EyeWorld Asia-Pacific March 2018 Issue

A phakic IOL causing a cataract years af- ter insertion Source: Uday Devgan, MD Phakic IOLs - from page 37 38 EWAP REFRACTIVE March 2018 “Phakic IOLs are capable of correct- ing high ametropias that conven- tional laser refractive surgery can’t reach,” he said. “For those high am- etropias that may still be corrected with laser refractive surgery, phakic IOLs do not induce corneal aberra- tions, leaving better quality of vision and the cornea intact. Importantly, the patient will not be limited for fu- ture laser corneal surgery treatments if the ametropia progresses in the future. This is particularly important for young high myopes.” When these patients become presbyopic later in life and go on to develop cataracts, they will still have virgin corneas and their natural crystalline lens, so all of the available treatment options will still be availa- ble to them, including corneal inlays and presbyopia-correcting IOLs. Dr. Parkhurst noted that not all patients are candidates for phakic IOLs. For example, patients must have adequate anterior chamber depth and enough room in front of the eye to fit the phakic IOL safely. “Different surgeons have different cut-offs. The Visian ICL [STAAR Surgical, Monrovia, California] label recommends a minimum anterior chamber depth of 3.0 mm. A lot of surgeons that I know are comfort- able going down to 2.9 or 2.8, but ultimately there is a minimum depth at which there’s just not adequate space,” he said. Additionally, surgeons must wait until children achieve ocu- lar maturity or ocular adulthood before correcting their myopia. “Most people reach ocular maturity somewhere between the ages of 18 and 21. It’s quite rare to do any refractive surgery before that age, although it’s not unheard of,” Dr. Parkhurst said. “There have been reports of using phakic IOLs in chil- dren as amblyopia therapy. But rou- tinely, for the correction of myopia, we’re waiting until they’re adults on the low end. On the upper end of age, the labeling for the ICL goes up to age 45. I think most people start leaning away from a phakic IOL ap- proach and toward other options at about age 50 for a couple of reasons. Today we do not have multifocal or extended depth of focus phakic IOLs. Once you get into full-fledged presbyopia, there are other options available that can address both myopia and presbyopia.” Phakic IOL implantation re- quires careful surgical technique. “It is critical to monitor IOP in the early postoperative period because retained viscoelastic might in- duce acute glaucoma, which may cause residual Urrets-Zavalia or an anterior subcapsular cataract,” Dr. Alió del Barrio said. “The surgeon should always monitor the patient in the clinic for 60 to 90 minutes after surgery, and the patient should not leave until the IOP is properly controlled.” Deciding not to incorporate phakic IOLs into practice Some surgeons think that the disad- vantages outweigh the advantages and have chosen not to offer them to patients. “I used to implant many of them because they filled an unmet need for my patients, however, I have stopped implanting them now because it is an intraocu- lar procedure and there can be endothelial cell loss and the devel- opment of cataracts,” 2,3 said Uday Devgan, MD, Los Angeles. “Addi- tionally, I think the rate of cataract formation is much more than we originally thought. My one golden rule of surgery is to give patients the same high level of care that I would want to receive. If my own child was a –12 or a –15, I would not implant a phakic IOL. I would tell him or her to wear contacts. It’s just not good enough for me at this time, but it is an informed consent decision for the patient.” Dr. Devgan noted that there were anterior chamber phakic IOLs in Europe that never came to the U.S. that were associated with problems. “Additionally, some other promising phakic IOLs that were in development are gone,” he said. “Al- con [Fort Worth, Texas] had the Ca- chet anterior chamber phakic IOL that was made with the AcrySof ma- terial and underwent FDA trials but did not receive approval. Part of the difficulty is that companies must invest a huge amount of money for the few people who are candidates. Getting a phakic IOL through FDA trials costs tens of millions of dol- lars at a minimum, and I think only a small percentage of candidates who want refractive surgery are bet- ter candidates for phakic IOLs than they are for LASIK.” The future Dr. Parkhurst thinks that phakic IOLs will have an expanded role in the future. “We are anxiously awaiting the approval of a toric ICL,” he said. “Right now, we only have myopic, spherical phakic IOLs. Once there’s a toric, more patients will be eligible because many of our patients have at least some refrac- tive cylinder. Additionally, making a very minor design modification by putting a central fenestration in the ICL has been shown to decrease risks of IOP elevation around the time of surgery and has even re- duced the unlikely event of cataract formation because there’s better bathing of the anterior crystalline lens with aqueous through this central fenestration. I know many surgeons who have implemented this in other countries and have seen their ICL volumes go up sig- nificantly with the advent of that minor change.” EWAP References 1. Chuck RS, et al. Refractive management/ intervention preferred practice pattern devel- opment process and participants. AAO. 2017. https://www.aao.org/Assets/96621d35- ff5f.../refractive-ppp-in-press-10-24-17-pdf 2. Guber I, Mouvet V, et al. Clinical outcomes and cataract formation rates in eyes 10 years after posterior phakic lens implantation for myopia. JAMA Ophthalmol. 2016;134(5):487– 94. 3. Moya T, Javaloy J, et al. Implantable collamer lens for myopia: Assessment 12 years after implantation. J Refract Surg. 2015;31(8):548–56. Editors’ note: Dr. Parkhurst has finan- cial interests with STAAR Surgical. Drs. Alió del Barrio and Devgan have no financial interests related to their comments. Contact information Alio: Jorge_alio@hotmail.com Devgan: devgan@gmail.com Parkhurst: gparkhurst@parkhurstnuvi- sion.com