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LASIK Damage the Nerve Fiber Layer? "We've noticed, using the GDx Nerve Fiber Analyzer, that there is a dropout of between 5-15% of the total nerve fiber layer following LASIK in patients who have had the suction on the eye for 30 seconds or more," says Edward Yavitz, M.D., of the University of Illinois College of Medicine. "I only ran a group of 20 patients. But we had 20 out of 20 whose one eye showed nerve fiber thinning at one month. The opposite eye, which was treated by Alphagan, showed no loss." To create a uniform flap in LASIK, surgeons apply a suction ring that raises IOP to about 80-85mm Hg. The suction time—which varies from about 15-45 seconds depending on surgical skill and the type of microkeratome—may be a determinant of potential NFL thinning. Dr. Yavitz has found no nerve fiber loss (without Alphagan) in patients for whom the suction time was 20 seconds or less. In a separate study of 60 patients who received no Alphagan and had LASIK with suction times less than 30 seconds, New York surgeon Sanjeev Nath, M.D., likewise measured no significant nerve fiber loss on GDx. Perhaps the tool matters as well. A microkeratome housing an integrated suction ring may allow for a quicker pass than a less-wieldy two-piece unit. Dr. Yavitz and the other investigators in the multi-center study plan to use various microkeratomes to gauge the effect of different suction times. Skeptics initially questioned whether Dr. Yavitz's findings might simply be artifacts reflecting postoperative changes in the cornea, a medium of the polarization measured by the GDx. (The system features a corneal compensator.) Dr. Yavitz refutes the skepticism by noting the absence of nerve damage in the Alphagan-treated eyes. The larger study aims to reproduce his findings using the same protocol as the pilot series: Alphagan tid in one eye and placebo in the other for three days pre-op and one week post-op, with GDx measurements preoperatively and one month after surgery. Dr. Yavitz hopes to complete the study within about a year. In the meantime, should you warn patients about a possible risk of nerve fiber layer loss in LASIK? Dr. Yavitz thinks we should wait and see. After all, his was merely a small series of 20 patients. And remember, the GDx changes appeared only in cases where the suction time was 30 seconds or more. Besides, says Dr. Yavitz, the 5-15% NFL dropout measured in his patients may be clinically insignificant. The GDx measurements showed that, despite the loss, their NFL thicknesses remained within normal limits. "Since this is a patient population of high myopia, which is more prone to developing glaucoma later in life, we don't like to see any nerve fiber layer loss at this early age," Dr. Yavitz says. Studies suggest that patients can sacrifice 30-50% of their nerve fiber layer before the onset of visual field loss. Even with that leeway, TLC's J. James Thimons, O.D., considers the extent of NFL loss in the Illinois study cause for concern: "It means you've eaten up a third of the available nerve fiber layer before they show a field loss, according to some of the studies. That's a huge change in the normal anatomy and physiology of the eye." top
New Tactile Alphabet for the Blind May Be
Quicker Than Braille
Of the 4.3 million Americans who have severe visual impairment, only 85,000 use Braille, even for simple tasks, the Journal of Visual Impairment reports. Braille readers may require hours of instruction and lengthy practice to reach reading comprehension speed. In a study on ELIA, sighted students were able to read 8 words per minute after 11 hours of instruction. Dr. Elia Chepaitis is an engineering professor who used ergonomics principles to design the alphabet for her mother (also named Elia) who was an avid reader losing her vision to macular degeneration. ELIA could be useful for leisure reading, Mr. Chepaitis says. But he says it's primarily intended for functional tasks like labeling difficult-to-identify household items such as faucets, knobs or canned goods. Eventually, he hopes the new tactile alphabet could be used not only around the house but also on the job to improve employment opportunities for the visually impaired. top
Visx Loses First Round of ITC Fight Visx alleged that Nidek violated an ITC regulation that bars import of
goods that infringe on domestic patents. An ITC investigator found insufficient
evidence to support that charge. She also supported Nidek's claim that
a key Visx patent was invalid owing to "improper inventorship"—meaning
the ITC couldn't determine who should take credit.
The latter point pertains just to this case, says Lola Wood, Visx's manager
of investor relations. "[It] has no binding effect on other legal issues
or cases. The judge has no jurisdiction over patents. Only a district
court or the Patent and Trademark Office can invalidate a patent."
Even so, Ray Sayano, Ph.D., vice president and general manager of Nidek
Technologies Inc., thinks the case bodes well for his company's other
patent litigation with Visx, now pending in the California courts. "Though
there's always the possibility that the California courts won't find the
same way," Dr. Sayano says, "this certainly doesn't hurt our case, and
makes us more confident that we don't infringe." Optometry
Payments Increase In New Medicare Fee Schedule Nationwide, average fees for eye exams for new patients (92004) and established patients (92014) increased 3% and 4%, to $124.49 and $91.53, respectively. (Fees vary from one region to the next.) An intermediate exam for an established patient (92012) dropped 16%, to $63.71, now that certain supplies are no longer reimbursed. These rates reflect the Health Care Financing Administration's continued phasing in of its new practice expense formula. The formula, which took effect last January, shifts money away from facility-based specialties to office-based specialties, including optometry. Reimbursements likewise increased for the 99000 series evaluation and management (E/M) codes performed in-office. Fees climbed as well for extended ophthalmoscopy, foreign body removal, punctal plug insertion and visual fields, says Medicare consultant Heather Loveland, Hendersonville, Tenn. Reimbursement for punctal plugs declined. Expect less for cataract comanagement as surgical payments continue to fall. The national average for cataract removal and IOL insertion (66984) went down 6 percent, from $700.03 to $654.65. Also of note: HCFA revised its regulations to reflect provisions of the Omnibus Budget Reconciliation Act of 1986, which specifies that "Medicare Part B pays for the services of a doctor of optometry, acting within the scope of his or her license." OSHA's
Ergonomics Proposal OK with O.D.s—for Now
Optometrists should support proposed ergonomic workplace standards that
the Occupational Safety and Health Administration (OSHA) has published,
says at least one authority on computer-related vision disorders.
OSHA published the draft in the November 23, 1999, Federal Register,
and copies are available on its web site at www.osha-slc/ergonomics-standard/.
James E. Sheedy, O.D., Ph.D., president of CVS Doctors and a frequent
lecturer and author on computer vision syndrome (CVS), notes the draft
doesn't specifically mention optometrists or terms such as "eyes" or "vision."
However, the regulations would cover "musculoskeletal disorders."
"Considerable evidence exists to support that vision disorders
fit the definition of a musculoskeletal disorder—and it is certainly true
that proper vision correction can improve MSDs such as for presbyopic
computer users," Dr. Sheedy says in a position paper on the standards.
When OSHA held hearings on its standard in 1998, the AOA and PRIO Corporation,
which manufactures a computer simulator for the exam lane, told the panel
the standard should list CVS as a repetitive stress injury and recognize
O.D.s as physicians who can treat and diagnose CVS.
Now may not be the time for optometric interests to push for specific
language in the draft, Dr. Sheedy says. Besides his argument that the
language may be broad enough to include eye disorders, he also expects
employers to strongly oppose the draft standard. Indeed, a few weeks ago
OSHA announced it would extend the standards to home workers, only to
back off a couple days later after setting off a firestorm of opposition
from employer groups.
Much of the OSHA draft deals with physical ailments due to heavy lifting
and repetitive movement. However, OSHA says employers also would need
to fix other jobs in which employees experience work-related musculoskeletal
disorders. The provision would cover some 1.9 million work sites.
"Three-quarters of general industry employers would not need to do anything
until a documented, work-related injury actually occurs," says Charles
N. Jeffress, assistant secretary of labor for occupational safety and
health.
OSHA estimates 1.8 million U.S. workers experience work-related musculoskeletal
disorders a year, and a third of those injuries are serious enough to
require time off. Work-related musculoskeletal disorders account for one-third
of all workers' compensation claims paid. OSHA, meanwhile, is still accepting
comments on the draft. They're due by February 1, with informal public
hearings to begin February 22.
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