EyeWorld Asia-Pacific June 2016 Issue

40 June 2016 EWAP CATARACT/IOL by Louise Gagnon EyeWorld Contributing Writer New generation of IOLs to correct presbyopia Surgeon discusses a multitude of IOL options for presbyopia correction at the Walter Wright Symposium in Toronto S peaking at the 55th annual Walter Wright Symposium in Toronto, Sheraz Daya, MD , medical director, Centre for Sight, London, said that most well- selected patients who receive IOLs to treat presbyopia are very satisfied with their outcomes; a minority will complain of issues like difficulty driving at night. “About 10% of patients initially complain of night vision trouble, but this becomes less of a problem as they adapt,” Dr. Daya said. “We have very good lenses that improve the range of focus.” Dr. Daya, speaking about diffractive lenses and division of light energy, questioned if it is necessary to have 100% energy at a single focal point and asked to what degree energy is reduced by the presence of cataracts. “Do we need 100% for both reading and distance?” Dr. Daya asked. “The reality is that 100% is not required.” Reviewing the history of IOLs developed to correct presbyopia, Dr. Daya noted that the performance of accommodative lenses could theoretically improve with the inclusion of a dual-optic design linked by spring haptics, citing the Synchrony dual-optic accommodating IOL (Abbott Medical Optics, Abbott Park, Ill.) as an example of such an IOL. The Synchrony IOL, however, has not stood the test of time in performance and seems to have fallen out of favor, Dr. Daya said. The WIOL (Medicem, Prague) is an accommodative IOL that is made of hydrogel and presents advantages such as glare-free optics, resistance to posterior capsule opacification, position stability, and improved uncorrected vision at far, intermediate, and near distances. Despite the lens being large (7.0 mm partially dehydrated), it is implantable through 2.6 mm and in the bag grows to full size at 9.0 mm. “The view into the eye at a dilated examination is exceptional,” Dr. Daya said. Other IOLs that have been used to correct presbyopia include zonal, refractive lenses such as the M-Plus (Oculentis, Berlin). “It acts like a bifocal lens,” Dr. Daya said, noting the SBL-3 (Lenstec, St. Petersburg, Fla.) is similar in design. The asymmetric shape of the M-Plus created poor optics for patients, who complained of diplopia as well as glare at night and difficulty with night driving, said Dr. Daya, who has implanted 248 such lenses. The solution he put forth was to place the lens in an upside down position so that the glare would go upward and away from the road, but his patients then reported that they did not have good near vision. Trifocal diffractive lenses include the FineVision (PhysIOL, Liege, Belgium), the AT LISA 4ri #arl :eiss -editec *ena Germany), and the PanOptix (Alcon, Fort Worth, Texas), and they are developed using the Huygens-Fresnel principle whereby the plane wave is changed into an infinity of secondary spherical waves after diffraction. In terms of diffractive steps, the width of the step determines the addition of power such that the narrower the steps are, the higher the addition of power, and the wider the steps are, the smaller the addition of power, Dr. Daya explained. In terms of energy, the step height dictates the FineVision trifocal diffractive IOL Source: Sheraz Daya, MD