Surgeons optimize this light-adjustable lens postoperatively using low-intensity UV light.

The RxSight Light Adjustable Lens (LAL) is the world’s first adjustable IOL that allows for office-based optimization of vision after implantation.

“The LAL was developed to help overcome the limitations of cataract surgery prediction methods,” says Eric Weinberg, chief commercial officer at RxSight in Aliso Viejo, Calif. “Even with today’s technologies, only about six out of 10 patients achieve their targeted vision without glasses, and even fewer achieve excellent vision at all distances,” he explains, citing a 2018 Swedish study by Farhoudi, Behndig, Montan et al. “The LAL delivers LASIK-like outcomes in cataract surgery, where 92% of patients are within +/- 0.50 D.”

Working with a Nobel Prize-winning chemistry professor at the California Institute of Technology, RxSight developed the core technology that enables a physician to postoperatively change the optical power of an IOL using a non-surgical, office-based low-intensity UV light dose when true refractive errors are known.

“Patients receiving the LAL end up with optimal uncorrected visual acuity,” says John Vukich, MD, Milwaukee’s Summit Eye Care of Wisconsin, who implants the lens in patients. “Not only does the lens offer the benefit of freedom from glasses for distance vision, but it also has the distinct advantage of not inducing other optical aberrations that are commonly seen with multifocal lens implants or with extended depth of focal lenses. LAL patients do not complain of glare, halos or spider web dystrophies.”

HOW IT WORKS

The LAL is a three-piece silicone IOL that has additional silicone macromers within the lens. The macromers are mobile and, together with a photoactive component, polymerize as a result of UV light exposure delivered by the light delivery device. In the 1 to 2 days after a light treatment, the diffusion of macromers causes the lens to change shape to either increase or decrease optical power and treat astigmatism.

“The light treatment itself is straightforward for both doctor and patient, taking 30 to 90 seconds to perform, depending upon the desired refractive change,” Mr. Weinberg says. Additional patterns, such as extended depth of focus to treat presbyopia, are currently undergoing an FDA trial.

The LAL is approved for adding or subtracting up to 2.0 D of sphere and up to 2.0 D of astigmatism per light treatment and for up to three refractive light treatments.

When patient and physician are happy with the refractive state of the eye, the LAL is locked-in with a final light treatment to prevent any further refractive change. “At this point, the LAL behaves as a conventional stable silicone IOL,” Mr. Weinberg explains.

In a clinical study, the majority of patients who received the LAL achieved 20/20 or better vision at 6 months without glasses (FDA Summary of Safety and Effectiveness, www.rxsight.com/media/smdgdhqa/rxsight_ssed.pdf ).

Dr. Vukich calls the IOL “revolutionary. It’s the only lens that allows a surgeon to fine tune the power after implantation. For the first time in my career, my patients are routinely achieving 20/15 uncorrected visual acuity.”

Before using the LAL, T. Hunter Newsom, MD, founder and medical director at Newsom Eye in Tampa, Fla., says he had to take measurements and guess what fixed-shape lens would fit a patient’s eye prior to cataract surgery. With RxSight’s LAL, he can change the shape of the lens to fit perfectly.

Adjustments can be made up to three times and are typically done one week apart. The patient directs the lens’ shape by stating what they want, whether it be a better near, intermediate or distance lens.

“After the third adjustment, the patient has the lens that will give them the best potential vision for each eye,” says Dr. Newsom, a principal investigator for the FDA trial of RxSight’s LAL and a consultant for RxSight. “After locking it in, the lens won’t drift and it can’t be changed. I have followed patients for 8 years, and their refractive error didn’t change over time.”

CLINICAL APPLICATIONS

The LAL is most suited to patients who are interested in the best possible visual outcomes and are willing to invest the time to fine tune their vision.

The lens is approved for use on an eye with 0.75 D or more of preoperative keratometric astigmatism. It was recently approved to treat postoperative astigmatism as low as 0.5 D.

The LAL is suitable for anyone who requires cataract surgery and who is suitable for a single lens. The only caveat is that a patient’s pupil must be dilated to at least 6.5 mm. Sometimes patients taking certain medications or supplements can’t achieve that.

“We have to be able to visualize the lens postoperatively to be able to treat it with the UV light source,” Dr. Vukich says.

The LAL should only be used in patients who have good visual potential. “If, for example, they have advanced AMD or glaucoma, the lens may not be ideal for them,” Dr. Newsom says. “Another limiting factor is if the patient has corneal herpes simplex or had it in the past, because shining UV light through the cornea could make the herpes virus flare up.”

The lens is also ideal for patients who had LASIK or radial keratotomy surgery. “When you change the cornea’s shape with these procedures, it is difficult for surgeons to estimate what lens power will fit best,” Dr. Newsom says. “These cases have the most demanding patients and a fixed lens gives the least accurate results of all the surgeries I perform. The LAL is ideal because you don’t need to guess the perfect fit before surgery; you adjust the lens to perfection afterward.”

OVERCOMING CHALLENGES

One challenge for surgeons performing premium cataract surgery is discussing options with patients for optimizing their vision.

“Surgeons can’t easily demonstrate different visual outcomes to a patient with cataracts,” Mr. Weinberg says. “The LAL solves this problem since it allows for lens optimization after the cataract is removed and the visual system is clear. If a patient is uncertain of their desired refractive target, it can be adjusted after cataract surgery.”

Dr. Vukich says, “You don’t have to worry about rotation or incision size or any of a number of other things that can make IOL power selection challenging. You no longer have to rely on other instruments. The lens is made to be enhanced with an office-based light source that’s easy to administer.” OM