Innovation Spotlight - Catarex

Catarex

Catarex: The Next Best Hope For Cataract Surgery?

The current gold standard in removing cataracts today is phacoemulsification. According to a recent Snapshot Survey in Eyeworld magazine, cataract and refractive surgeons said they use phacoemulsification in 80 percent of their cases. With this technique, the surgeon makes a small incision of three millimeters and uses a probe that vibrates at ultrasonic frequency and emulsifies the lens nucleus. At the same time, the vibrating titanium tip of the probe softens the hard nucleus of the crystalline lens, so it may be aspirated from the eye.

Phacoemulsification requires a high level of skill by the surgeon, so researchers today are looking for better ways to remove a cataract. Optex Ophthalmologics thinks it has the solution. It has an innovative technology in the works that requires less time, less cost, and less skill than phaco. The company hopes, if proven, its technology will overtake phaco as the gold standard for cataract removal. Bausch & Lomb (B&L) of Rochester, N.Y., hopes so too. B&L has licensed the technology for human use, putting financial strength and marketing muscle behind the new technique, called Catarex. It was introduced to the scientific community at the Academy of Ophthalmology Meeting last fall.

Catarex is based on rotary impeller technology where the old cataract is removed through a 1 - 2 mm-capsular rhexis using a device, which is placed in a relatively stationary position inside the lens capsule. The impeller in the probe rotates at up to 100,000 rpms, creating a vortex that draws the cataract lens into contact with the impeller and emulsifies it. An integrated irrigation and aspiration removes the emulsified material. The procedure takes less than 10 minutes and uses a mechanical energy source rather than a laser or ultrasound to emulsify the cataract. Therefore, there is no possibility of stray radiation damaging the eye tissues and less heat is emitted. Catarex also has the potential to allow the lens capsule to remain functionally intact after surgery.

Catarex was created by bio-engineer Soheila Mirhashemi, Ph.D., physicist Dr. Michael Mittelstein, and chemical engineer Dr. John Sorensen. Together they created a company just to develop this technology.

Mirhashemi was quoted in Eyeworld magazine regarding the procedure: "We started by looking at the various technologies in the field of ophthalmology and learned about phaco," Mirhashemi explained. "We then evaluated the parameters necessary to remove the cataract lens from the eye."

Mirhashemi says they identified the three challenges associated with ultra-sound - the heat it may generate, endothelium exposure to stray energy, and the skill it requires. They conceived, developed and tested several prototypes. They then called the American Society of Cataract and Refractive Surgeons (ASCRS) to get a list of prominent ophthalmologists, finally selecting Dr. Richard P. Kratz, M.D., a clinical professor at the University of California, Irvine, as medical advisor. In addition, he will assess the technology.

Optex gained the financial backing of Venture Capital Company Atlantic Pharmaceuticals of Raleigh, N.C., and last year, it gained Bausch & Lomb as a "partner" when the company licensed the technology for human use.

Dr. Kratz presented the technology at last year's American Society of Cataract and Refractive Surgeons meeting in Seattle. In a film comparing Phaco with Catarex in a heat chamber, Kratz demonstrated that in 1 minute, Catarex had a temperature rise of about a degree while phaco had a rise of 10º F. And if something had occluded during the procedure, the Catarex rose about 2 ºF while phaco rose above 150º, which could result in corneal burns.

Samuel Masket, M.D., of West Hills, Calif., clinical professor of ophthalmology at Jules Stein Eye Institute, and Chairman of the ASCRS Cataract Surgery Special Interest Group, said Catarex has hopeful potential in theory.

"What makes this procedure so interesting is that it will potentially be able to remove the cataract through a smaller incision, and it may provide retention of a clear capsular bag. The latter will be a true innovation because it will be helpful toward development of an accommodating lens implant," he said.

Another benefit that Masket pointed out is that the machine has an automated lens capsular cutter that makes a reproducible small opening. Therefore, the skill needed by the surgeon is less than that required with current surgical methods. "Theoretically, this could work in 100 percent of cases," he said.

At the same time, Masket sees some serious concerns. "What is not clear at this time is whether Catarex will work for all levels of cataract formation and what the complications will be. This type of surgery can be problematic if there is a high incidence of capsular rupture. As a group, eye surgeons experience a 3 percent incidence of capsule rupture during phaco and that results in vitreous loss for 1 - 2 percent of the cases and the loss of lens material into vitreous in about 1 percent. In the case of a capsular rupture with this machine, lens material can be dispersed throughout the eye. We have to wait till we see how the device fares in clinical trials. If there is a significant percentage of capsular rupture, that would be a problem for the new technology."

Richard Kratz has spent 4 years working with Catarex, performing the procedure on live animals and a number of human lenses that were removed and embedded in a gelatin. He said there is a low potential for capsular rupture because the vacuum is low in contrast to phaco.

In an experiment to see the effect of a ruptured posterior capsule, Kratz deliberately created a central posterior capsule tear at the start of the procedure. After the nucleus and cortex were completely removed by Catarex, he could not find any nuclear particles in the vitreous and the vitreous face was still intact. "I believe that this was accomplished because of the low infusion and low vacuum that are used in Catarex," Kratz said. "I anticipate a low incidence of capsular rupture. Of course, this has to be proven in clinical trials."