Eyeworld

EW FEATURE 78 Revisiting astigmatism • October 2018 AT A GLANCE • Ophthalmologists think a low amount of astigmatism can be tolerated in a patient who has a multifocal or EDOF IOL, but they still seek to reduce it as much as possible. • Options for reducing astigmatism include the use of toric presbyopia- correcting IOLs and limbal relaxing incisions. • There are a range of presbyopia- correcting toric IOLs on the U.S. market, and a few new lenses and technologies in the pipeline that could serve these patients as well. by Liz Hillman EyeWorld Senior Staff Writer EyeWorld: How much astigmatism is tolerable with multifocal and EDOF IOLs before it needs to be corrected? Dr. Patterson: If you've got a multi- focal, I think 0.25–0.3 D is all that's ideal. Some patients can tolerate 0.75 D and they do fine. If they have postoperative astigmatism and the patient is satisfied, I won't do anything, but preoperatively I am going to go down as low as I can to try to treat with a multifocal. With an EDOF lens, I think you have a little more give in those patients. The astigmatism seems to be more tolerated due to the nature of the lens and how the lens optics work. You don't have as many astigmatism problems with this, so I have people who have a half diopter or even a diopter with an EDOF lens postoperatively and they are satisfied, especially if it's with-the- rule. It adds a little more near vision for them. Dr. Raviv: The low-add multifocal IOLs perform best when astigma- tism is minimized to less than 0.5 D. EDOF IOLs have an increased tolerance for residual astigmatism in my experience, nevertheless, I still want to reduce it significantly. Accounting for the lifelong against-the-rule (ATR) shift that will occur in most patients, 1 I generally target about 0.35 D of with-the-rule (WTR) residual cylinder for someone in their 50s or 60s and less for older patients. Dr. Lindstrom: For WTR and ATR, even 0.25 D astigmatism in any axis degrades the image, but the reason- able target is 0.50 D or less. Residual ATR is the worst. EyeWorld: Are LRIs/AKs acceptable to perform with multifocal or EDOF IOLs? Dr. Patterson: I use an LRI on every patient who doesn't qualify for a toric. If the astigmatism is too low for a toric, I'll use an LRI. If the astigmatism is too low for an LRI, I'll shift and make my main incision wound on the axis of that. Experts share thoughts on aspects of astigmatism with presbyopia-correcting IOLs B eing a refractive cataract surgeon means correcting patients' distance vision at the time of cataract surgery, but also often addressing their presbyopia and astigmatic issues as well. "I correct every patient who has astigmatism in a premium lens cases," said Michael Patterson, DO, Eye Centers of Tennessee, Crossville, Tennessee. "If they're going to get premium technologies, they deserve premium astigmatism technology." There are nuances, however, to addressing astigmatism with presbyopia-correcting IOLs. How much astigmatism could be left without correction with a multifocal or extended depth of focus (EDOF) lens? When would you use a toric vs. a limbal relaxing incision? Are there eyes in which you would not implant a multifocal or EDOF lens based on the patient's astigmatism? Dr. Patterson, Tal Raviv, MD, Eye Center of New York, New York, and Richard Lindstrom, MD, Minnesota Eye Consultants, Min- neapolis, shared their thoughts on these and other questions involving astigmatism and presbyopia-correct- ing IOLs. Astigmatism and presbyopia-correcting IOLs A patient with keratoconus would not be a good candidate for premium IOL technology. continued on page 80 I make sure I'm dialed in as close as possible. Dr. Raviv: Yes, the lowest cylinder toric power is 1.5, which treats about 1 D of cylinder on the cornea. Accounting for posterior corneal astigmatism and future ATR drift, I typically will employ femto LRIs for WTR cylinder below 1.5 D or for ATR below 0.4 D. I also peek at the refractive cylinder, especially in a patient over 70; significant ATR cyl- inder in their spectacles/refraction indicates a more significant amount of posterior corneal astigmatism, and generally a higher power toric will be indicated. Dr. Lindstrom: Yes, but I prefer to use a toric IOL or for small amounts of astigmatism on-axis incisions. LRI and AK have poor long-term stabili- ty and induced higher order aber- rations. If needed, a PRK or LASIK works well for residual astigmatism. EyeWorld: What presbyopia-cor- recting toric IOLs are available and at what range? What has been your experience with them? Dr. Patterson: Currently, I use the Tecnis Symfony toric (Johnson & Johnson Vision, Santa Ana, Califor- nia), the AcrySof ReSTOR lens (Al- con, Fort Worth, Texas), Crystalens (Bausch + Lomb, Bridgewater, New Jersey), and Trulign toric (Bausch + Lomb). At this point I use every one on the market at the routine. I am going to use a toric in every patient who qualifies, who de- sires to pay for it. But after you get past that, how do you know what lens? If a patient has macular dis- ease, epiretinal membrane, a small set of drusen, I tend to tell them you don't need a multifocal lens, you either need a Symfony or a Crys- talens. If that patient says I can't handle any side effects, the purest vision they're going to get is with the Crystalens, but they won't get as much reading vision. If the patient says, "I want a little more reading," and they've got a small amount of microaneurysms in the macula from diabetes, I'm not opposed to putting in a Symfony lens in those patients. … If a patient desires close reading vision, I'm not going to use an EDOF or an accommodating lens, I'm going to use a multifocal lens. Dr. Raviv: Today, in the United States, the ReSTOR ACTIVEFOCUS toric, Tecnis Symfony toric, and Trulign toric are available. The cylinder powers available with the toric multifocal IOL/EDOF IOLs are 1.5–3.75 D at the IOL plane, treating up to approximately 2.5 D of astig- matism at the corneal plane. The Trulign toric ranges from 1.25–2.75 D at the IOL plane. Due to the increased incidence of ATR with aging, it is common to

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