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48 EW SECONDARY FEATURE Doubling continued from page 46 Preliminary results of the study show no difference thus far between the two with regard to the outcome of corneal flattening and corneal stabilization, he said. Dr. Hersh said that over 90% of keratoconic patients in his studies so far are stabilized, although approxi- mately 5% of them continue to progress despite the crosslinking. With regard to visual acuity, most patients remain stable and in fact, a number get better vision, he said, although a small percentage of patients can lose a small amount of visual acuity. With Intacs, some patients may complain of glare from optical rea- sons or because of infection or in- flammation, and the Intacs would need to be removed. In his afore- mentioned study, though, there was no need for Intacs removal, he said. Indications for this combined procedure would be patients who are contact lens intolerant with poor spectacle-corrected vision, with the intention to improve the corneal topography for better contact lens tolerance or spectacle tolerance, Dr. Hersh said. The contraindications would be patients whose corneas are too thin (less than 400 µ) for either the crosslinking or Intacs procedure and patients who have corneal scarring, which would preclude an advanta- geous visual response to the proce- dures, he said. Crosslinking and LASIK In order to ameliorate the risk of ec- tasia after LASIK, some surgeons in Europe have also begun employing corneal crosslinking following the refractive surgery, with reportedly good results so far, Dr. Hersh said. Patients who may have a greater risk of corneal ectasia include those with thinner corneas or higher cor- rections, and there are investigators who have incorporated this for hyperopic procedures, which may tend to be less stable over time as well, he said. Dr. Kanellopoulos, who per- forms this combination surgery, said, "We currently use as an indica- tion any patient who's under 35 years old with myopia over 6.0 D and any patient with astigmatism over 1.0 D." In a paper presented at the 2012 ASCRS•ASOA Symposium & Congress in Chicago, Dr. Kanellopoulos and colleagues reported the results of a contralateral eye study where one eye had stan- dard hyperopic LASIK and the other had hyperopic LASIK with prophy- lactic collagen crosslinking. The study showed statistically significant evidence that the latter group preserved steeper corneal effect consistent with the stability of the initial hyperopic correction, Dr. Kanellopoulos said. Besides the extra time and ex- pense involved in this procedure, Dr. Kanellopoulos said there aren't re- ally any drawbacks. However, con- traindications include ultrathin flap LASIK. Flaps that are under 100 µ may get some wrinkling because some of the riboflavin solution soaks into the flap and may result in microstriae, he said. With most LASIK studies reporting that the biomechanical stability of the cornea inherently weakens by 20% in the long term, Dr. Kanellopoulos said that the pro- phylactic application of corneal crosslinking will only benefit the long-term behavior and stability of the cornea in LASIK procedures. EW Editors' note: Drs. Hersh and Kanellopoulos have no financial interests related to this article. Contact information Hersh: 201-883-0505, phersh@vision-institute.com. Kanellopoulos: +30 21 07 47 27 77, ajk@laservision.gr February 2011 Crosslinking August 2012