of such smoothness and precision."

The new patented design of the Hydrokeratome utilizes a first stage compressor to build an initial fluid pressure, which is then significantly increased by a second stage intensifier. The device consists of a base console unit which contains components to achieve the fluid pressure and controls for variable flap diameter and thickness, as well as a fixation device which is positioned on the cornea. Most of the patent claims concern the fixation device which includes a suction ring, pressure loss detection system, and electronic variable scan drive which allows for the waterjet beam to cut the flap in about 1.5 seconds with full visualization of the cornea.

While developmental issues still remain to be resolved, Standish says that the company is planning on a first generation clinical model to be available in early 1998.

Instrumental in this stage of development is Marguerite McDonald, M.D., of New Orleans. McDonald will be writing the Hydrokeratome clinical protocol, as well as serving as one of the first clinical investigators. As the first ophthalmologist to perform excimer laser refractive surgery on blind, as well as sighted eyes, and a recognized pioneer in refractive techniques, McDonald brings additional knowledge and valuable experience to the Visijet team.

According to McDonald: "The availability of this new waterjet technology may offer significant advantages to improving the weakest link in the LASIK procedure, the creation of the lamellar flap. The Hydrokeratome may be the solution we have been seeking."

In summarizing the potential benefits of waterjet technology, Lindstrom added that: "The Hydrokeratome offers the advantage of virtually metallic cutting action, but is always infinitely sharp. In addition, the interlamellar cut seems to eliminate the abrasive, planar cut of metal blades with the resulting rough surfaces, debris remnants and chatter marks. The waterjet seems to offer speed and a measure of automation beyond current technology. We can expect to see continued new developments in this fascinating technology."

Privately held Visijet, based in Irvine, is the ophthalmic division of Surgijet Inc., also of Irvine. The Visijet Hydrokeratome utilizes a high-speed, supersonic jet of water, only 35 microns in diameter, to make a corneal incision such as a LASIK flap, more cleanly and precisely than conventional metal blade microkeratomes.

Surgijet is developing waterjet instruments for a wide range of surgical applications including dentistry, orthopedics and cardiovascular, in addition to the Visijet ophthalmic instrumentation. The company is the holder of four issued patents on the use of waterjets in surgical applications with seven additional patents pending.

CONTACT: Visijet Inc., Irvine

Jay Standish, 714/450-1660, ext. 21