January 01, 2000
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Improvement in vision quality is attainable with the Visx CAP Method, surgeon says

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VIENNA, Austria — The CAP (contoured ablation pattern) Method (Visx Inc., Santa Clara, Calif.) effectively treats de fined corneal irregularities that have resulted from previous refractive surgery. According to presenter Sheldon Herzig, MD, who presented information here at the European Society of Cataract and Refractive Surgeons meeting, the CAP Method also can help patients with decentered ablations, to treat the areas that should have been treated initially.

“We are dealing with situations where patients have lost best corrected visual acuity [BCVA],” Dr. Herzig told Ocular Surgery News. “The issue of refractive error is less significant. What we are trying to do is smooth out the corneal irregularities.” Dr. Herzig has used the CAP Method on patients with corneal transplants and irregular astigmatism from other refractive procedures.

Easy procedure; precise calculations

illustration---The CAP Method used with the Star S2 Excimer Laser System involves the isolation of part of the laser beam. The spot size of the laser can be manipulated to the desired size, with the treatment size ranging from 1.2 mm to 6.5 mm.

“You’ve got to do everything right,” Dr. Herzig said. “It is very important to be precise.” Luckily there are not too many of these types of patients, according to Dr. Herzig, who has done about 10 of these treatments. Care has to be taken since the beam from the Star S2 is being directed to a particular spot on the cornea. The laser is being surgeon controlled rather than topography map controlled. According to Dr. Herzig, since the treatment works on an x, y cartesian coordinate system, it presents the potential for a calculation error.

The CAP Method used with the Star S2 Excimer Laser System involves the isolation of part of the laser beam. The spot size of the laser can be manipulated to the desired size, with the treatment size ranging from 1.2 mm to 6.5 mm. Additionally, the laser spot can be elliptical, cylindrical or spherical. The beam is offset based on the coordinates indicated by the topographical map.

According to Dr. Herzig, the procedure is relatively easy but it takes some work to determine how to approach the patient. “Surgeons are going to spend considerable time studying the maps to determine the appropriate treatment coordinates,” Dr. Herzig said.

Course of action

The procedure can be done as photorefractive keratectomy or laser in situ keratomileusis, Dr. Herzig said.

“My goal has been to improve the patient’s BCVA,” Dr. Herzig said. “I wasn’t that concerned about their uncorrected vision because at this point in time, I didn’t know what effect treating these corneal irregularities would have on the patient’s refractive error. I preferred to first treat the irregular astigmatism and then go back and treat the residual refractive error.”

In Dr. Herzig’s study, the results demonstrated that selective corneal tissue removal using the CAP Method can help normalize corneal curvature and improve both visual acuity and vision quality.

Thus far, Dr. Herzig said he has en countered no complications from this procedure.

Use of the CAP Method is investigational in the United States.

For Your Information:
  • Sheldon Herzig, MD, can be reached at 1333 Sheppard Ave. E, Ste. 223, Willowdale, Ontario, M2J 1V1, Canada; (416) 494-7307; fax: (416) 494-4833. Dr. Herzig has no direct financial interest in the products mentioned in this article. He is a paid consultant for Visx Inc.
  • For more information on the CAP Method for the Star S2 excimer laser, contact Visx Inc., 3400 Central Ex press way, Santa Clara, CA 95051-0703; (800) 246-8479; fax: (408) 773-7055.