EyeWorld Asia-Pacific December 2013 Issue

37 EWAP rEfrActivE December 2013 709 M toric lens (Carl Zeiss Meditec, Jena, Germany) in stable keratoconus patients undergoing refractive lens exchange or cataract surgery, investigators were able to offer patients a significant boost in unaided vision. “In a nutshell, following the procedure, 75% had 20/40 uncorrected acuity or better, and with correction 83.3% had 20/40 vision or better,” Dr. Daya said. “Their mean refractive astigmatism went down from 3 D to 0.7 D, which is quite significant.” Likewise, he added, keratoconus patients are typically myopic, and here after lens implantation the mean spherical equivalent went from –4.8 D to +0.30 D. However, Dr. Daya stressed, phakic IOLs or refractive lens exchange is not for all keratoconus patients. “They have to have a history of good vision with their existing corneal shape,” he said. For those who can’t see well enough with glasses but who are stable, it is still possible to use this method. “If they can’t see with glasses then we would consider putting in an intracorneal ring or two (preferably a small radius Ferrara) to alter the shape so that they can have better vision that’s respectable with glasses and then consider refractive lens exchange,” Dr. Daya said. When dealing with refractive lens exchange in keratoconus cases, Dr. Daya advises practitioners to gather as much background as they can. “It’s like going into battle. You need as much information as possible,” he said. In cases where little history is available, he looks at the level of asymmetry of the cornea using 3 D topography, and he talks to the patient about his or her use of glasses in the past and ascertains how long the keratoconus has been stable. In addition, he contacts patients’ optician to get a history of their refractions and visual acuity. Only then, he said, is he comfortable proceeding with cataract surgery or refractive lens exchange. Overall, in Dr. Trattler’s view, patients with keratoconus now have a plethora of refractive opportunities. “I think that patients with keratoconus have more options and avenues for improving vision than they ever had before,” Dr. Trattler said. “Surgeons should be aware of the many options for their patients, especially those who have difficulty tolerating contact lenses.” EWAP Editors’ note: Dr. Daya has financial interests with Bausch+Lomb (Rochester, NY, USA), Carl Zeiss Meditec, TearScience (Morrisville, NC, USA), PRN (Plymouth Meeting, Pa., USA), and SARcode Bioscience (Brisbane, Calif., USA). Dr. Trattler has financial interests with with CXLUSA and CXLO. Dr. Lee has financial interests with Allergan (Irvine, Calif., USA) and Bio-Tissue (Miami, Fla., USA). contact information Daya: +44 1342 306020, sdaya@centreforsight.com Lee: +1-646-342-5546, jimmylee@montefiore.org trattler: +1-305-598-2020, wtrattler@earthlink.net in their corneal shape, and their main option would be topography- guided surface ablation, which is available in Canada and Europe. Topography-guided surface ablation incorporates data from corneal topography into the treatment plan, allowing this technology to reshape corneas that are asymmetric, which is the typical case for keratoconus or post-LASIK ectasia patients. The goal, he explained, is to normalize the shape and improve the quality of vision. Meanwhile, Dr. Lee thinks that this sort of topographic approach may one day be extended to crosslinking with the ability to specify where the crosslinking light is distributed. toric lens implantation Toric lens implant surgery is another possibility of which practitioners are availing themselves, according to Sheraz Daya, MD , medical director, Centre for Sight, London, UK. This can be done with phakic toric lenses such as the Artiflex (Ophtec, Groningen, the Netherlands), the Toric ICL (STAAR Surgical, Monrovia, Calif., USA) or by refractive lens exchange using toric intraocular lenses. “In patients who are older, if they have a whiff of a cataract or are around age 55, a refractive lens exchange with a toric implant is a good option,” Dr. Daya said. Indeed, in a study published in the December 2012 issue of the Journal of Refractive Surgery involving use of the AT Torbi PrK for keratoconus Another refractive technology that is being used in conjunction with intracorneal ring segments is PRK. “In the pas t, people have been very reluctant to touch or aggressively work on the cornea for keratoconic patients because the corneal tissue is unstable,” Dr. Lee said. The recent advent of crosslinking to strengthen the cornea and potentially halt keratoconus progression has helped to change this. “People have looked at combinations of crosslinking with these intracorneal ring segments or crosslinking plus or minus the PRK,” he said. “The preliminary data seemed to show that it is very promising.” William B. Trattler, MD , director of cornea, Center for Excellence in Eye Care, Miami, Fla., USA, likewise noted that crosslinking has had an important impact. “Crosslinking is a technology that stiffens the cornea and often improves corneal shape. Following crosslinking, patients are typically eligible for corneal reshaping procedures such as surface ablation,” Dr. Trattler said. In his practice, a small percentage of patients with keratoconus or post-LASIK ectasia who undergo crosslinking can end up with a relatively symmetrical corneal shape, allowing them to become eligible for surface ablation with technology available in the United States. This is because the excimer lasers in the U.S. provide symmetrical reshaping of the cornea. However, most patients still have significant asymmetry Refractive - from page 35