Eyeworld

FEB 2012

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

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72 EW FEATURE February 2011 PRESBYOPIA February 2012 Correcting presbyopia at the cornea by Jena Passut EyeWorld Staff Writer Several prospects are on the horizon F years. Currently, monovision LASIK, which is performed in non-cataract patients and creates a distance focus in one eye and near focus in the other, is the only FDA-approved corneal procedure for presbyopia. But several exciting prospects on the horizon have kept surgeons waiting. Of the techniques being used for corneal correction of presbyopia, ex- perts discussed with EyeWorld which ones would become the "standard of care" in the next 5 years. or many clinicians—and patients, too—the options for surgical correction of presbyopia have remained just out of reach for several PresbyLASIK and INTRACOR (Technolas Perfect Vision, St. Louis) are based on creating multifocality in the cornea, while corneal inlays usually are inserted under a LASIK flap to improve near vision by in- creasing the depth of focus or creat- ing a central myopic area in the eye. PresbyLASIK PresbyLASIK is performed with an excimer laser to reshape the cornea into zones for near, distance, and in- termediate vision, which allows a patient to regain good vision at all distances. Pioneer Roberto Pinelli, M.D., scientific director, Istituto Laser Mi- crochirurgia Oculare, Crystal Palace, Brescia, Italy, believes presbyLASIK is the future, for very simple reasons. "LASIK is a worldwide-recog- nized technique with a long follow- up, and it is the most performed re- fractive procedure in the world," Dr. Pinelli said. "We have 7 years of re- sults from presbyLASIK. It's stable. When you do the surface of the cornea, you give intermediate and near vision because you restimulate the crystalline lens to accommodate. It's something that is working." Presbyopes who have not yet developed cataracts are potential presbyLASIK candidates, and the ex- cimer laser ablation also accurately corrects astigmatism. "If you make the cornea more aspheric and play with the negative spherical aberrations and high-order aberrations, you can replicate a young eye during accommodation," Dr. Pinelli said. Corneal inlays Jay S. Pepose, M.D., director, Pepose Vision Institute, and professor of clinical ophthalmology, Washington University School of Medicine, St. Louis, believes corneal inlays are most likely to become available in the U.S. "Problems with INTRACOR are The Flexivue Microlens, as viewed under a slit lamp, is under investigation in the U.S. Source: Ioannis Pallikaris, M.D. lack of reversibility and lack of long- term follow-up with a uniform tech- nique," he said. "PresbyLASIK has issues related to multifocality. The center near ablations generally re- duced distance vision too much, and the peripheral near sometimes in- duced unwanted aberrations in the pupil region due to an overlap in the optical and transition zones or in- duction of spherical aberration. Newer laser algorithms continue to be advanced, but long-term results with hyperopes, myopes, and em- metropes are wanting." Three devices are under investi- gation in the U.S.—the Flexivue Microlens (Presbia, Los Angeles), the KAMRA (AcuFocus, Irvine, Calif.), and the Vue+ (Revision Optics, Lake Forest, Calif.). A study in the Journal of Refrac- tive Surgery recently reported that the KAMRA corneal inlay improved near visual acuity with very little impact on uncorrected distance visual acu- ity or mesopic contrast sensitivity in the implanted eye.1 The prospective, nonrandom- INTRACOR treats the corneal stroma with a femtosecond laster Source: Technolas Perfect Vision ized, multicenter clinical trial was undertaken in presbyopic em- metropes ages 45-60. "Monocular mean uncorrected near visual acuity was J8 (0.482± 0.925 logMAR) preoperatively, J3 (0.185±0.848 logMAR) at 1 month (n=506, P<.0001), and J2 (0.139± 0.851 logMAR) at 18 months (n=99, P<.0001)," according to the abstract. "Mean uncorrected inter- mediate visual acuity was 20/35 (0.239±0.837 logMAR) preopera- tively and 20/26 (0.139±0.853 log- MAR) at 18 months (P<.0001). Mean uncorrected distance visual acuity (UDVA) was 20/20 (0.011±0.890 logMAR) at 18 months. Photopic (P<.001) and mesopic (P<.0001) monocular contrast sensitivities were within the range of the normal population at 1 year." INTRACOR Mike P. Holzer, M.D., associate pro- fessor and director, refractive sur- gery, University of Heidelberg, Germany, believes INTRACOR will be the future of presbyopic treat- ment. Dr. Holzer reported long-term clinical outcomes of the INTRACOR flapless intrastromal presbyopic treatment at the Asia-Pacific Associa- tion of Cataract and Refractive Sur- geons meeting in Seoul, Korea, this past October. INTRACOR uses the femtosec- ond laser to create multifocality in the cornea by allowing the surgeon to focus the laser beam at a specific depth without cutting the corneal surface, Dr. Holzer said. "INTRACOR is a refractive treatment that is done within the stroma," he said. "It [intends] to keep the corneal surface as well as Bowman's membrane intact. You don't dissect that, therefore the post- operative healing time is really quite great." With INTRACOR, the surgeon focuses the femtosecond laser beam directly into the mid-stroma, with consecutive rings being formed without dissecting or cutting the corneal epithelium or Bowman's or Descemet's membrane, which leads to a change in post-op corneal re- fraction. INTRACOR flattens or steepens the cornea according to an applied pattern of stromal ablations, which creates a type of magnifying glass in front of the eye. continued on page 74

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