37 EyeWorld Asia-Pacific | December 2024 “It is important for the ophthalmologist to identify patients who prioritize visual quality over spectacle independence as we decide upon an IOL to implant,” he said. “Each surgeon should develop a way to tease out that information, either by way of questionnaires or during face-to-face consultation. If you suspect the patient to be ‘type A,’ you should plan to do your best to address preexisting HOAs and possibly avoid presbyopia-correcting diffractive IOL implantation.” HOAs informing IOL selection Dr. Armstrong said he’ll tailor his IOL selection to the patient’s corneal HOAs, avoiding presbyopia-correcting IOLs that use diffractive optics if the abnormal HOAs cannot be addressed preoperatively. “Monofocal IOLs are a safer option because they are less affected by HOAs,” he said. “Pinhole IOLs can partially neutralize the visual impact of corneal HOAs. … Normal spherical aberration of the cornea is about 0.3 μm for a 6-mm pupil size, thus most common IOLs have a negative spherical aberration of about –0.2 μm (matching that of the natural crystalline lens). However, we should consider picking an IOL that shifts the spherical abberations of the eye closer to zero, in patients with abnormal levels of spherical aberration (>±0.5 μm). We have an array of IOLs, some of which have negative, neutral, and positive spherical aberration, and we should do our best to utilize the right IOL to achieve the best possible visual outcome.” Dr. Rocha offered a similar perspective, discussing the different enhanced monofocal IOL options that offer customization for patients with HOAs. REFRACTIVE SURGERY “You can even customize with the new generation of monofocal IOLs or enhanced monofocal IOLs; we have a lot of options. Some are aberration-free. Some come with positive or negative spherical aberration. I think the rule is you should not end up with more than 0.4 μm of spherical aberration after implanting that IOL,” she said. Dr. Gatinel said to focus on corneal aberrations in this case because any preop aberrations from the lens will be removed in cataract surgery. “In this situation, you need to direct the corneal wavefront,” he said, adding that research should be conducted to understand the interactions between the IOL options and different corneal aberrations to “cherry pick the one that is most relevant for the patient.” HOAs and refractive surgery If a patient is seeking refractive surgery, does not yet need cataract surgery, and has HOAs, Dr. Gatinel said he’ll first tell patients to stop rubbing their eyes. Once it seems like they’ve understood the importance of this and do not progress with the habit, he finds wavefront-guided PRK to be the best option to improve the corneal shape. If you’re confident they won’t rub their eyes in the future, and the corneal topography shows moderate abnormalities, LASIK could be an option. He added that he would avoid premium lens implantation after lenticular extraction for patients with elevated and/or symptomatic HOAs. Dr. Rocha, in a presentation, offered several pearls for managing HOAs in the setting of corneal refractive surgery. 1. Make sure maps are reproducible and verify long-term refractive stability. 2. Compare the wavefront refraction with the manifest and cycloplegic refractions and the topographic maps with wavefront aberrations.
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