Would you use a multifocal lens in an eye with an irregular cornea?
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Consider EDOF or LAL instead
My decision-making on which lens to choose depends on the irregularity I see in the cornea.
The first thing I want to do is make sure the irregularity is not due to dry eye. I treat the ocular surface and make sure it is pristine before moving forward. I see a lot of patients with prior LASIK who had decentered ablations or patients with prior RK. All the aberrations experienced visually by the patient in these complex corneas can be compounded by a multifocal lens in addition to a reduction in contrast.
If the patient has an unusual topography due to corneal scars, keratoconus or previous RK or significant higher-order aberrations, I would be hesitant to use a multifocal lens. When considering a multifocal IOL, I want to give the patient the best chance of maximizing the full potential of their lens, and that largely excludes this group.
Depending on the exact corneal abnormality, my next thought is to implant an extended depth of focus (EDOF) lens. Typically, I pick a non-diffractive optic EDOF IOL such as Vivity (Alcon) as I have found it to be a forgiving IOL, but Symfony OptiBlue (Johnson & Johnson Vision) could be another option that could work as well.
This is a case-by-case decision process; however, I tend to lean on the Light Adjustable Lens (LAL, RxSight) in many of these patients. While a monofocal lens is a reliable option in these cases, if the patient is correctable with glasses or in the phoropter with their irregular cornea, then a customizable approach enabled by the Light Adjustable Lens might be an excellent option. Although not yet available in the U.S., the IC-8 IOL (AcuFocus) will likely be a good choice in these irregular corneas as well.
J. Morgan Micheletti, MD, is an ophthalmologist at Berkeley Eye Center in Texas.
Be cautious
If I see any kind of irregular corneal shape, it is definitely something I want to investigate further.
If there is no dry eye and the cornea is truly irregular, such as ectasia or keratoconus, I would certainly be cautious about implanting a multifocal lens. Sometimes, these patients already have a multifocal cornea. They have higher-order aberrations that, when combined with another multifocal optic, can reduce the clarity and quality of vision.
These patients are going into surgery hoping to be spectacle free or at least less dependent on spectacles than they were before. That combination of irregular cornea and multifocal lens could make it a lot harder to achieve that goal.
In these cases, you could use a monofocal lens, but the Light Adjustable Lens (RxSight) or an extended depth of focus lens could also be interesting options. No matter what we do, we need to be proactive and cautious when evaluating the patient. An irregular cornea can mean a lot of things, so it is not easy to make a blanket statement about which lens will work best. Always repeat measurements to rule out dry eye, and have a good discussion with the patient about their options.
Jennifer M. Loh, MD, is an OSN Technology Board Member.
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