Controversy surrounds precise corneal molding

Issue: March 1996

MEMPHIS—Precise corneal molding (PCM) has generated controversy since its emergence several years ago. Proponents cite excellent results and say it safely corrects even high levels of myopia, a step beyond orthokeratology. Opponents are concerned both by safety questions and the way PCMhas been marketed.

mugshot --- J. Mason Hurt, OD.

The optometrist who said he developed PCM here 31/2 years ago, J. Mason Hurt, OD, said it is a new procedure based on ortho-K principles, in that rigid lens wearing can modify the cornea’s shape. But PCM uses corneal topography to precisely guide the shaping of the cornea, increasing the degree of myopia that can be corrected.

However, Roger L. Tabb, OD, chair of the International Society of Orthokeratology, said, "It’s pretty easy to prove that orthokeratology and precise corneal molding are one and the same. It’s just that precise corneal molding is a term that was used to figure out a way to market it."

"Very little empiricism"

Hurt said he started out practicing ortho-K, but there was "very little empiricism. You basically put a flat lens on and just try to flatten the cornea." Because the emphasis in ortho-K is on power, he said success is limited to 2 D or 3 D of correction.

By focusing on shape instead of power and working with the whole cornea instead of the center, Hurt said he found higher amounts of myopia could be eliminated. "If we control how we modify the shape of the cornea, power will follow," he said. Most PCM patients are between –5 D and –8 D, he said.

PCM is also so effective because the shape is displaced inferiorly; this complements upper lid action, he said. "In PRK (photorefractive keratectomy), RK and particularly ortho-K, the displacement of shape works against the upper lid, inducing instability and causing shorter periods of success."

mugshot --- Rodger T. Kame, OD.

Rodger T. Kame, OD, a contact lens practitioner in Los Angeles, said while he grants the possibility of correcting higher levels of myopia, "to me, they’re practicing ortho-K, but to an extreme. I know that safely a certain amount of change can take place and not expose the eye to potential irreversible problems. There is a judgment call here."

To teach others about PCM, Hurt conducts educational seminars. David O. Peed, OD, of Columbus, Ga., said he attended a seminar at which Hurt claimed to have developed a proprietary lens and required ODs to buy equipment: a corneal topographer and digital image capturer. But PCM "did not work like they said it would" for high myopes and hyperopes, Peed said. "My problem comes from the exorbitant claims that were made for something that is not proprietary."

Hurt contended that he never said the lenses were proprietary, but "my procedure is proprietary. We don’t share all the different curves and how we do them."

And the digital capturer is optional, but corneal topography is "essential" to PCM, he said. Without topography, "I’m back to ortho-K because I have no idea where I’m placing the shape."

Marketing complaints

Hurt enlisted the aid of a marketing company, PCM Media, and its efforts have been the source of complaints. The company was to work in an OD’s market and the optometrist would, in turn, pay the company per procedure. Peed said PCM Media tried to charge ODs up front for "overexaggerated marketing" that was never fully delivered.

As a result, Peed said he, like others, is stuck in a lease for equipment. "The finances that were presented to me that justified buying a topographer failed to materialize at the office level," Peed said. "I feel that the marketing people really took advantage of a lot of ODs."

Missouri’s Vince H. Coburn, OD, said some ODs had not paid the marketing company, and the company’s response was to cut off all ODs indiscriminately, including himself. "There’s no doubt we were over promised what the potential for it was," he added.

Hurt conceded there were problems with the marketing. He said some ODs did not pay, and PCM Media "tried to do things that didn’t work out. The marketing was inept." It "was a disaster" for all sides, he said, but "no one lost more money than I did. No one has the right to complain as much as I do."

Hurt discontinued his relationship with the company, which he said is now defunct. (There is no listing for the company in the Memphis area.)

Kame said all this could damage ortho-K’s reputation. Until the recent work of University of Indiana researcher Douglas Horner, OD, PhD, Kame said good research on ortho-K had not been done since the 1970s. "Ortho-K has a bad name, because everything is anecdotal." Now that ortho-K is gaining acceptance, he said, "if PCM creates a controversy, those who had been unwilling to accept ortho-K might say, ‘See, I told you it is still a fringe procedure.’"

PCM results

What about PCM’s results? Indiana’s Horner is skeptical: "Where is the research data that suggests this even works? I’m sure there’s no referred literature investigating this procedure."

mugshot --- Robert A. Schwab, OD.

While research is scant, many describe good results in practice. Hurt said his success rate is 92%. Ohio’s Robert A. Schwab, OD, who had done ortho-K for 25 years, said he has had remarkable success and has done PCM in several hundred patients.

Frank A. Joslin, OD, in private practice in Florida, said he has had success up to 4 D of myopia in the dozen patients he has seen, but has had trouble "totally reducing nearsightedness" beyond that. However, he said, "overall, it’s much better than anything we’ve had before as far as ortho-K is concerned."

Hurt said ODs who have had trouble with higher myopes must realize that PCM takes a high level of practitioner skill and patient compliance. "If we find the right doctor and he or she finds the right patient, it’s guaranteed success," he said. And the growth of refractive surgery will help PCM: "I would say within 5 years all post-surgical patients will be wearing molds," Hurt added.