EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
Issue link: https://digital.eyeworld.org/i/78719
66 EW FEATURE February 2011IOLs February 2012 Phakic lenses today by Enette Ngoei EyeWorld Contributing Editor AT A GLANCE • Studies comparing refractive sur- gery results of high myopes who underwent PRK, LASIK, or phakic IOL implantation showed that the quality of vision achieved with pha- kic IOLs is better than the quality of vision achieved with LASIK or PRK • One advantage of the Visian ICL is it's invisible to the naked eye. It sits behind the iris and does not reflect light. On the downside, it requires an iridectomy (or two) and causes cataract formation in a certain number of eyes • Other potential side effects with the phakic lenses are inflammation and intraocular pressure changes, but those are all treatable with drops • These phakic IOLs have long-term data and can be considered safe for long-term use. That does not mean they work in every patient forever EyeWorld gets an update on the advantages and long-term safety of phakic lenses H igh myopes who desire spectacle independence but aren't good candi- dates for LASIK or pho- torefractive keratectomy (PRK) shouldn't feel left out in the cold. Phakic IOL technology contin- ues to advance, and the IOLs avail- able today can be good options. Mastering continued from page 65 Best tools As far as tools are concerned, Dr. Ahmed said microforceps, microscis- sors and micrograspers are "ab- solutely essential" to manipulate the lenses in these complex cases. Dr. Kymionis said a sulcus im- plantation and iris-sutured IOL only require standard cataract instru- ments. "In cases of iris-sutured IOLs, the McCannel sutures are neces- sary," he said. "When performing the glued IOL, 20- or 23-gauge reti- nal forceps are necessary to manipu- late and externalize the IOL haptics. Generally, surgeons have to use in- Example of the Verisyse phakic IOL Example of the Verisyse phakic IOL Source: Sonia H. Yoo, M.D. According to Sonia H. Yoo, M.D., associate professor of clinical ophthalmology, Bascom Palmer Eye Institute, Miller School of Medicine, University of Miami, many studies have shown that there is a high quality of vision with phakic IOLs for moderate and high myopes. Studies comparing refractive surgery results of high myopes who underwent PRK, LASIK, or phakic IOL implantation showed that the quality of vision achieved with pha- kic IOLs is better than the quality of vision achieved with LASIK or PRK, Dr. Yoo said. Allon Barsam, M.D., Moorfields Eye Hospital, London, agreed. "In patients who are highly myopic, def- initely with more than 12 D of my- opia, probably with more than 10 D, and possibly with more than 8 D, the evidence suggests that their quality of vision is better with these lenses than with LASIK," he said. "That's because we're not changing the shape of the cornea, inducing a lot of aberration. With the phakic IOLs, we're simply im- planting the lens inside of the eye," Dr. Yoo explained. Another potential advantage of phakic IOLs is that it's not uncom- mon for high myopes who have a phakic IOL placed to have an im- provement in their best corrected visual acuity because of the magnifi- cation effect of having the IOL in the eye, Dr. Yoo added. "I personally have had patients who had phakic IOLs [implanted] whose uncorrected vision is better than their best corrected vision pre- op, which you can imagine is some- thing that makes the patients very excited. That's not usually some- thing we see with LASIK or PRK," she said. FDA-approved lenses The two phakic IOLs that are ap- proved in the United States are the Visian Implantable Collamer Lens (STAAR Surgical, Monrovia, Calif.) and the Verisyse (Abbott Medical Optics, AMO, Santa Ana, Calif.), Dr. Yoo said. A number of other lenses, including the AcrySof Cachet phakic IOL (Alcon, Fort Worth, Texas) and the Visian Toric ICL (STAAR Surgi- cal), are awaiting FDA approval. The main difference between the two approved lenses is that the Verisyse is an iris-fixated phakic IOL, which clips on to the iris, and the Visian ICL sits in the posterior chamber, behind the pupil, Dr. Yoo explained. She uses both the Verisyse and the Visian lenses. The advantage of the Visian ICL, Dr. Yoo said, is that it's a foldable lens so surgeons can get it through a small, clear corneal incision. Wound healing is fast and relatively little astigmatism is in- duced. continued on page 68 struments and techniques that they are familiar and comfortable with because this ensures better surgical outcomes, especially when deal- ing with complicated cases." A pre-op workup is essential be- fore starting a known dislocation case, said Dr. MacDonald. "I like to get a copy of the oper- ative report to know if there were any intraoperative complications and also to make sure the patient was seeing well post-operatively and to know what the refraction was," she said. "What's really important during the workup is to make sure we do a nice anterior and posterior segment exam, looking very closely at the endothelial cell count to make sure that we have a healthy count and that there wasn't exces- sive cell loss during the first surgery. It's important to have a very frank discussion with the patient about the risks and benefits of the surgery. My consent is fairly broad to in- clude different options because we sometimes can't determine what the best course is until we're in the op- erating room." Dr. Hoffman advised surgeons to lay patients back when looking at their lens position. "That's the position they're going to be in when you operate on them," he said. "If you think the lens is coming loose, you need to rush." EW Editors' note: Dr. Ahmed has financial interests with Abbott Medical Optics (Santa Ana, Calif.). Drs. Hoffman, Kymionis, and MacDonald have no fi- nancial interests related to this article. Contact information Ahmed: 416-625 3937, ike.ahmed@utoronto.ca Hoffman: 541-687-2110, rshoffman@finemd.com Kymionis: +30 2810 371800, kymionis@med.uoc.gr MacDonald: 978-538-4442, susan.m.macdonald@lahey.org