Eyeworld

SUMMER 2024 | EYEWORLD | 47 R by Ellen Stodola Editorial Co-Director Contact Chen: Allison.Chen@bcm.edu Wang: yvonne.wang.yw752@yale.edu About the physicians Allison Chen, MD Assistant Professor Cornea, Anterior Segment, and Refractive Surgery Department of Ophthalmology Baylor College of Medicine Houston, Texas Yvonne Wang, MD Assistant Professor Department of Ophthalmology and Visual Science Yale School of Medicine New Haven, Connecticut Relevant disclosures Chen: None Wang: None helps me more accurately calculate the power of the IOL that it should be exchanged for. In these situations, sticking with the same type of IOL can increase accuracy of the refractive outcome." Another possible scenario is when a lens has come loose. That is technically an exchange as well. You could have a lens that was placed 10–15 years ago and it becomes loose or dislo- cated for a variety of reasons. If there is a stable capsular bag, the best outcome is to exchange from within the bag to within the bag. As long as they do not have an open capsule, we can do bag to bag, Dr. Wang said. If they have a very small opening in the capsule, you can attempt to do bag to bag, but it may be more difficult because often the capsule opening enlarges a bit during surgery, Dr. Wang said. In such cases, the implanted lens can be placed in the sulcus. However, there are more limitations as to which type of IOLs can be safely placed in the sulcus, so it is important to have the right lens available. "Even if I plan to exchange a lens bag-to-bag, I have a sulcus lens available as a backup in case the bag becomes compromised," she said. If the lens is loose, there is no capsular sup- port, and you need to exchange it out, she said, this can involve taking out the entire lens-bag complex and placing a secondarily fixated IOL (scleral fixated with or without sutures). Depending on the patient and the stability of their capsular anatomy, Dr. Chen will perform either in-the-bag IOL exchanges or explantation and removal of the IOL and capsule (if com- promised) with secondary IOL implantation via either flanged intrascleral haptic fixation (ISHF) or scleral-sutured IOL techniques. If there is a 3-piece lens already in the eye that needs to be repositioned or scleral fixated due to dislocation or UGH syndrome, she will usually first consid- er re-scleral fixating the same IOL to minimize trauma to the corneal endothelium. Tips and tricks Dr. Wang recommended starting off with having a good discussion on expectations and patient goals and taking your time. It's also important to have a surgical plan and share this with the patient. Knowing what type of lens is in the eye is key, Dr. Wang said, especially if it's been a bit of time. The way the lens get fibrosed into the capsule depends on the shape of the lens. It's also important to know how you want to get the lens out of the eye. There are many ways to do this. You can fold and pull it out, cut it completely and pull it out in halves and thirds, or cut it in half, fold, and pull out. You need to make sure you have the right instru- ments to do it, Dr. Wang said, adding that cer- tain lens materials can't be cut, so it's important to know if this is the lens you're dealing with. Dr. Chen also mentioned the differenc- es among types of IOLs. Different IOLs tend to fibrose and adhere to the capsular bag in different places, she said. "With enVista lenses [Bausch + Lomb], the adhesions usually occur in the triangular eyelet at the optic haptic junc- tion. With Tecnis single-piece lenses [Johnson & Johnson Vision], the adhesions are most prominent in the cutout indented area at the optic haptic junction, and with Alcon lens- es, the capsular fibrosis tends to occur at the terminal bulbs of the haptics," she said. "When explanting these IOLs, I use a cohesive OVD on a cannula to ensure full release of the adhesions in these areas and sometimes gently lift the cap- sule while injecting OVD to break the adhesions and to fully open the capsular bag. "Occasionally, haptics are so fibrosed to the bag that they can't be released without compro- mising the zonules. In these cases, to preserve zonular support, I will still open the bag up as much as I can but will amputate the haptics while the IOL is in the bag so that the optic is easier to remove," Dr. Chen said. Dr. Chen said in cases where she preserves and re-scleral fixates the existing 3-piece IOL in the eye, she externalizes the trailing haptic and tests the threading of the trailing haptic into a 30-gauge wide lumen TSK needle prior to tunneling the needle for ISHF to ensure that the intraocular threading will proceed smoothly. "As a precaution, if planning a possible scleral fixation, I obtain permission from the pa- tient's primary care provider or cardiologist to stop aspirin and blood thinners prior to surgery if safe for the patient," she added.

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