Eyeworld

AUG 2014

EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.

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EW FEATURE 40 by Maxine Lipner EyeWorld Senior Contributing Writer I n most LASIK or PRK cases, practitioners proceed with alacrity. But what about those less common instances involv- ing autoimmune disease, thin corneas, or those with irregularities such as keratoconus? When should you proceed with these and how can such cases best be approached? Autoimmune LASIK cases When it comes to patients with autoimmune disease, the concern is around corneal melting, according to Robert K. Maloney, MD, clinical professor of ophthalmology, Jules Stein Eye Institute, Los Angeles. The classic diseases causing trepidation include rheumatoid arthritis, Wegener's granulomatosis, and polyarteritis nodosa. The concern in performing LASIK in these patients has centered on whether doing LASIK will cause melting in the area of the flap, Dr. Maloney said. However, this has not been true in his experience. "We published a series a few years ago in which we had done LASIK on 49 eyes with autoimmune disease," Dr. Maloney said. "Eleven of the eyes had rheumatoid arthritis and 13 had lupus. None of the eyes developed corneal melting after LASIK." They concluded that the risk of corneal melting in those with autoimmune disease is low. In Dr. Maloney's view, LASIK is safe in these patients in certain circumstances. First, the patient's autoimmune disease needs to be well controlled. Second, the patient should not have significant dry eyes, which is a common contrain- dication for LASIK. Third, it is best if the patient is under 70 years old. Typically, reports in the literature involving autoimmune disease and corneal melting are in older patients with out-of-control disease, he said. "Younger patients with well- controlled disease are at much lower risk of corneal melting," Dr. Maloney said. In addition, availabil- ity over the last 10 years of Enbrel (etanercept, Amgen, Thousand Oaks, Calif.) and other immune modu- lators has improved the control of autoimmune diseases, he said. In the stable autoimmune patient without dry eye, Dr. Maloney feels confident in attain- ing good LASIK outcomes. "There is no evidence in our experience that patients with autoimmune disease have any different outcomes than those without, assuming they're carefully selected," he said. Combining PRK, riboflavin UV crosslinking Other patients who might not typi- cally be eligible even for PRK include those with thin or irregular corneas, according to Eric Donnenfeld, MD, clinical professor of ophthalmology, New York University Medical Center, New York. "The addition of ribofla- vin UV crosslinking opens up the opportunity to treat patients who in the past would not be considered eligible for laser vision correction because of the risk of ectasia," Dr. Donnenfeld said. "This will benefit patients significantly and reduce the risk of ectasia to a very low level." A. John Kanellopoulos, MD, clinical professor of ophthalmology, New York University, and director of Laser Vision.gr Institute, Athens, Greece, has studied riboflavin UV crosslinking over the last 12 years and touts its ability to halt ectasia progression. While it would also flatten the cornea 1 D to 2 D, this did not cause any dramatic changes in the patient's visual rehabilitation, he said. "Thus, early on, we ended up crosslinking a large number of patients who were not able to wear contact lenses, and we were com- pelled to perform a therapeutic topo-guided PRK intervention in order to normalize those corneas that had shown they were stable with time," he said. "That proved to be successful, and we have reported our initial and long-term data on hundreds of cases so far." The technique used is still evolving. When performing PRK and crosslinking, deciding whether these should be done at the same time or sequentially remains in question, Dr. Donnenfeld said. There is a benefit to doing these at the same time because the patient only needs to go through epithelial debridement once and the tissue being removed is not the strengthened crosslinked cornea. However, thin corneas undergoing laser treatment may be at increased risk for endothelial toxicity, he said. The addition of the riboflavin and the UV crosslinking can also contribute to delayed healing. "There's an added level of safety in performing the riboflavin UV crosslinking first and then coming back for the laser vision correction at a later time," Dr. Donnenfeld said. Still, with epithelial-on crosslinking now gaining traction in the U.S., without the issues associated with removing the epithelium twice, he currently frames this as an informed consent decision for patients in which he emphasizes that when done together, healing may be delayed. Dr. Kanellopoulos thinks that for those first getting started, it may be prudent to evaluate the crosslink- ing effects for at least 6 months and then, if need be, perform a partial topographic-guided PRK to normal- ize the cornea. An even "softer" start on this concept would be to perform CXL following excimer laser epithe- lial removal (PTK). As the epithelial remodeling is known to be thinner over the cone, the 50-micron PTK will act as a "soft" topo-guided normalization of the underlying stroma, and the epithelium post CXL is less irregular, adding to the normalization of these corneas and improvement in visual rehabilita- tion. In terms of healing, he said, by day 4, the majority of patients are epithelialized. However, when a de- lay occurs, it is important to address this because if it is left untreated, central corneal scarring can occur. "We tend to give autologous serum to all those patients to help with healing and maybe a bandage contact lens for a few days, even after the standard 4-day bandage contact lens is used." In extreme cases, he has used a freeze-dried amniotic membrane button overlay (IOP Inc., Costa Mesa, Calif.) to promote epitheliali- zation. Recently, he has tried a new agent by Thea Laboratories (Clermont-Ferrand, France). "That creates a polysaccharide membrane over the cornea that accelerates healing under it," he said. "We've seen early promising results." Newer technologies involving CXL, such as the CE marked KXL II device by Avedro (Waltham, Mass.), Keratorefractive surgery August 2014 AT A GLANCE • LASIK can be safe for some younger, stable autoimmune patients without complicating factors. • PRK with UV crosslinking can allow practitioners to treat those who were untreatable in the past with laser vision correction. • With topographic PRK and crosslinking, keratoconus patients can gain lines of vision and become eligible for spectacle or soft contact lens wear. LASIK and PRK cases in new focus While corneal melting has been associated with autoimmune disease in cataract patients, performing successful LASIK in this population is possible. Source: Anthony Aldave, MD

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