Eyeworld

57 EW FEATURE June 2016 • Controversies in ophthalmology the orientation of a toric IOL would undoubtedly be off after a second transplant, he said. Laser versus manual LRIs When performing LRIs, surgeons have the option of making the inci- sions manually or using the femto- second laser, and there are pros and cons to each method, according to the physicians. The femtosecond laser provides incomparable accuracy when it comes to depth and placement of incisions, but experienced surgeons get very good results with manual incisions as well. "Diamond blades can give equally good results in the hands of an expert surgeon," Dr. Devgan said. One advantage of the femtosec- ond laser is it can measure pachym- etry in real time and adjust the treatment so it is at exactly the right depth, Dr. Devgan said. In addition, laser treatments are initially closed and can be opened in a step-wise manner to titrate the astigmatic ef- fect. Dr. Devgan's surgery center has both the LenSx (Alcon, Fort Worth, Texas) and Catalys (Abbott Medical Optics, Abbott Park, Illinois) femto- second laser systems. "I use a Victus laser [Bausch + Lomb, Bridgewater, New Jersey], which gives me real-time OCT, and that allows me to keep my incisions When are LRIs best? LRIs are generally best for correct- ing low amounts of astigmatism— around 1.5 D or less, according to the doctors. "For 1.5 D or more of corneal astigmatism, toric IOLs will provide a more accurate and more stable re- fractive correction," Dr. Devgan said. However, if a patient has an affordability issue with a toric lens, Dr. Whitman will treat up to 2 D of astigmatism with LRIs, but only if it is symmetric. "If there is irregularity in the topography, I lean toward toric lenses and certainly if there is more than 1.5 D of astigmatism," he said. Both methods have strong safe- ty records, but are slightly different in efficacy, according to Dr. Devgan. While toric IOLs are effective across a full range of corrections—from 1 to 4 D—the efficacy of LRIs is more variable, he said. LRIs work well for lower degrees of correction, such as 0.5 to 1.25 D of corneal astigmatism, but become less predictable and less accurate at higher corrections. "Attempting to do a 3 or 4 D AK/LRI is not likely to give good results and may even lead to de- stabilization and irregularity of the cornea," Dr. Devgan said. Dr. Devgan thinks toric lenses work best for corneas with perfect- ly symmetric, regular astigmatism because the toric has perfectly sym- metric optics. In eyes with asymmet- ric astigmatism—seen as a somewhat lopsided bowtie on topography—the advantage of LRIs is surgeons can do a more aggressive treatment at the meridian with the most astigmatism and less treatment on the side with less astigmatism, he said. Corneal elasticity changes with age, so LRIs are not as effective in younger patients, Dr. Devgan added. He avoids treating patients under 50 with LRIs, he said. Corneal pachymetry must also be taken into account; thicker corneas will require deeper cuts. "The best AK/LRI nomograms are the ones that are both age- and pachymetry-adjusted," he said. Dr. Hamilton treats more than 1 D of astigmatism with toric IOLs, but if a patient wants a multifocal IOL, he'll use an LRI and treat up to 1.5 D of astigmatism. If a patient has more than 2 D of astigmatism, he discourages multifocal use and prefers toric monovision for specta- cle independence, he said. He also uses this option for post-refractive surgery patients. Dry eye is another consideration when choosing which option to use, as is prior corneal surgery, according to Dr. Hamilton. If a patient has had a corneal transplant, and the surgeon is worried the patient may need a second graft in the future, an LRI makes more sense because Poll size: 148 " Patients will be seeing the world through our surgeries every waking moment for the rest of their lives. My goal is to give the very best to the patient and to place cost as a secondary consideration. " –Uday Devgan, MD continued on page 58

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