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February 26, 2007
Today’s refractive surgery trends : Safety
Eyeworld Feb 2007
Surgeons are taking safety steps to avoid ectasia by measuring flap thickness intra-operatively, creating thinner flaps, and preferring a higher stromal thickness.
The ectasia concern remains despite 60% of respondents reporting having never seen a case of post-LASIK ectasia among their patients. Sixteen percent reported that they have had one case, and 12% have seen two.
“People are more concerned about ectasia and malpractice issues,” said Perry S. Binder, M.D., San Diego. “Therefore, we’re seeing more doctors say ‘I want my residual thickness to be greater than 250 microns.’” In fact, 18% of surgeons last year said they would prefer a residual stromal thickness of 275 microns; 17% would prefer 300 microns. The majority of respondents still feel comfortable with 250 microns, although that percentage has decreased as the higher numbers have increased.....The percentage of surgeons that measure flap thickness intra-operatively increased from 31% in 2004 to 35% in 2006, reflecting another safety trend. Still, Dr. Duffey was surprised that more growth has not occurred in that area. “To me it’s such a critical point…I keep expecting the numbers to be 50%, 75%, or even 90%, but it’s not,” he said.......Respondents also said they prefer thinner flaps, with 53% targeting 120 to 130 microns. In 2004 and 2005, a higher percentage preferred 150 to 160 microns.
The safety issue is also connected to the quest for better visual quality, Dr. MacRae believes......“With a thinner flap, there’s more room to do a larger optical zone,” he said.....The trend toward thinner flaps has pushed the growth of IntraLase (now AMO, Santa Ana, Calif.) technology, Dr. Duffey said. Furthermore, studies he has conducted have shown better predictability with thin flaps made by both IntraLase as well as mechanical microkeratomes. The bottom line: “The predictability gets better the thinner [the flaps] get,” Dr. Duffey said.....Forty-eight percent of surgeons prefer a central corneal pachymetry of 500 microns for LASIK. “Surgeons are afraid to operate on 500 microns or less, although there is no scientific evidence to say these increase or decrease the risk for ectasia,” Dr. Binder said
Posted by mehdi khanlari at February 26, 2007 11:09 PM