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Surgeon: more proof needed to back LASEK
Lack of scientific evidence leads one surgeon to be skeptical of the new procedure.
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NEW YORK — Although laser epithelial keratomileusis is enjoying growing acceptance as an alternative to LASIK and photorefractive keratectomy, one physician said he cannot support use of the procedure without more scientific evidence of its efficacy and safety.
“Before I as a physician market, sell and consent a patient for LASEK over and above PRK, I need to be sufficiently convinced of what I’m saying. To convince me in this case will require a prospective, randomized, double-masked, controlled trial. The differences we observed between (LASEK and PRK) in our own study were extremely small and not statistically significant. Therefore it did not justify me selling LASEK as a new and improved procedure,” said Dan Z. Reinstein, MD, MA, FRCSC, assistant professor of clinical ophthalmology here at the Weill Medical College of Cornell University, and in private practice in London.
Dr. Reinstein said he is not opposed to the procedure, but he needs to see more scientific evidence before he elects to use it instead of standard PRK in his practice.
“I look forward to seeing good scientific evidence that would have me switch from PRK. I like LASEK. In terms of my feelings toward it, I enjoyed it. I’m pleased with the ballet under the microscope; it’s very elegant,” he said.
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Lack of randomization
Rather than cutting a stromal flap as in LASIK, in LASEK the epithelium is disengaged from the stroma as a sheet, lifted from the stromal surface on a hinge and then replaced after the laser ablation. Among the chief advantages claimed for the procedure are less pain, faster visual recovery and reduced or no haze when compared with PRK.
“With LASEK, as fancy and as interesting as it looks on the screen, I still have not seen any convincing evidence that compared to PRK it reduces pain, speeds up visual recovery and leads to less haze,” Dr. Reinstein said.
“Given that the differences between LASEK and PRK in terms of pain and visual recovery are small, it is not sufficient to make these claims based on consecutive uncontrolled series of LASEK treatments. With respect to haze, so far I have yet to see a randomized, prospective, masked trial showing that the haze is less from one procedure to the other. Large, uncontrolled series are not sufficient proof to make this claim.
“In fact, if you look at the data we had in our own prospective, randomized, double-masked, controlled trial performed with Emma Cremonesi, MD, from Mexico, which admittedly was limited to only 30 eyes of 15 patients, at 4 months there was a greater number of eyes with haze in the LASEK group than the PRK group. This might not be statistically significant, but my point is there have been many claims made and a lot of excitement about LASEK without the proper evidence to support them. Documented proof is needed before directing a mass stampede toward LASEK and away from a very different procedure called PRK,” he said.
Dr. Reinstein was referring to a study he conducted with Dr. Cremonesi, comparing recovery after standard PRK to LASEK. In 15 patients, one eye was randomized to undergo LASEK and the other to PRK. In postop evaluations, there were no statistically significant differences between the two groups in all visual and subjective measures of symptoms.
Dr. Reinstein noted that a study of 10,000 eyes randomized to PRK or LASEK would be needed to demonstrate that the small differences observed in his study were actually significant.
“Let’s remember less pain and faster visual recovery were the claims initially made about LASEK,” he said. “I would love nothing better than that. But no one has provided a randomized, controlled, prospective, masked study showing a difference.”
Possible dangers
According to Dr. Reinstein, quick endorsement of LASEK is dangerous for two reasons. First is the fear of creating buzz on something new that ultimately does not work, something he said has occurred many times before in refractive surgery.
“All along, people have been making claims that are unsubstantiated, all the lemmings jump off the cliff, and then subsequently we find out the reality. Look at hexagonal keratotomy, look at hyperopic automated lamellar keratoplasty,” he said.
“LASEK has been around now for some time, so it is probably as safe as PRK. But let us not forget that placing epithelial cells, destroyed by alcohol, back onto the cornea, could theoretically pose extra risks.
“Could the fact that we’re placing devitalized tissue back be a bad thing? If you’re putting dead cells onto the center of the cornea, who is to say that is not worse for the cornea than removing the cells and letting it heal over like a regular PRK? You’ve got dead cells that don’t come back to life, they have to be taken away by other processes. They have to be removed by the body.
“Now you’re giving the cornea two things to do. You’re having the epithelium from the periphery grow to resurface in the stroma in the center, but you’re also asking the body to clear a sheet of dead epithelial cells from the center. This is a lot more work than simply allowing it to grow over from the periphery. You’ve got dead organic material on a wound now. Could this theoretically increase the chances of an infection?” he asked.
For Your Information:
- Dan Z. Reinstein, MD, MA, FRCSC, can be reached at Reinstein Institute/Eye Academy of London, 114A Harley St., London W1, UK; +(44) 20-8994-2890; fax: +(44) 20-8747-8711; e-mail: dzr@reinsteininstitute.com; Web site: www.ReinsteinInstitute.com.
Reference:
- Waring GO 3rd. A cautionary tale of innovation in refractive surgery. Arch Ophthalmol. 1999;117:1069-1073.