EyeWorld Asia-Pacific March 2021 Issue

38 EWAP MAR C H 2021 CORNEA eye surgeon to obtain more reliable measurements to use for IOL calculation and astigmatism planning.” In patients with more severe disease, it may take weeks or months to adequately tune up the ocular surface. To obtain pre-surgical topography, keratometry, and biometry, Dr. Matossian said, adequate tear film stabilization can typically be achieved within 2–3 weeks, assuming the patient adheres to the recommended at-home therapies and/ or agrees to undergo an out-of- pocket, in-office treatment. Lens choices There are a variety of lens options that can be used for dry eye patients. Sometimes the patient makes it easy, Dr. Sheppard said, if they know what they do or don’t want or if they just want the option that will be covered by insurance. “If you have someone with no dry eye, they can benefit from just about any IOL as long as the retinal architecture is intact,” Dr. Sheppard said. “If you have patients with recalcitrant dry eye, I’ll talk them out of a multifocal.” A toric lens makes a lot more sense for these patients, he added. Dr. Pflugfelder agreed that toric lenses are well tolerated and also advised caution when recommending multifocal and EDOF IOLs in patients with tear instability, corneal epitheliopathy, or moderate to severe conjunctivochalasis. “I am a firm believer in providing patients with the best possible vision through lens-based surgery, viewing cataract surgery as a refractive procedure,” Dr. Matossian said. “If possible, why not decrease dependence on spectacles?” She said that 0.5–1 D of astigmatism can be treated with LRIs or femto AIs, while astigmatism greater than 1 D can be treated with toric IOLs. “Astigmatism correction will ensure clearer images at all distances,” she said. Presbyopia correction is ideal for patients who want to have greater independence from their glasses, Dr. Matossian said, adding that trifocal, multifocal, and EDOF IOLs provide nice options for patients to see far, intermediate, and near with little reliance on reading spectacles. However, she did note that macular and retinal health are key to ensure success with these IOLs. For patients with moderate to severe dry eye or for those with significant corneal pathology, Dr. Matossian discourages multifocal or EDOF IOLs. Surface stabilization and accurate pre-surgical measurements are mandatory to nail the refractive target for best outcomes, Dr. Matossian said. “Thereafter, a commitment by the patient to maintain their ocular surface health by adhering to their prescribed daily routines and undergoing their annual or semi-annual in- office procedures is paramount.” Considerations for patients with previous refractive surgery “Previous refractive surgery patients are the great nightmare of the cataract surgeon,” Dr. Sheppard said. The worst of these, he said, are the patients who have had RK because they have “amazing amounts of distortion.” Sometimes, they’re so distorted that you’re not sure where the axis lies, he added. LASIK is the next worst particularly in light of a high incidence of ocular surface disease, Dr. Sheppard said, and PRK is also notorious for causing dry eyes. Even SMILE can cause dry eye but seems to be the least offensive. His strategy gears the timing and intensity of therapy to the underlying conditions. If someone had myopic refractive surgery, their corneal curvatures will change, Dr. Sheppard said. This not only makes it more difficult to come up with precise sphere and cylinder calculations, but it also affects the type of lens you select. Patients lose positive asphericity of the cornea and may become flat or negatively aspheric, and you must choose the type of IOL appropriate for that corneal curvature. Dr. Pflugfelder added that some of these patients have a mild component of keratoneuralgia that can be worsened with cataract surgery. “They can be identified as pain out of proportion to signs,” he said. “Some post-LASIK patients may also have dry eye that should be treated as noted above.” Dr. Sheppard added that toric IOLs can limit the use of LRIs, which further disturb corneal nociceptor architecture despite advances in femtosecond laser cataract surgery. Can cataract surgery aggravate dry eye? Ocular surgery causes an inflammatory insult to the eye leading to exacerbation of pre-existing dry eye disease, Dr. Matossian said. The preservatives in the eye medications prescribed pre- and post-surgery may have a toxic effect on the corneal epithelium. “Typically, three medication categories are used: an antibiotic, an NSAID, and a steroid,” she said. “Each is used with a different frequency over a varying number of days or weeks.” Dr. Matossian added that these medication schedules not only lead to a perceived burden by patients and their caregivers but also are wrought with non-compliance. “Patients either forget to use their drops or inadvertently miss their eye altogether, leading to a less than ideal postoperative course.” Two recently FDA-approved steroids can be used either intracamerally at the conclusion of cataract surgery by placing a tiny spherule of dexamethasone under the iris or inside the capsular bag (Dexycu, EyePoint Pharmaceuticals) or via an intracanalicular dexamethasone-