September 2018

COVER FEATURE

Products that could change how you practice
What to know about the Light Adjustable Lens


by Ellen Stodola EyeWorld Senior Staff Writer/Digital Editor


First patient implanted in the FDA PMA trial after all treatment has been done. The patient is a 70-year-old male with UCDVA 20/12 and UCNVA J2.
Source: Kevin Waltz, MD

The lens is FDA approved but not yet commercially available in the U.S.

Though FDA approved, the Light Adjustable Lens (LAL, RxSight, Aliso Viejo, California) is not yet currently available in the U.S. Robert Maloney, MD, Los Angeles, John Doane, MD, Leawood, Kansas, David F. Chang, MD, Los Altos, California, and Kevin Waltz, MD, Indianapolis, discussed their experience with the lens in clinical trial, how it works, and for what corrections it has approval.

LAL in the clinical trial

Dr. Maloney said that with this lens, the patient has routine cataract surgery, and several weeks postop, instead of prescribing spectacles, the surgeon exposes the LAL to a precise pattern of light that changes the shape of the lens to correct the residual refractive error.
“The clinical trial results were remarkable,” he said. “The amazing thing for me about the clinical trial was patients having their blurry vision clear up after the light treatment.” He added that “it was like magic to them.” The hardest part of the clinical trial, Dr. Maloney said, was to tell the patients that they couldn’t have the LAL in the second eye, since it was a unilateral eye study.
“The concept is the lens can change its three-dimensional shape after being exposed to light,” Dr. Doane said. “Particles or monomers can easily migrate within the lens and do so when exposed to ultraviolet light.” He added that to flatten the center of the lens to treat myopia, you would expose the light to the periphery of the lens and the monomers would migrate there, and subsequently thicken the periphery of the implant and flatten the center. “The exact opposite occurs if we want to treat hyperopia,” he said. “We expose the center of the lens, the monomers migrate to the center and thicken the center of the lens, and increase the radius of curvature, resolving the hyperopic refractive error.” Variations on this then can be done for astigmatism or any shape desired.
Dr. Doane described his experience in the clinical trial as “very straightforward.”
“The surgery is done exactly like we do with a standard monofocal lens implant,” he said. “The difference occurs postoperatively in that at 2–3 weeks postoperatively, we refract the patient.” If the patient’s refraction is not ideal the doctor can place them behind the light delivery system of the RxSight device and expose them to around 90 seconds of light to “adjust” their refractive state to the desired target. After this, Dr. Doane said the patient should be rechecked in 4–5 days. “If the patient likes the unaided vision, we can ‘lock in’ this refraction,” he said. “If not, we can make a second adjustment, wait 4–5 days, and lock in their preferred endpoint.”
After the IOL implantation, and until about 3 days after the final light exposure, the patient wears specific UV range blocking glasses, Dr. Doane said. “Other than that, the drops and postop are identical to typical cataract surgery.”
During the trial, Dr. Chang implanted the first 16 LALs in the U.S. as a Phase 2 investigator. “The adjustment and lock-in procedures are quite straightforward. Like a YAG capsulotomy, they are performed in the office with a slit lamp delivery system using a contact lens to focus the treatment,” he said.
Dr. Chang said that refractive accuracy has improved thanks to advances such as intraoperative aberrometry, improved biometry, and better calculation methods, but these are all still different methods for IOL power prediction. “They improve the mean but don’t eliminate the standard deviation, especially in challenging eyes post-refractive surgery, or with unusual keratometry or axial lengths,” he said.
Dr. Chang added that the EUREQUO study reported refractive results from more than 280,000 patients from 100 clinics. This “real world” data set reported that 27% of eyes failed to land within 0.5 D of the spherical refractive target.1
“Although I currently employ corneal topography and wavefront aberrometry, swept-source OCT biometry, multiple advanced
formulae, intraoperative aberrometry, and digital intraoperative axis localization, an ophthalmologist right out of residency should achieve better refractive outcomes with an adjustable IOL than I currently do using all of these technologies for my toric monofocals,” he said.

Adjusting implant with light versus PRK or LASIK

Dr. Doane said after 22 years in practice, he would rather adjust the IOL than the cornea. “Involving the cornea adds another layer of healing and tissue biology that we can avoid when we deal with the lens and light adjustment,” he said. “The older the patient, the more important this concept is to understand.”
Dr. Maloney said he thinks patients would much rather have the implant adjusted than have corneal adjustment with PRK or LASIK. “We think of refractive surgery as no big deal,” he said. “No matter how we explain it, patients think of LASIK and PRK as having their eye sliced and zapped.”
Dr. Waltz, who implanted the first lens in the FDA PMA trial, said that either option would work, but he thinks the LAL can give better results than PRK or LASIK. He added that patients also have variability in how their epithelium and stroma heal. There’s not much variability in how the LAL heals, he said, so you don’t get the surprises that you get with other technologies. “I think if you knew you had to do it, most everyone who could afford it would do the light adjustable lens,” he said. “The cost would be a negative, but the quality will be better with the light adjustable.”

Accuracy of the LAL

Dr. Maloney said that 92% of LAL eyes are within 0.5 D of target. “The best number for every other lens is about 70%,” he said. “That doesn’t include astigmatism correction, which is better with the [LAL] also.”
Dr. Doane added that this is the “most accurate refractive procedure I have been involved in” with respect to outcomes with +/–0.25 and +/–0.5 D. He added that since such a high percentage of eyes were +/–0.5 D, they looked at +/–0.25 D, which is one level more accurate than corneal laser vision correction.
Dr. Waltz said that he has found the LAL to be “shockingly accurate.” He added that the trial included patients with only certain amounts of astigmatism.
He said the results of the trial were the best trial results he has seen. “In a typical U.S. trial, you’ll have about 40–50% of the patients be 20/20 uncorrected,” he said. “In this trial, which was more difficult because you had to be astigmatic, LAL eyes achieved 20/20 or better uncorrected vision in more than 70% of eyes, which was approximately two times the rate of the control group. Additionally, approximately a third of the LAL patients were 20/16 or better.”
Since distance was so good, it improved the intermediate and near as well, Dr. Waltz said.
He added that the process for the LAL is a bit more complex, requiring multiple light treatments before it’s locked in. This technology also comes with an extra fee for the work that is involved, which Dr. Waltz estimated could be $5,000–8,000 per eye.

Correction permanence

Dr. Maloney said that after the adjustment of the lens is completed, it is locked in to ensure that the lens doesn’t change in the future.
“Humans are living biological tissue, so living tissue can change,” Dr. Doane said. “From everything we can tell with long-term results, in our centers and long-term data outside the U.S., the IOL remains stable.”
He added that the cornea can change its astigmatism over time, and this will likely be what could change and alter the patients’ unaided vision. “My contention is that if the cornea doesn’t change then the result will be stable long term,” he said.

Approved corrections

Currently in the U.S., the LAL is approved for myopia, hyperopia, and astigmatism, alone or in combination, up to 2 D, Dr. Maloney said.
For the future, the LAL can do as many corrections as there are patterns of light.
At present, Dr. Doane said that +/–2 D of sphere and 0.75–2 D of astigmatism are approved in the U.S. Outside the U.S., the treatments can be done to 3 D of sphere (plus or minus) and 3 D of astigmatism.
Looking ahead, he said that any pattern could be possible. “My guess is that an extended depth of focus or multifocal pattern to resolve presbyopic complaints would be the next order of interest from surgeons and the company,” he said.
The FDA approval was for postoperative adjustment of sphere and cylinder, Dr. Chang said. “This means that the [LAL] should become the ideal toric IOL for low to moderate astigmatism in my opinion,” he said. “Although we get excellent results currently, we still must estimate posterior corneal astigmatism and surgically induced astigmatism.” He added that low power toric IOLs are not available in the U.S. A study by Inoue et al. showed that 28% of the net mean toric IOL axis misalignment at 1 year was from surgical misalignment.2 Dr. Chang added that even when using digital surgical alignment, a study from his practice showed that postop rotation of more than 5 degrees occurs between 8–18% of the time, depending on the IOL model.3 Correcting the astigmatism after several weeks postoperatively circumvents all of these issues, he said.
Dr. Chang thinks this new technology will help change the patient experience. “We will all welcome the improvement in refractive accuracy,” he said. “However, the biggest benefit will be the ability for patients to ‘try’ different pseudophakic refractive options postoperatively as a better way to decide what they want.”
Having to decide whether they want better uncorrected distance, mid-range, or near vision preoperatively is confusing and stressful for patients, he said. Without an IOL already in their eye, how can patients understand the difference between being plano or –1.00? Or if they want to read without glasses, how can they decide between wanting –2.00 or –3.00? “Adjustable IOLs will allow patients to use trial lenses or even trial soft contact lenses to make this decision postoperatively,” Dr. Chang said. “We all know that mini-monovision is extremely popular for contact lens wearing presbyopes, largely because the anisometropia can be adjusted and can be reversed if it is not tolerated.” He added that adjustable IOLs will give patients the ability to try out different amounts of pseudophakic anisometropia before the cataract surgeon delivers this result with confidence. “For patients, so much of the stressful preoperative decision making will shift to the postoperative period, when an optometrist can explain and demonstrate the options instead of the cataract surgeon,” he said. “I think that patients, their referring optometrist, and their cataract surgeon will all be happier with this arrangement.”

References

1. Lundstrom M, et al. Risk factors for refractive error after cataract surgery: analysis of 282,811 cataract extractions reported to the European Registry of Quality Outcomes for Cataract and Refractive Surgery. J Cataract Refract Surg. 2018:44;447–452.
2. Inoue Y, et al. Axis misalignment of toric intraocular lens: placement error and postoperative rotation. Ophthalmology. 2017;124:1424–1425.
3. Lee BS, Chang DF. Comparison of the rotational stability of two toric intraocular lenses in 1273 consecutive eyes. Ophthalmology. March 2018. Epub ahead of print.

Editors’ note: Dr. Chang and Dr. Maloney have financial interests with RxSight. Dr. Waltz and Dr. Doane have no financial interests related to their comments.

Contact information

Chang
: dceye@earthlink.net
Doane: jdoane@discovervision.com
Maloney: info@maloneyvision.com
Waltz: kwaltz56@gmail.com

What to know about the Light Adjustable Lens What to know about the Light Adjustable Lens
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