EyeWorld Asia-Pacific December 2013 Issue

8 December 2013 EWAP FEAturE Diagnostic - from page 7 readings is likely a result of an unstable ocular surface, he said. Dr. Crotty added any patient with an irregular ocular surface is deferred for treatment; more severe ocular surface disease, such as those with degenerative scar tissue may even require superficial keratectomy to improve the outcomes of cataract surgery. Dr. Wallace relies on his whole team to sign off on all charts, calculations, and even toric IOL choices before the preop evaluation is considered complete. “There have been times when one of us has caught a mistake that would have resulted in a poor visual outcome,” he said. Flow of events With normal topography, using the K readings from an IOLMaster “works quite well,” Dr. Waltz said, but the device will only check a limited number of points. Comparatively speaking, the Lenstar checks 32 points, “so it enhances your ability to pick an IOL correctly.” Dr. Trattler opts to bring patients back for a second reading to reconfirm the initial findings and rolls the costs into his premium packages. Dr. Yoo performs the topography and wavefront aberrometry in the clinic, but the IOLMaster readings are reserved for the preop exam day (as the device is not in the clinic). Dr. Horn prefers the Lenstar and allows for a small amount of deviation (less than –0.2 D for the astigmatism and less than 3 degrees for the axis), and uses the Holladay II formula for IOL calculations. “The iTrace [Tracey Technologies, Houston] is a great diagnostic device to decide where the aberrations are coming from to quantify the astigmatism,” Dr. Waltz said, noting the device’s ability to superimpose the image with the topography to help ensure lens positioning is correct in the OR. Cost issues Toric lenses are more expensive, and these diagnostic tools have a hefty price tag as well—but not really, Dr. Waltz explained. For practices converting 10% of their cataract patients to premium lenses, the cost involved with the extra diagnostic devices is rapidly returned. If surgeons only perform 100 or so cases a year, even with an enhancement rate of 10% “that’s only 10 cases a year, so you probably deal with it and move on. But once a practice is at 1,000 procedures a year, now that 10% enhancement rate results in 100 cases, and you’ll need to drive down those rates,” he said. “As the rate of toric and multifocal IOLs increases, spending larger amounts of money on better technology to reduce enhancement rates makes a lot of sense.” Dr. Waltz believes more cataract specialists need to start thinking like their refractive specialist counterparts. “When my LASIK enhancement rate was 30% I wasn’t as concerned with enhancements because I expected them. But when my LASIK enhancement rate dropped to 10%, patients were more upset about needing an enhancement and I was more concerned. Now that my LASIK enhancement rate is 2%, those patients who need enhancements think I did something wrong. So, paradoxically, I work harder to further reduce my 2% enhancement rate than I did to reduce my 30% enhancement rate. This paradox also explains why cataract surgeons are so concerned by a relatively small enhancement rate with toric IOLs. They are used to an almost zero enhancement rate with routine monofocal IOLs,” he said. Investing in more sophisticated technology will decrease the enhancement rates after toric IOL placement and result in a net decrease in costs and an improvement in surgeon and patient satisfaction, he said. Post-refractive surgery patients Everyone agreed that getting a true refraction in a post-refractive surgery patient is a bit trickier than in a virgin eye, but the amount of preop tests doesn’t differ. “The biggest challenge in these eyes is getting the correct IOL power,” Dr. Yoo said. Dr. Trattler opts to use the Haigis-L formula, calling it “very effective” in these eyes to the point that “I don’t worry about the preop data. I just use the Haigis-L and have found it consistent in post-RK and post-LASIK eyes.” However, he will pay more attention to the optical zone and the centration of the optical zone depending on how far back the patient underwent refractive surgery. Because these are patients who previously paid out of pocket to reduce, if not eliminate, their need for glasses, “expectations are going to be higher when it comes to their cataract removal,” Dr. Wallace said. As Dr. Waltz noted, it’s not the quality of the preop testing that changes in post-refractive patients, “it’s the discussion. We need to prepare this patient group and educate them about the difficulty in choosing an IOL and the potential for enhancement surgery.” Dr. Wallace does not treat 0.75 D or less of against-the-rule corneal astigmatism “because the incision is going to have some effect. We’ll talk to the patient about it, but counsel against addressing it. If the astigmatism is oblique or with the rule, we are going to be a little more aggressive in treatment.” Dr. Horn added posterior corneal astigmatism may play a role in some cases, too, noting cases where removing the cataract alone addressed the astigmatism because it was all in the lens. Toric lenses add about US$400- 500 to the cost of the overall package, and the patient has to purchase the lens. “If it’s just the astigmatism that needs to be corrected, I prefer toric lenses to limbal relaxing incisions,” Dr. Horn said. “LRIs are subject to healing responses and may interfere with tear film and ocular surface disease issues.” Dr. Wallace presents both options to patients, noting the LRIs are a less expensive option than a toric lens. Dr. Yoo agreed, saying she may opt for an intrastromal incision or an LRI if the patient has a small amount of astigmatism, but in general she prefers toric lenses simply because cutting the corneal nerves may exacerbate dry eye in the typically older population. EWAP Editors’ note: Dr. Crotty has financial interests with Allergan (Irvine, Calif., USA) and Bausch+Lomb, (Rochester, NY, USA). Dr. Horn has financial interests with Alcon (Fort Worth, Texas, USA/Hünenberg, Switzerland) and Haag-Streit. Dr. Trattler has financial interests with Allergan, Abbott Medical Optics (AMO, Santa Ana, Calif., USA), Bausch+Lomb, and LENSAR (Orlando, Fla., USA). Dr. Wallace has financial interests with AMO, Bausch+Lomb, and LENSAR. Dr. Waltz has financial interests with AMO, Hoya (Tokyo, Japan), and Tracey Technologies. Dr. Yoo has no financial interests related to this article. Contact information Crotty: rcrotty@wallaceeyesurgery.com Horn: +1-615 329-9575, Jeff.Horn@bestvisionforlife.com Trattler: wtrattler@gmail.com Wallace: bwallace@wallaceeyesurgery.com Waltz: kwaltz56@gmail.com Yoo: +1-305-326-6322, syoo@med.miami.edu