Eyeworld

EW FEATURE 108 Current and future IOL choices • March 2018 astigmatism than those lenses will correct, I'll either use arcuate inci- sions from a femtosecond laser to treat the astigmatism that's residual or do LASIK/PRK postoperatively," he said. "Most commonly in the U.S., the way that I would handle that would be with a bioptics approach," Dr. Swan said. Toric IOL vs. corneal procedure to correct cylinder "My approach to this is a little different because I have ORA [Alcon] to help guide me with how much astigmatism someone has," Dr. Woodard said. For anyone who has approximately 0.5 D of astigmatism against-the-rule or 0.6 with-the-rule, he will plan to treat astigmatism in some form. Treatment could be with a toric IOL or arcuate incisions with the laser. Dr. Woodard said he plans based on input from several technologies: corneal topography, refraction, and the ORA. Dr. Swan said that the typical rule of thumb is if you have great- er than 0.74 D against-the-rule or greater than 1.25 with-the-rule, it's best to go with a toric. "I also use intraoperative aberrometry to see if it makes more sense to do a toric or limbal relaxing incision," he said. Generally speaking, if it's greater than those values, Dr. Swan is likely to place a toric and less than that, he will use an LRI. Dr. Holland said there is some debate on the efficacy and stabil- ity of astigmatic treatments. The femtosecond arcuate incisions are more accurate and more stable than a diamond knife LRI, but they're not as stable as a toric lens, he said. "You can't predict the tissue response to surgery in each patient's cornea, so you can get undercorrections or overcorrections; that is why toric IOLs have better outcomes when treating any astigmatism that is not minimal," Dr. Holland said. Even with femtosecond arcuate incisions, the toric is more accurate, Dr. Holland said, and he suggested considering femto arcuate incisions for mild astigmatism especially if it is with the rule. When not to implant a toric IOL Dr. Woodard said a patient who has very irregular corneal astigmatism is not a great candidate for a toric IOL. He added that patients who have corneal disease that causes irregular astigmatism are also not good candidates generally. He said to proceed with caution in these patients, like those with post-corne- al transplants, those with epithelial basement membrane dystrophy (EBMD), or those with Salzmann's nodular degeneration. "The biggest thing is to make sure the astigmatism is regular," Dr. Greenwood said. If the patient has irregular astigmatism from anterior basement membrane dystrophy or something similar, he or she wouldn't be a good candidate for a toric lens, he said. Similarly, patients with severe keratoconus, where the astigmatism is not regular, wouldn't be good candidates. Dr. Holland recommends mak- ing sure there is no corneal disease that could be accounting for astig- matism such as Salzmann's nodular degeneration, epithelial basement membrane degeneration, or pteryg- ium. These conditions are unstable and may need to be managed and will result in a change of astigma- tism. Another situation that Dr. Holland cautions about when using a toric IOL is if the patient has some instability of the capsular bag, the lens could rotate. It might not be advised if there is posterior capsular tear and the capsule is unstable. Monovision with a toric IOL Many monovision patients are be- ing treated with toric contact lenses for monovision, Dr. Woodard said, adding that he doesn't make any special concessions for monovision. He did note that for patients doing monovision in one eye, the near eye is usually more tolerant to residual astigmatism than the dis- tance eye. "In the distance eye, I'd want to correct anyone with at least 0.5 to 0.75 D of astigmatism, but for near, that amount is not usually visually significant," he said. The way to approach mono- vision with a toric IOL is similar to monovision in a patient who doesn't have astigmatism, Dr. Greenwood said. You want to make sure you nail the target outcome in the distance eye, and figure out where they want their near point to be. "In most patients, that's some- where between –1.25 and –2.25, depending on what they like to do and what their previous history with monovision has been," he said. Dr. Swan said that if the patient hasn't had monovision before, he's hesitant to do it. He's more likely to use an extended depth of focus or multifocal IOL in those who haven't already tried monovision. Additional points Dr. Greenwood said that as a glau- coma and cornea surgeon, he thinks that toric IOLs are great options for patients with glaucoma or other eye diseases to reduce their astigmatism and still give them good quality out- comes with the monofocal toric. "Toric IOLs are an excellent premium lens option for surgeons," Dr. Woodard said, and can be particularly good in some cases for surgeons who might be hesitant to enter the premium lens arena. These lenses are usually well tolerated and stable within the eye, he said. Dr. Swan mentioned the value of the astigmatismfix.com website. "If you put a toric in and don't get the result you expect, you can look at it to see what you can do with that information," he said. The website has all current toric models and their corneal plane power for all the major U.S. manufacturers, he added. EW Editors' note: Dr. Greenwood, Dr. Woodard, and Dr. Holland have fi- nancial interests with Alcon. Dr. Swan has no financial interests related to his comments. Contact information: Greenwood: michael.greenwood@vancethompsonvision. com Holland: eholland@holprovision.com Swan: russell.swan@vancethompsonvision.com Woodard: lwoodard@omnieyeatlanta.com Using continued from page 107 How are we doing with astigmatism correction? Elizabeth Yeu, MD, discusses overall outcomes for astigmatism correction with cataract surgery and how to fix residual astigmatism after the surgery. EWReplay.org

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