FEB 2014

EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.

Issue link: https://digital.eyeworld.org/i/274531

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Page 72 of 114

EW SECONDARY FEATURE 70 February 2011 Toric IOLs February 2014 Ophthalmic surgeons share pearls, perspectives T here's a starter question to ask if your patient has a toric IOL that is not at the r ight position postopera- tively: Is the patient happy with his/her vision? "If their vision is 20/25 or per- haps even 20/40, I advise leaving it alone. There's no need to reposition their toric lens if they are happy," said Terry Kim, MD, professor of ophthalmology, Duke University Eye C enter, Durham, N.C. "Many patients are happy with better, though not perfect, refractive outcomes," said Michael Y. Wong, MD, Princeton Eye Group, Prince- ton, N.J., and instructor, Rutgers Medical School, New Brunswick, N.J. However, if the patient is unhappy, there are a few choices to consider. First, consider the possible cause of his/her dissatisfaction. "If the patient is not happy, you have to go through a systematic process of eval- uation," Dr. Kim said. "Other things could be limiting vision, such as dry eye or a retinal issue." Factors that help fixate a toric IOL include rotational friction of the haptics at the capsular bag equator, the tackiness of the acrylic material, the adhesiveness of fibronectin be- tween the IOL and the bag and the square edge of the implant, Dr. Wong said. Anything interfering with these factors are possible causes of lens rotation. Dr. Horn finds that certain lenses tend to return to the same position repeatedly. "The lens seems to have a home. It's not just twirling around. Often, it will return to its previously maligned position," he said. It's also possible that the lens was never placed where you had originally planned to place it, due to common inaccuracies during preop planning for lens alignment. If the patient would benefit from a minor or moderate change, Brad Black, MD, founder, Eye Associates, Jeffersonville, Ind., will then discuss a procedure to reposition the implant. He uses the website www.astigmatismfix.com which requires the current refraction and axis of the implant. [Editors' note: The website was designed by John Berdahl, MD, and David Hardten, MD, to determine if a previously placed toric IOL is properly aligned.] The website then gives the optimal axis of the implant, which may or may not be the original in- tended axis. It will also predict the residual astigmatism after rotation allowing one to decide whether ex- changing the implant or correcting the residual astigmatism with laser vision correction might be neces- sary. In situations where a "fix" is absolutely needed, Dr. Black said he is quick to discuss rotating the lens with surgery. "I see no reason to wait, especially if the patient is unhappy and there is significant rotation of the IOL." After reopening the original incision, he will use a cohesive viscoelastic material like DisCoVisc (Alcon, Fort Worth Texas), which he finds is viscous enough to separate the anterior capsule from the posterior capsule but is still easy enough to remove once the implant is repositioned. He will then remark the new axis as determined by the Astigmatism Fix website. "We'll place marks at the limbus based on where the IOL is currently located," he said. "If the implant axis is at 80 and we need it at 92, we simply mark 12 degrees from where the lens is. When rotating the lens, remember it is important to rotate it at least 180 degrees to make sure the footplates are freed up from any 'tunnels' that surround the haptics within the capsular bag. If the IOL is only rotated a few degrees, there's a chance it'll rotate back to where it was before." Some surgeons, like Jeff Horn, MD, Vision for Life, Nashville, Tenn., recommend the use of capsu- lar tension rings (CTRs) when repo- sitioning the lens. The CTR seems to help keep the lens in place. "I think they are effective because they apply an equal equatorial force around the equatorial diameter," he said. "If you have to reposition the lens more than once, an argument can be made to put in a CTR first and then reposition the lens," Dr. Black said. There are some surgeons who support reverse capture of the optic when the lens repeatedly rotates out of position, Dr. Black said. This situ- ation seems to be more common in highly myopic eyes. Is timing everything? If a patient's toric IOL has rotated, how soon should you fix it? Dr. Kim will consider the p atient's vision at one month post- operatively and then decide if any a ction is needed. He does not recom- mend rotating the toric lens too early in the immediate postop period because other factors such as corneal edema may affect visual and refractive results, he said. Although there are many sur- geons who will fix the problem as soon as possible to make patients h appy, other surgeons believe in waiting a little longer. "If a repositioning is the chosen treatment, it's better to wait a month or two," Dr. Wong said. "You want a confident and stable refrac- tion, and it is helpful that the capsu- lar bag has had a chance to shrink a bit. There is no rush to get in, as it is surprising how easy it is to viscodis- sect the capsular bag, freeing the IOL." "If you fix it quickly and the lens rotates again, patients are more unhappy than they were before," Dr. Horn said. "Managing patients' expectations goes a long way." Although Dr. Wong prefers to go back in within three months, he said surgeons can safely go in up to one year postoperatively. If the patient has a strong fibrotic band adherent to the anterior capsulotomy edge, Dr. Wong recommends starting the dissection with a stream of balanced salt solution bevel down and placed between the optic and anterior capsule. "Once a radial channel is dissected, viscoelastic material can follow." EW Editors' note: Drs. Black and Horn have financial interests with Alcon. Dr. Kim has financial interests with Alcon, Bausch + Lomb (Rochester, N.Y.), and other ophthalmic companies. Dr. Wong has no financial interests related to this article. Contact information Black: drbradblack@aol.com Horn: Jeff.Horn@bestvisionforlife.com Kim: terry.kim@duke.edu Wong: mwong2020@gmail.com by Vanessa Caceres EyeWorld Contributing Writer Off axis? Fixing a toric IOL that's malpositioned A real-world example from the toric calculator at astigmatismfix.com Source: John Berdahl, MD 69-71 2nd Feature_EW February 2014-DL2_Layout 1 1/30/14 10:52 AM Page 70

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