Eyeworld

EW FEATURE 58 Refractive corrections • March 2019 challenges, especially at first. Here are some tips that seasoned sur- geons shared to make ICL use more seamless. 1. Practice alignment with the astigmatism. "The toric ICL re- quires a slightly different mindset than a toric IOL because the latter is correcting only the corneal astigma- tism whereas the ICL is treating the refractive astigmatism," Dr. Kugler said. "Though the majority of refrac- tive astigmatism arises from the cor- nea, the alignment of the ICL may be slightly different than the axis of cylinder seen on topography." Dr. Mertens marks the horizon- tal axis of the cornea in a supine position so the toric ICL can be aligned accordingly to rule out cy- clotorsion errors when the patient is lying on the operation table. 2 2. Size appropriately. "Proper mea- surements are critical to selecting the right size of the Visian ICL," Dr. Dougherty said. He has a published nomogram based on sulcus-to-sul- cus measurement to properly size the lens. 3 "There are four sizes to choose from, and using ultrasound biomicroscopy [UBM], my sizing is more accurate than any other technique available," he said. He also still uses the Online Calculation and Ordering System from STAAR Surgical for spherical and astigmatic power calculation. Dr. Parkhurst also uses UBM technology to measure sizing. "The UBM has been an important tool to get the sizing right," he said. 3. Stay aware of potential sizing mishaps. Sizing of the ICL is the biggest challenge of the lens, ac- cording to Dr. Parkhurst, noting that a too big lens could lead to IOP ris- es, pupillary block, or angle closure. "In the first 24 hours, the surgeon needs to have their cell phone on and if the patient has pain, nausea, or a headache, they should call immediately. This usually indicates the ICL was oversized and that the angle is closed," he said. If the ICL is too small and not sufficiently in the sulcus, the ICL is at risk of rotation. "I tell my patients it's like Goldi- locks. The sizing needs to be just right," Dr. Parkhurst said. 4. Consider vertex distance of the refraction. This may not be im- portant with lower myopes, but it can make a difference with higher myopes, Dr. Parkhurst said. "That subtle 1 or 2 mm of distance can throw things off significantly," he said. "We often employ a contact lens overrefraction, so let's say someone is –12 D, we'd put in a –10 lens and refract to –2 from there. That minimizes the effect of vertex to get the refraction right." 5. Eliminate dry eye in advance. This can help exclude refractive errors, said Dr. Mertens, who also uses anterior and posterior corneal topography to reduce the chance of surgical surprises. 6. Educate patients in advance on visual quality. Patients with kera- toconus or subclinical keratoconus may still have some astigmatism, Dr. Kugler said. If these patients are used to wearing scleral or gas per- meable contact lenses, they may be dissatisfied with the toric ICL visual quality. Let patients know about this potential outcome, and tell them that they may not be able to wear these lenses after implantation. One additional pearl In addition to the surgical learning curve, Dr. Dougherty shared one more suggestion to maximize your use of the toric ICL. Beef up your marketing. There's obviously a lot more aware- ness about LASIK, Dr. Dougherty said, but when consumers know someone with the ICL, they are more eager to book the day of con- sultations than those hearing about the technology for the first time, he explained. To boost awareness, his practice markets the Visian ICL on its website, through social media, to their optometrist network, and di- rectly to consumers through public relations efforts. EW References 1. Parkhurst GD. A prospective comparison of phakic collamer lenses and wavefront-op- timized laser-assisted in situ keratomileusis for correction of myopia. Clin Ophthalmol. 2016;10:1209–15. 2. Mertens E. Posterior Chamber Toric Implantable Collamer Lenses – Literature Review. Astigmatism – Optics, Physiology and Management. 2012:181–192. 3. Dougherty PJ, et al. Improving accuracy of phakic intraocular lens sizing using high-fre- quency ultrasound biomicroscopy. J Cataract Refract Surg. 2011;37:13–8. Editors' note: Drs. Dougherty, Mertens, and Parkhurst have financial interests with STAAR Surgical. Dr. Kugler has no financial interests related to his comments. Contact information Dougherty: flapzap@gmail.com Kugler: lkugler@kuglervision.com Mertens: E.Mertens@medipolis.be Parkhurst: gparkhurst@parkhurstnuvision.com letting patients know that among the four physicians at his practice, three of the spouses—including Dr. Parkhurst's wife—have had ICLs for years and are happy with their vision. Patients with certain pathology that may limit other corrections— for instance, a thin cornea, severe dry eye, or stable keratoconus—can benefit from the toric ICL, Dr. Dougherty said. Surgical challenges and tips Just like with any new technology, use of the ICL can present with Careful marking of the horizontal axis in a supine position is of the utmost importance. Source: Erik Mertens, MD The toric marking lines on the toric ICL are useful to correct the astigmatism in the right axis. Source: Erik Mertens, MD Making continued from page 56

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