Eyeworld

EW REFRACTIVE SURGERY 52 August 2015 by Michelle Dalton EyeWorld Contributing Writer may benefit from a YAG laser treatment if there's any PCO or capsular fibrosis; and patients with hyperopia after cataract surgery may do better with a piggyback IOL (or IOL exchange) since hyperopic PRK is "not that great." A small degree of hyperopic LASIK (up to +2 D) is acceptable, he said; the most critical point: The refraction that makes the patient happy in trial frames is "the exact treatment that we want to do with the excimer laser." When it comes to the nitty-grit- ty of what's on the laser, Sonia H. Yoo, MD, professor of ophthalmol- ogy, Bascom Palmer Eye Institute, Miami, said she prefers a fast, small spot laser that will give a smooth ab- lation, and considers a pupil-track- ing feature necessary as it keeps the ablation centered. "I like the ability to change the optical zone in order to spare tissue for higher ablations on thinner cor- neas. An aberrometer that is paired to the laser gives the added advan- tage of decreasing data entry error and treating higher order aberra- tions," she said. Dr. Dell believes the new aberrometer device on the iDesign system (Abbott Medical Optics) is the "premier, top shelf type of tech- nology that is available for dedicated refractive surgeons" as it essentially incorporates an aberrometer with a built-in topographer unit, as well as a pupillometer and an autorefractor. But the iDesign system's features make it almost ideal for the "occa- sional user who just wants to touch up a premium IOL case," he said. "The technology is a more robust version of what physicians have been using for wavefront-guided treatments for years." What technique to use If the manifest refraction best cor- rected image quality is "super crisp" and patients have a "normal tear film and cornea (including thick- ness)," then either PRK or LASIK is an effective choice, Dr. Thompson said. "But if we know that tear film abnormalities may be an issue, and we treat that tear film and the refrac- tion is still not crisp and topography is normal, I start to think about occult anterior basement membrane dystrophy as the cause of surface irregularity leading to reduced image For surgeons with only an occasional need for an excimer laser, here are some of the major bells and whistles to consider H igh-volume refractive prac- tices are well versed in the features today's excimer lasers provide—and how those features are provid- ing even better patient outcomes. But for the premium lens cataract surgeon who may be performing infrequent corrections for residual refractive errors, what are the most important features to consider? Excluding obvious parameters such as physical footprint, EyeWorld asked several leading refractive surgeons for their opinions. First and foremost, they said, remember that most often the enhancements are very minor and most platforms will be sufficient. "I usually prefer standard treat- ments because these are low correc- tions, and since there is an IOL in the eye, the refraction and typical parameters such as axial length and corneal curvature have been decou- pled," said John Berdahl, MD, in practice at Vance Thompson Vision, Sioux Falls, S.D., who uses both the VISX (Abbott Medical Optics, Abbott Park, Ill.) and WaveLight (Alcon, Fort Worth, Texas) for these purpos- es. "I think the biggest key is a good stable refraction, and I have grown to favor LASIK over PRK because I think this older population has a tendency to have more epithelial irregularities that affect the refrac- tion and can become unmasked with PRK." When evaluating laser systems, Vance Thompson, MD, director of refractive surgery, Vance Thompson Vision, said it's important to know the data—what percentage is within ±0.25 D and ±0.5 D for low correc- tions, what percentage results in 20/20. When considering buying a laser, "make sure the laser is FDA-ap- proved for the enhancement label, or it's an off-label use," he said. For Steven Dell, MD, founder of Dell Laser Consultants, Austin, Tex- as, the occasional refractive surgeon may not need to master LASIK. "They can very simply do PRK, which is a whole lot simpler to learn, and because of the low or relatively low prescriptions that are being treated, nomogram adjust- ments are not particularly import- ant," Dr. Dell said. "Let's say you're treating 0.75 D of residual myopia, and you miss by 10%. That's a clini- cally irrelevant number. If you were treating –7 D and were off by 10%, that's visually significant." However, any surgeon who is implanting premium IOLs needs to have some sort of laser vision cor- rection solution available "or they're not going to get any significant trac- tion in their practices," he said. Keeping "everything simple" is the key to enhancing these patients, said Uday Devgan, MD, in pri- vate practice, Devgan Eye Surgery, clinical professor, UCLA, and chief of ophthalmology, Olive View-UCLA Medical Center. Among his top 3 pearls: wait 3 months for the refraction to stabilize; the patient Excimer lasers and enhancement procedures Monovision continued from page 50 "Presbyopes have not always been accepting of this type of cor- rection," Dr. Pallikaris explained. "However, two-thirds of presbyopes can accept monovision [LASIK] today. Overall, anyone presenting with presbyopia can be corrected by a refractive procedure 85% of the time." EW References 1. Reilly CD, Lee WB, Alvarenga L, et al. Surgical monovision and monovision reversal in LASIK. Cornea. 2006;25:136–138. 2. Johannsdottir KR, Stelmach LB. Monovision: a review of the scientific literature. Optom Vis Sci. 2001;78:646–651. 3. Garcia-Gonzalez M, Teus MA, Hernandez- Verdejo JL. Visual outcomes of LASIK-induced monovision in myopic patients with presby- opia. Am J Ophthalmol. 2010;150:381–386. 4. Alarcón A, Anera RG, Villa C, Jiménez del Barco L, Gutierrez R. Visual quality after mono- vision correction by laser in situ keratomileu- sis in presbyopic patients. J Cataract Refract Surg. 2011;37:1629–1635. Editors' note: Dr. Pallikaris has financial interests with Presbia (Irvine, Calif.). Contact information Pallikaris: pallikar@med.uoc.gr When coupled with the new iDesign high resolution aberrometer, true wavefront-guided treatments with the VISX S4 laser are producing great results with laser vision correction, according to Dr. Dell. Source: Steven Dell, MD Device focus

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