The advent of presbyopia-correcting IOLS (PC-IOLs) has enabled surgeons to deliver a substantial lifestyle improvement to patients over standard monofocals, and thus attain whole new levels of patient satisfaction. So, as an owner or physician in an ASC, you need to understand PC-IOLs. According to Robert J. Weinstock, MD, director of cataract and refractive surgery and medical director at Eye Institute of West Florida, Tampa Bay, Florida, offering them is becoming the standard of care in modern ophthalmic practices.
“All successful practices have implemented tools into their cataract practices to help them free their patients of glasses after cataract surgery,” he says.
In this article, we’ll offer specifics on 3 major categories of premium PC-IOLs: full range of vision (FROV); extended depth of focus (EDOF); and the Light Adjustable Lens (LAL, RxSight). Let’s start with the FROV. (We will not address monofocal or monofocal toric IOLs.)
FROVs
Full range of vision IOLs provide spectacle independence by splitting light into different focal points, explains John A. Hovanesian, MD, Harvard Eye Associates, Laguna Hills, California. The goal is to provide optimal near, intermediate and distance vision. (This category includes trifocal IOLs and lenses that elongate the distribution of focus across a wide defocus curve.)
The drawback to splitting light in this way, as you likely are aware, is that it can lead to side effects, including night vision disturbances such as glare and halo. However, in the last year and a half, “we've had some new entrants into the market that have allowed us to offer the full range of vision presbyopia-correcting IOLs with less risk for glare,” according to William B. Trattler, MD, a refractive, corneal and cataract eye surgeon at the Center for Excellence in Eye Care, Miami. “That's really opened up the floodgates to a lot of patients that may have been on the fence because the glare profile is just so much better.”
We are in, Dr. Trattler notes, a “golden era for the full range of vision intraocular lenses.”
He points out that the Alcon Clareon PanOptix IOL can provide a full range of vision with relatively low risk of glare. He adds that the Johnson & Johnson Tecnis Odyssey and Bausch + Lomb enVista Envy IOLs have similar full range of vision options and an even lower risk of glare.
“We've been able to offer patients presbyopia-correcting IOLs with less fear that they're going to be unhappy due to night-vision disturbances,” says Dr. Trattler.
The Odyssey offers a wider landing field that provides good range of vision even if the IOL was a half diopter away from zero either way, according to Jeffrey Whitman, MD, chief of surgery, Key-Whitman Eye Center, Dallas/Fort Worth. An advantage of the Envy, he notes, is that it can decrease glare, halo and starburst due to decreased step height of the optics.
“ENVY has the enviable statistic that it can correct under 1 diopter of astigmatism and over 4 diopters at the cornea,” says Dr. Whitman. “With ENVY, we have a lens that can correct small amounts of astigmatism, along with doing good distance, intermediate and close up.”
Another lens is the Lenstec ClearView 3, notes Dr. Whitman. Unlike other IOLs, it uses a non-concentric ring refractive design, which can eliminate glare, halo and starburst.
Patient Selection
Candidates for a FROV IOL should have a healthy tear film, cornea, retina and optic nerve, says Vance Thompson, MD, founder, and refractive and cataract surgeon at Vance Thompson Vision in Sioux Falls, South Dakota. FROV patients need healthy eyes, agrees Dr. Hovanesian, because “any time you're splitting light, you’re sacrificing some form of visual quality.”
For instance, a patient with significant uncontrolled dry eye may not do as well with these lenses, notes Dr. Hovanesian. Two-thirds of patients coming in for cataract surgery suffer from some degree of dry eye, he estimates; what’s more, patients with previous refractive surgery or any prior cause of corneal irregularity may also have challenges.
“Also, comorbidities that reduce potential visual acuity (without cataract) to 20/25 or less should make us hesitate to use these lenses that split light. In my practice, only about a third of patients really are great candidates for the trifocals and full range of vision lenses,” he says.
Healing and adaption time are other considerations. “We need patients to understand the first 3 to 6 months are spent optimizing their eye, and the second 3 to 6 months is their brain adapting to their new optical system,” says Dr. Thompson.
EDOF
Although FROV lenses may be the optimal choice for many patients, for some, an extended depth of focus (EDOF) IOL may prove more suitable. An EDOF lens, says Dr. Thompson, typically is designed to provide quality distance and intermediate vision. These lenses provide less reduction in contrast sensitivity, he explains.
“Anything that in an eye or a personality that cannot take the reduction in contrast sensitivity that a trifocal gives, we start to think about EDOF technology,” says Dr. Thompson.
Dr. Hovanesian points out that EDOF lenses have the advantage of being a little more forgiving of residual refractive error as well as various imperfections in the eye. For example, he notes, post-LASIK patients can potentially receive an Alcon Clareon Vivity IOL or a J&J Tecnis Symfony lens.
Other EDOF lenses include the Bausch + Lomb Crystalens and IC-8 Apthera IOL. Dr. Hovanesian notes that while the Crystalens has made a claim to be an accommodating lens, it does not so much accommodate as provide extended depth of focus.
The Apthera would be considered an EDOF lens. With its small aperture, Dr. Hovanesian explains, it reliably provides a range of vision and corrects astigmatism regardless of the axis.
Dr. Trattler says he no longer uses EDOF lenses because of the lower glare profile of the newer FROV lenses. “With these options for our patients, we really don't need the EDOF. The EDOF lens still has some glare profile, but they don't give that full range of vision. Some patients feel frustrated they're not getting as good near vision as they can hope for and paid for.”
Light Adjusting
Among PC-IOLs, the RxSight Light Adjustable Lens (LAL) and new LAL+ occupy perhaps a unique position. After implantation, the surgeon can use ultraviolet light treatments to adjust lens power. “It's the only lens on Mother Earth that you can customize to the patient, and that's why it's the world's most accurate lens without even a close second,” says Dr. Thompson.
After implantation and when the patient is stable, a surgeon can use a series of UV light treatments that change the shape of the lens using the firm’s Light Delivery Device. These UV light treatments, Dr. Whitman explains, can be used to correct astigmatism, or move the patient to a more nearsighted or farsighted adjustment.
Specifically, after implantation, Dr. Whitman will leave his LAL patients hyperopic, at roughly plus 75 sphere. In this way, when he moves the patient to zero, he has to add at least a half diopter of plus power. “That takes the confirmation of the lens and increases the depth of field of the lens by at least a half a diopter,” he says. The patient will not only have excellent distance vision but also can see a computer screen quite well because he has increased the depth of focus.
“Generally, they end up being 20/30 at distance, but they'll be probably J2, J1 up close. Together, they usually just love their vision,” according to Dr. Whitman.
Although Dr. Whitman uses the LAL in post-refractive patients, he’ll use the new LAL+ in a virgin eye. The LAL+ has a modified aspheric anterior surface that creates a small continuous increase in central lens power, which is designed to slightly extend the depth of focus, according to RxSight. He has found that he can hit the targets, including extended depth of focus, in roughly half the number of treatments it would take for the original LAL.
Similarly, Dr. Trattler will use the LAL in patients who have had LASIK, RK and some corneal irregularities where hitting the target could be difficult.
“The light adjustable lens offers great quality vision, some extended range of vision, and you can really nail your visual outcome because you adjust the results afterwards,” says Dr. Trattler.
Dr. Trattler will make sure to alert patients to the need to wear UV-blocking glasses during the daytime until light adjustments are complete. In addition, he’ll discuss the need for patience, as vision won’t be optimized for 6 weeks to 3 months. He will also review cost, as the LAL can be one of the most expensive IOL options.
Framing the Discussion
Dr. Hovanesian notes that physicians should be comfortable having a conversation with their patients about premium IOLs and the associated expense. “I tell patients at the beginning of the conversation that I'm going to implant in your eye probably the most important product you'll ever receive, because you're going to spend the rest of your life looking through it. There are advanced technology lenses that are designed to do more for you that cost money that's not covered by insurance. I want to be very clear, I'm not here to sell you anything, but I do want you to understand your choices, so you can make a decision you’ll be happy with.”
He continues, “When you frame the discussion that way, you are not selling anything to the patient. You are just having a planning discussion, just as if you were an optician dispensing glasses, except these glasses are permanent. You're doing your duty as a doctor.” OASC