EyeWorld Asia-Pacific September 2016 Issue

49 EWAP CATARACT/IOL September 2016 There’s residual astigmatism postop—now what? Experts discuss how to deal with astigmatic surprises as well as prevent them in the first place with toric IOL patients I f patients are willing to pay for a premium toric lens in the hope of achieving a refractive cataract surgery that will leave them glasses-free, then the surgeon has to be ready to “get people into the end zone of their visual goals,” said John Berdahl, MD, Sioux Falls, South Dakota. At the postoperative stage, this means not stopping at “good enough”—not settling for a 20/25–3 outcome, for example, if your patient is unhappy, Dr. Berdahl said. “They put their trust in you to do everything that you can to deliver on that outcome so be prepared to take it all the way until they are satisfied,” he said. The first thing to do when assessing toric IOL patients postop is to simply ask them if they’re happy with their vision, Dr. Berdahl said, noting they’d complain of a lack of clarity, blurriness, or double vision if there was residual astigmatism. “If their postoperative refraction has residual cylinder and they’re not satisfied with their vision, then you need to take further steps to figure out how to get them to a place that’s consistent with their visual goals,” Dr. Berdahl said. From there, Dr. Berdahl said he looks at the placement of the toric lens, checking on its axis placement. He uses the slit beam on his slit lamp, lining it up with the marks on the lens. Then he’ll pull the slit lamp back and uses an app, like Axis Assistant, to determine the axis of the lens. “Once you know the axis of the lens, the power of the lens, and the refraction, you can go to a website like astigmatismfix.com, enter the information, and it will [determine] if rotating the lens would be helpful by calculating an expected refraction after rotation,” he said. If the refraction is satisfactory—both spherical equivalent and cylinder—Dr. Berdahl said he would rotate the lens. But if the spherical equivalent is not acceptable or if there is too much residual cylinder, then he would consider a lens exchange or laser vision correction. Jeremy Kieval, MD , Lexington, Massachusetts, conducts his postop assessments 1 week after surgery, also using Axis Assistant to determine the IOL’s axis of alignment. If there is any unanticipated residual by Liz Hillman EyeWorld Staff Writer Mark the current and ideal axis for targeted rotation. Source: John Berdahl, MD continued on page 51 astigmatism, he’ll first repeat all of the measurements of the patient’s corneal astigmatism, verifying that the appropriate surgical plan was created and carried out in the operating room. He’ll also look for conditions that could be causing it, such as corneal edema, dry eye syndrome, or anterior basement membrane dystrophy. Once these factors are ruled out, he looks at IOL malpositioning or rotation. “Once I can determine a stable refractive cylinder, anywhere between 1–3 months postoperatively, I use the Berdahl– Hardten toric IOL calculator (astigmatismfix.com ) to determine the ideal axis of alignment with the patient. More often than not, I can rotate or exchange the IOL to reduce residual cylinder,” Dr. Kieval said, noting that the ideal time to take someone back to the OR for a fix is between 4 weeks and 6 months postop. David Hardten, MD , Minneapolis, said he would go back into the OR 1 or 2 months postop for a patient needing rotation or lens exchange. “I typically use topical anesthesia and will use paracenteses to add viscoelastic material to provide anterior chamber stability. Then, using either the viscoelastic cannula, a 30-gauge needle, or a viscocanalostomy cannula, I’ll dissect the anterior capsule from the IOL and free the haptics of the IOL,” Dr. Hardten said. “I will rotate the IOL into the correct orientation with a Sinskey hook. I often add a capsular tension ring as I feel that it may reduce rotation of the implant again. The meridian for rotation is based not on preoperative markings in the rotation of an already implanted IOL, but on the difference between current position and the new desired position, so it is important to mark where the implant is and where you want to leave the implant. I then remove the viscoelastic with bimanual irrigation aspiration to reduce any effect of a larger wound on corneal astigmatism.” Similarly, Dr. Berdahl said lens rotation is easier than the first time around because you don’t have to take cyclorotation into account. It’s as simple as rotating the IOL to its new location based on the results provided by a tool like astigmatismfix.com. Fixing residual astigmatism is all well and good, but what about efforts to prevent it in the first place? The two previous “YES Connect” columns addressed the pre- and intraoperative steps that should be taken to correct astigmatism at the time of cataract surgery [See “Preoperative