EyeWorld Asia-Pacific June 2013 Issue

43 EWAP rEfrActivE June 2013 Source: Geunyoung Yoon, PhD Exploring HOA correction for keratoconus patients by vanessa caceres EyeWorld contributing Writerr Efforts from one lab target keratoconus patients, potentially other markets P recise with keratoconus are known to have problematic higher- order aberrations (HOAs) because of the shape of their corneas. Technology under development is aiming to help treat the HOAs that can mar these patients’ visual quality. At the University of Rochester, Flaum Eye Institue, in Rochester, NY, USA, Geunyoung Yoon, PhD , lab director, Advanced Physiological Optics Laboratory, has helped lead research on the use of a customized soft contact lens that corrects keratoconus patients’ specific HOAs. The research began in 2002, when the National Institutes of Health began to support the development of such a lens. Bausch + Lomb (Rochester, NY, USA) fabricates the contact lenses used by Dr. Yoon’s lab. Then, developers in the lab use wavefront-guided technology to customize the lens for each individual. The contact lens, for now only available in the lab and for research purposes, is made just as a regular soft contact lens is made, Dr. Yoon said. Patients care for the lens in a similar manner as other soft contact lenses. “The only difference is the optical design,” Dr. Yoon said. “We need to know the higher- order aberrations each patient has, measure the aberrations. This is a 100% customized design.” Although the main target for the lens is keratoconus patients, those who have recently had penetrating keratoplasty can use it as well, Dr. Yoon said. challenges However, one challenge with the lens is tracking decentration and rotation. Since soft contact lenses naturally slide over the ocular surface every time patients blink, lens developers have to understand and account for positional stability. Another challenge is cost. Although this kind of customized contact lens could be expensive for patients, if commercially developed, lens developers may consider selling a year’s supply at a time to patients, Dr. Yoon said. This could make the manufacturing process easier and the cost to the patients less. For now, the HOA-correcting lens is not available through a commercial manufacturer, although some companies have been approached with the idea. Although the use of a soft contact lens instead of a hard lens in keratoconus patients—combined with the HOA corrections—is an exciting prospect for manufacturers, some are skeptical about investing in what is a small potential market, Dr. Yoon said. Other uses The HOA-correcting technology has other possible uses. At the Boston Foundation for Sight, physicians are always looking for better ways to improve vision for patients with complex corneal diseases, said Deborah S. Jacobs, MD , medical director, continued on page 45