30 EyeWorld Asia-Pacific | September 2024 REFRACTIVE SURGERY This is an example of mid peripheral transillumination defects from a multifocal IOL causing UGH syndrome. The patient underwent IOL exchange with resolution of inflammation. Source: Allison Chen, MD Another scenario, according to Dr. Wang, is when a patient is unhappy with their refractive outcome. This could mean that they ended up more hyperopic or myopic than expected or they wanted to be corrected for distance vision with a monofocal lens but are then unhappy with the loss of near vision. “In these scenarios, I would first offer non-surgical options such as glasses or contact lens correction. If they do not accept that, laser correction would be the next step. However, not all patients are candidates for laser correction, and others may strongly prefer a lens exchange.” Dr. Chen added, “If a patient is very motivated for a trifocal IOL to decrease spectacle dependence, I’ll often first put it in the non-dominant eye to see if they are able to tolerate the potential glare. If they are happy with it, we can do the same for the dominant eye, but if they want less glare in the dominant eye, we can place a monofocal.” When to exchange Dr. Wang said this may depend on whether you’re the primary surgeon or if the patient was referred to you. If you are the primary surgeon or had the patient referred soon after the initial surgery, Dr. Wang said she may be more likely to offer an exchange on the early side. If the problem is a large refractive surprise, you want to perform the exchange sooner rather than later, she said, but if it’s dysphotopsia, she will encourage them to wait at least 3 months. But you have to judge patients individually. If the patient has complaints immediately after surgery, she’s careful not to do YAG capsulotomy, keeping in mind that exchange is a possibility. In cases of UGH syndrome, Dr. Chen will exchange the IOL as quickly as possible to decrease further intraocular inflammation. For vision quality issues and dysphotopsias, she monitors for at least 3–6 months to assess for symptom improvement prior to performing an exchange. “I also carefully evaluate the ocular surface to ensure that it is optimized,” she said. “In cases of refractive surprises, I monitor the patient for at least 3 months to ensure stability of refraction, given it takes time for the IOL to settle into its final effective lens position in the capsular bag.” Dr. Chen also describes to the patient the potential reasons as to why they may be having visual symptoms and addresses other possible etiologies such as surface dryness or irregularities. “Once all else is optimized, we can proceed with the IOL exchange if the IOL itself is the most likely reason for vision problems,” she said. “I also emphasize that certain ‘brains’, rather than the person themselves, possess a strong dislike for specific IOLs.” Techniques Applying an he appropriate technique for IOL exchange will depend on the lens that was placed, Dr. Wang said. It’s important to know what lens is in the eye. Dr. Chen said, “In cases of refractive surprises, if I know the initial IOL that was placed, this 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 the accuracy of the refractive outcome.” Another possible scenario is when a lens has come loose. This technically also requires an exchange as well. You could have a lens that was placed 10–15 years ago and it becomes loose or dislocated for a variety of reasons. If there is a stable capsular bag, the best outcome is to exchange it from within the bag. “As long as they do not have an open capsule, we can do a bag to bag exchange,” Dr. Wang said. “If they have a very small opening in the capsule, you can attempt to perform the bag to bag exchange, but it may be more difficult because the capsule opening often enlarges during surgery,” Dr. Wang further explained. 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 elaborated.
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