EyeWorld Asia-Pacific June 2012 Issue

June 2012 13 EWAP FEATURE (Carl Zeiss Meditec, Dublin, Calif., USA/Jena, Germany) topographers “in all the formulas on the ASCRS website. Once I have a range of IOL powers—usually about 2-2.5 D—I bracket these IOL powers and have them all available in the OR (there’s actually a plastic basket full of IOL boxes on the back table).” About 33% of post-refractive surgery patients who need cataract surgery present without any historical records, said Uday Devgan, MD , chief of ophthalmology, Olive View- University of California, Los Angeles Medical Center, Sylmar, Calif., USA. “If they have no records, do your best to get as much pre-op data as possible. Ask a spouse if there are old contact lenses or spectacles around. If not, ask [patients] if they remember how far away they had to hold a book to read it clearly.” In these eyes, Dr. Devgan also suggested using the ASCRS calculator, but warned surgeons need to clearly explain to patients they’ll be estimating on lens power in post-surgical eyes with no historical data. “The [patients have] to understand they will likely still need spectacles,” he said. Dr. Raizman agreed. “No patients will be happy with a hyperopic outcome, but they’ll be OK if there’s minor myopia.” He also opts for a three-piece lens and a slightly larger capsulorhexis in this group. “There’s no magic bullet formula” for IOL calculations in post-surgical eyes, Dr. Ashrafzadeh said. He uses Haigis L, Holladay II IOL Consultant, and the ASCRS calculator. “[Using a combination of] the modified Masket on the ASCRS calculator along with the other two seems to give the best predictions.” In post-hyperopic LASIK patients, “be very careful about treating ‘astigmatism’ in these eyes,” Dr. Devgan said. “You may mistakenly treat what’s not really there.” “Laser surgery did not correct only the corneal abnormalities, but also likely a not-so-infrequent lenticular component that will lurk when the crystalline lens is removed,” Dr. Ashrafzadeh said. Former myopes can have “practically all forms of implants, including multifocal IOLs,” he said, but he excludes multifocal options for former hyperopes. The post-RK eye Dr. McDonald said a study showed the flatter keratometric values between K and the 2-mm zone from the Orbscan (Bausch + Lomb, Rochester, NY, USA) have provided the best calculations. “The 2-mm spot has been the closest for us,” he said. “In post-RK, we’ll still take the lowest K reading. I shoot for a –1 in these patients.” Calculators “will always remain a vital part of pre-op evaluation,” Dr. Ashrafzadeh said. “Live aberrometry may augment the information. With the advent of optical coherence tomography technology and the ability to better image the anterior segment with greater accuracy, our precision in calculating the effective lens position will greatly increase.” Post-RK “has to be treated differently,” Dr. Devgan said. “There aren’t as many methods to calculate IOL powers for post-RK. They’re not stable eyes—the diurnal fluctuation in post-RK can be as much as 2 D different at the time of surgery.” “The post-RK eye is often impossible to calculate,” Dr. Raizman said. “It may be impossible to get an estimated corneal power. In those eyes, I like to think ahead and be prepared for an IOL exchange.” EWAP Editors’ note: Dr. Ashrafzadeh has financial interests with Carl Zeiss Meditec. Dr. Devgan has no financial interests related to this article. Dr. McDonald has financial interests with Bausch + Lomb and WaveTec Vision (Aliso Viejo, Calif.). Dr. Packer consults for industry and holds an equity stake in WaveTec Vision. Dr. Raizman has no financial interests related to this article. Cont act info rmation Ashrafzadeh: drash@modestoeyecenter.com Devgan: +1-800-337-1969, devgan@gmail.com McDonald: +1-479-521-2555, mcdonaldje@mcdonaldeye.com Packer: +1-541-687-2110, packer@finemd.com Raizman: mraiz@comcast.net Custom - from page 11 Tel: +65 64936953 Fax: +65 64936955 commercially available, but I think it will be toward the end of 2012 as a one-box machine that will be able to give you all these measurements together and give you more elegant topography and wavefront.” In Europe, surgeons are using the fourth generation of the Wavelight platform called Vario, which incorporates different pupil sizes on the topography and transfers that data for the laser to use. Iris recognition and limbal anatomy are also used as landmarks to perform the treatment, as well as correct for cyclorotation. “We’re seeing very good results with this, but I have to mention that it’s extremely rare that cyclorotation is a big issue,” Dr. Kanellopolous cautioned. For improvements, Dr. Probst said the tracking on the excimer lasers could be better. “They are designed to work on the reflecting surface of the cornea, but not on the bed of a LASIK flap,” he said, adding that he would also like to see a higher tracking speed and a better way to use the LASIK interface. Dr. Goldman said wavefront- guided and wavefront-optimized platforms are top-notch today. “We’ve already raised the bar so high with what we can do, which is a great thing, but we’re always looking for more improvement. The ways of us improving are faster lasers, faster capture rates, and smoother ablations.” EWAP Editors’ note: Dr. Goldman has no financial interests related to this article. Dr. Kanellopoulos has financial interests with Alcon. Dr. Probst has financial interests with AMO. Cont act info rmation Goldman: +1-561-515-1543, dgoldman@med.miami.edu Probst: +1-708-562-2020 Kanellopoulos: +30-210-74-7277, ajk@laservision.gr