EyeWorld Asia-Pacific December 2019 Issue

FEATURE 22 EWAP DECEMBER 2019 intact zonules and appropriately sized capsulotomy openings relative to optic size (1 mm less than optic size ideally),” she said. “I avoid placing three-piece IOLs in the sulcus without iris suture wÝ>Ì >Ã Ìi " V> ÌÞ«V>Þ move over time. If there is no sulcus support or capsule then I will choose an intrascleral or Gore- /iÝ ÃÕÌÕÀi wÝ>Ì ÌiVµÕi°» Time to exchange? The physicians noted potential indications for IOL exchange including: decentration without bag support, damage to the IOL, patient dissatisfaction with vision or residual refractive error that cannot be corrected with cornea refractive surgery or lens repositioning, iris optic V>«ÌÕÀi] ÀÃ V>w}] `ÃV>Ì into the vitreous cavity, and other conditions such as UGH syndrome. “The level of IOL subluxation as well as the amount of IOL movement during exam is important in deciding when to intervene,” Dr. Schockman said. Exchange is reasonable if the vision is affected or if the IOL looks like it is about to fall posteriorly. “A fallen IOL risks ÀiÌ> `>>}i] y>>Ì] and long-term vision loss,” she said. While it is impossible to predict, a slit lamp exam can provide a good sense of the «ÃÃLÌÞ v Ì VVÕÀÀ}° º w` it helpful to have the patient lay their head back to see how the IOL will behave once they are supine in the operating room. During this maneuver, some IOLs rotate posteriorly enough that I am able to properly plan for intraoperative help from my retinal colleagues.” Vitreous in the anterior chamber should also be noted. Dr. Garg highlighted the need for the surgeon to be prepared and to discuss the situation with the patient in these cases. “When to exchange an IOL requires a thorough discussion with the patient about Ìi ÀÃ] LiiwÌÃ] >ÌiÀ>ÌÛiÃ] and complications,” he said. Recalculating powers Calculating IOL powers is particularly challenging during IOL exchange. Patients should be counseled that our ability to hit our refractive targets are limited with secondary IOL placement. “IOL exchange power determination can be challenging and all patients are consented to understand that we cannot reliably predict the exact refractive target,” Dr. Fram said. In her experience, the Holladay 1 formula helps obtain the best results. “Additionally, one should attempt to understand where the optic will sit in the eye. If it is sulcus placement with some capsule support, then the surgeon should adjust the IOL calculation and back off the power depending on the power of the IOL (see www.doctor-hill. V®° v Ìi wÝ>Ì ÌiVµÕi is optic capture, the IOL calculation should be adjusted for in-the-bag placement. The ÃViÀ> wÝ>Ì ÌiVµÕiÃ >Ài typically 2.5–3 mm posterior to the limbus depending on the white-to-white and an in-the- bag calculation is appropriate. That being said, having a record of the previous IOL implanted and a current refraction is an excellent starting point. One can then deduce the new power by adjusting the A-constants. In cases of aphakia or bag- ÌL>} iÝV>}i w` Ì>Ì intraoperative aberrometry is helpful to verify lens power. Lastly, the Barrett Rx formula calculator assists with calculating outcomes for IOL exchange and piggyback IOLs based on refraction after cataract surgery. Preoperative and postoperative biometry is necessary for proper entry and completed results.” “Sometimes we have to make an educated guess based on the status of the patient’s fellow eye,” Dr. Garg said. “If, however, the currently implanted IOL power is known and a proper refraction can be done, one can estimate the new IOL power. There are also online calculators that can help physicians estimate the power needed.” “I usually have the patient back monthly for several months to ensure a stable refraction,” Dr. Schockman said. “Once the refraction with the current IOL is known, the 3:2 rule can be used to determine what new IOL power is needed. “Refractive predictability Üi ÃViÀ> wÝ>Ì} > " >vÌiÀ removing a dislocated IOL is less reliable since the effective lens position is so variable,” Dr. Schockman continued. “I typically choose an IOL power using the traditional methods or base it off a patient’s prior IOL power. In such cases, it is important to discuss with the patient that residual refractive error is likely.” EWAP Reference 1. Siegel MJ, Condon GP. Single suture ÀÃÌV>«ÃÕÀiÝÃ wÝ>Ì vÀ ÌiL>} intraocular lens subluxation. J Cataract Refractive Surg. 2015;41:2347–52. Editors’ note: Dr. Fram practices at Advanced Vision Care, Los Angeles, is clinical instructor at the Stein Eye Institute, UCLA, Los Angeles, and FGENCTGF PQ TGNGXCPV ƂPCPEKCN KPVGTGUVU Dr. Garg is vice chair of clinical ophthalmology and medical director at Gavin Herbert Eye Institute, University of California, Irvine, California, and FGENCTGF PQ TGNGXCPV ƂPCPEKCN KPVGTGUVU Dr. Hoffman is clinical associate professor of ophthalmology at Casey Eye Institute, Oregon Health and Science University, Eugene, Oregon, and FGENCTGF PQ TGNGXCPV ƂPCPEKCN KPVGTGUVU Dr. Khandelwal is assistant professor of ophthalmology at Baylor College of Medicine, Cullen Eye Institute, Houston, and has a relevant interest in Carl Zeiss Meditec. Dr. Schockman practices at the Cincinnati Eye Institute, is volunteer instructor at the University of Cincinnati, Cincinnati, and declared no relevant ƂPCPEKCN KPVGTGUVU 4GVTKGXGF JCRVKEU YKVJ JGCVGF ƃCPIG QP VJG GPFU Source (all): Nicole Fram, MD