Refractive
Spring 2025

by Liz Hillman
Editorial Co-Director

Patients who opt to have an advanced-technology IOL (whether it be toric or presbyopia correcting) tend to have higher expectations for their postop vision, and as such, most surgeons proficient with these lenses are prepared to provide enhancements via laser vision correction, IOL rotation, or IOL exchange, when needed.

So while some level of enhancements are expected with refractive cataract surgery, what is an “acceptable” enhancement rate?

Lance Kugler, MD, first pointed out that we have to agree upon what the criteria ought to be for enhancements.

“If we can agree that achieving a spherical equivalent within 0.50 D, with 0.50 D or less of cylinder, is the goal for multifocal IOL patients, the data is quite clear,” Dr. Kugler said. “Most studies that have looked at IOL calculation accuracy have determined that modern formulas can deliver around 80% within 0.50 D of the intended target. The best datasets published are between 90–92%. That means that in the best possible scenario, the best we can hope for is an 8–10% enhancement rate. Informal surveys of experienced refractive/IOL surgeons suggest that 10–12% enhancement rate is typical in practices that are tracking these outcomes closely.”

John Berdahl, MD, said the range is from 2.5–12.5%.

“Like anything in medicine, there’s judgment on risk versus benefit. But in our practice, we are very willing to take someone from good to great with even a small correction,” he said.

Enhancement stigma?

Dr. Kugler added that he doesn’t think it’s possible to have a less than 10% enhancement rate, per published data.

“Certainly a surgeon could decide to have a lower enhancement rate by choosing to not offer enhancements, but that simply means that 8–10% of their patents are not seeing as well as they should be and are likely unhappy,” he said.

When asked whether there might be a “stigma” around doing enhancements that could have some surgeons avoiding them, Dr. Kugler said yes. “I think surgeons often think that an enhancement means failure. Patients may think that, too, if they are not properly counseled. In our practice, we tell every patient that they should expect to require an enhancement and that it is a normal part of the process. That way, when needed, they do not interpret it to be a failure,” he said.

“Our job is not to protect our ego; our job is to get the best possible outcome for the patient,” Dr. Berdahl said. He said that enhancement rates vary from surgeon to surgeon based on their personal judgment, technology available to them, experience with refractive surgery, and use of modern formulas and cataract surgery techniques.

However, predicting the future is easy, but being right is hard, he continued. “There are some patients who don’t fall into the exact parameters for IOL calculations or even aberrometry. And there are some patients who don’t tolerate a new optical system that includes multifocality or extended depth of focus,” Dr. Berdahl said. “Our job is to take the patient where they’re at and get them to the best place possible.

“Now, surgeons are humans, too, so oftentimes we think of an IOL exchange or a LASIK enhancement as a failure or that we missed. It only becomes a failure when you quit trying to solve the problem,” he said. “My message to patients if they have an eye that’s not pristine before surgery is that they have a higher chance of needing an IOL exchange, and if they’re willing to take the risk of a trifocal IOL in exchange for the vision they want for the rest of their lives, I’m willing to take that risk alongside them as long as we both think that it’s not a failure if we need to take that lens out. Similarly, I tell patients that 1 out of 10 or less patients will need a laser enhancement after surgery. We include that in the price because we know that it’s going to happen to some patients because our predictive capability isn’t perfect.”

Enhancement considerations

Dr. Kugler begins to consider an enhancement for the patient when there is treatable refractive error that is decreasing visual quality.

“If the patient is happy with their less-than-optimal vision, sometimes they choose to forego the additional step, but we make it very clear that we recommend it in order to maximize vision quality,” Dr. Kugler said.

As with any refractive surgery, ocular surface management before and after is critical, Dr. Kugler continued. Treating the ocular surface can decrease the need for enhancement or at least changes the measurements.

Dr. Berdahl said he knows an enhancement is on the table if there is 1 D of cylinder or 0.5 D or more of a refractive miss postop. Smaller refractive misses are more of a judgment call. In those latter cases, he relies on a few things.

“One is the topography, two is epithelial mapping, three is an assessment of dryness, and four is the OCT. The final common pathway is a pair of temporary glasses; if that patient wears a pair of temporary glasses with that prescription and they say, ‘This is how I want to see,’ I know that a laser enhancement is the move,” he said. When it comes to the epithelium, Dr. Berdahl said one needs to make sure that it’s uniform, clear, and not EBMD, even subclinical.

Other pearls for enhancements that Dr. Berdahl offered are to intervene early with a temporary pair of glasses for unhappy patients.

“If a patient’s unhappy at 1 week and they have refractive error, I give a temporary pair of glasses very early for two reasons. One is an unhappy patient is often just a scared patient, and if you can show them that they can see well, they’ll go from being scared to understanding that we’ve got a solution for them. Number two, I know that they don’t have PCO yet. So if they develop early PCO, I know that if the glasses fixed their vision, it’s not the PCO that came later and I can YAG them and do their laser enhancement.”

When he determines an enhancement is needed, Dr. Berdahl said research has found LASIK to be more predictable than PRK.¹ “The most likely reason for this is that irregular epithelium of older patients is common. So when you do a PRK, you wipe off that epithelium and it grows back in a different, smoother configuration, which is nice, however, it’s less predictable for the refraction, so we usually do LASIK, if we can,” he said.

Forward thinking

When offering advanced-technology IOLs, surgeons must have an enhancement strategy, according to Dr. Kugler. This means not only considering broader access to enhancement tools but also each individual patient’s possible future scenarios.

“If a future enhancement is not possible due to abnormal corneas or other comorbidity, a multifocal IOL or IOL requiring a high precision outcome should be avoided,” Dr. Kugler said. “The Light Adjustable Lens [LAL, RxSight] is often a good option in these patients. This is particularly true of post-refractive patients who are difficult to enhance after IOL procedures.”

If surgeons do not have access to LASIK as a post-refractive cataract surgery enhancement tool, Dr. Kugler suggested partnering with a local LASIK surgeon for these cases as a potential strategy. He again mentioned the LAL as a possible strategy instead of LASIK.

“Some surgeons use IOL exchange as an enhancement tool, but doing so does not produce the same level of precision in outcomes, particularly for low amounts of astigmatism,” Dr. Kugler added.

Overall, Dr. Kugler thinks that enhancements are among the biggest barriers to adoption of advanced-technology IOLs in cataract practices.

“Lack of access to enhancements, or lack of planning for enhancements, is one of the biggest if not the biggest factor to the low adoption rate of premium IOLs,” he said.

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About the physicians

John Berdahl, MD
Vance Thompson Vision
Sioux Falls, South Dakota

Lance Kugler, MD
Kugler Vision
Omaha, Nebraska

Reference

1. Rohlf D, et al. Outcomes of LASIK vs PRK enhancement in eyes with prior cataract surgery. J Cataract Refract Surg. 2023;49:62–68.

Relevant disclosures

Berdahl: Alcon, Bausch + Lomb, Johnson & Johnson Vision, Zeiss
Kugler: Johnson & Johnson Vision, Zeiss

Contact

Berdahl: john.berdahl@vancethompsonvision.com
Kugler: lkugler@kuglervision.com