FOR DECADES, ophthalmologists have dreamed of replacing a cataract patient’s crystalline lens with a similarly functioning lens that could not only provide distance vision but also address presbyopia by mimicking the ability to see up close with a ciliary body-driven change in optics. Such accommodating intraocular lenses (IOLs) would potentially herald a new era in cataract surgery and presbyopia correction.
While that dream is not yet fully realized, and the technology of accommodating IOLs is still in its infancy, development of these advanced lenses continues. As a surgeon, you’ll want to understand the current state of the art and what the future holds. In this article, you’ll learn about various accommodating lenses in development, the benefits of these lenses, and challenges that must still be overcome. In addition, you’ll gain a deeper perspective on 2 of these lenses by reading about surgeon experience.
A Look at the Lenses
A variety of accommodating IOLs are currently in some stage of development. Here’s a look at some of them.
- FluidVision (PowerVision acquired by Alcon). The FluidVision lens has an acrylic shell filled with silicone oil, allowing it to change shape with accommodation of about 2.00D. As the ciliary muscles constrict with near focus, fluid inside the haptics is pushed into the optic section of the IOL, changing the curvature of the lens. The ciliary muscles relax when focusing at distance, causing the fluid to move back toward the haptics, mimicking a natural lens with no accommodation.1
- Juvene (LensGen). This modular, shape-changing lens has a base lens (BL) and a curvature-changing fluid optic that fits into the BL. More about this lens, including a discussion of recently presented results, can be found later in this article.
- OmniVu (Atia Vision). More about this dual-optic IOL, which features a multiple-lens design, can be found later in this article.
- Opira (ForSight Vision6). This accommodating IOL consists of 2 parts: a static posterior lens and a dynamic anterior surface. Because the IOL’s haptics are fixated in the capsulorrhexis, the surgeon will need to make a proper-sized capsulorrhexis to support the lens implant. The idea behind this system is that it allows more direct interaction between the ciliary body and the lens by not having the IOL positioned in the capsular bag itself. An early clinical trial of 16 patients found the lens achieved uncorrected near vision of 20/25.
Although the Crystalens (Bausch + Lomb) has made a claim of accommodation, it does not so much accommodate as provide extended depth of focus.
Besides accommodation, an additional benefit of some accommodating IOL designs involves the potential to exchange the variable power optic for those lenses that use it. Today, the average age of a cataract patient is about 69.2 If that patient lives to age 80, they have 10 or 11 years with their new IOL. Most patients don’t think about changing the lens, as they’re generally satisfied with the outcome.
However, cataract patients may well consider having surgery at an earlier age, and they are likely to live longer. If that’s the case, implanting a modular accommodating IOL that provides a variable power optic that can be exchanged in the future starts to become attractive. Of course, if a patient heals with residual refractive error, the surgeon can easily exchange the front optics of the lens without prying apart the surfaces of the lens capsule.
Imagine that we can tell patients that we are implanting a platform that can serve their needs today and into the future. For instance, a 65-year-old patient may drive and play tennis and need a lens that provides primarily excellent distance vision. But as the patient ages and stops those activities, we can potentially change the lens optic to provide optimal close vision.
For these patients, such flexibility would doubtless drive adoption. Price would become potentially a nonfactor, as patients recognize that a lifetime of quality vision is truly a prize to be had.
In addition, this flexibility could drive interesting changes in eye care, including earlier refractive lensectomy or cataract surgery for plano presbyopes. Right now, the hardest-to-please patients are those who are presbyopic but plano. For these patients, having a lens that could restore accommodation would be a significant advance.
Challenges to Meet
Notwithstanding the great promise of accommodating IOLs, they are not without their challenges.
First, most accommodating IOLs today depend on predictable behavior of the lens capsule and ciliary body. In other words, most require a round, centered capsulotomy of a given diameter. Surgeons can achieve that goal today working by hand but generally not with complete consistency. Femtosecond lasers and precision pulse capsulotomy devices, such as the Zepto IOL Positioning System (Centricity Vision), certainly help. Some of these lenses may require that kind of capsulotomy precision.
Second, accommodating IOLs depend on predictable capsular healing. Significant fibrosis or contraction of the capsule could alter functioning: it could interfere with correcting the basic refractive error; affect the linkage between the ciliary body, the zonules, and the lens; and alter the range of accommodation or its longevity.
Third, these IOLs will require surgeons to adapt to this new technology. Accommodating IOLs don’t look anything like the 1-piece lenses that surgeons implant in the eye today. They will require adapting to such elements as a new type of injector, a potentially larger incision size, and a very different form factor of the lens itself. As a participant in the FDA trials of accommodating lenses, I can attest that some of these lenses can be somewhat daunting to implant, with “parts” that stick out at unusual angles and unfold in very unfamiliar ways.
Delivering on the Promise
Accommodating IOL technology is in its infancy, and the lenses we see today are first-generation efforts. What we may eventually have in our hands could be much better than current initial results.
Patients are willing to pay for these technologies, and surgeons are motivated to use them. These factors mean an accessible market, with decent margins for the products and distribution channels that are well established. If we can achieve the technological goal, we can probably have a very successful, commercialized product.
As noted above, 2 surgeons have added comments regarding their experiences:
George O. Waring IV, MD
Founder and Medical Director of the Waring Vision Institute, Mount Pleasant, SC
The OmniVu IOL is designed to address the effects of presbyopia by harnessing the natural lens-accommodating mechanism of the eye. The IOL features a shape-changing, fluid-filled base and a fixed-power front optic that are paired to achieve the desired refractive outcome.
The fixed-power front optic is made from a hydrophobic acrylic material, with 3 docking tabs around the 5.6-mm optic. The shape-changing fluid-filled base shell has an inner channel, which allows for the docking of the fixed power front optic.
The key to this design is that the ciliary muscles exert force on the capsular bag, which results in changes in base optic thickness and curvature and therefore in power, aimed at restoring a full range of vision.
We recently presented the first-in-human 6-month interim data at the 2023 American Society of Cataract and Refractive Surgery (ASCRS) annual meeting. In summary, 95% of eyes were found to be within 0.5D of plano at 6 months postoperatively. All patients achieved binocular distance-corrected visual acuity of 20/20 for distance and intermediate and 20/32 for distance-corrected near. The patients were found to maintain greater than 20/32 across 4D of defocus binocularly, and refractive predictability and stability were stable and consistent.3 We now have follow-up out to 12 months, and we look forward to reporting these data in a subset of patients in the future.
The surgical technique would be intuitive to cataract surgeons. The base lens is inserted through a 3.5-mm incision into the capsular bag after a normal standard phacoemulsification procedure with an intended 5.5 mm-diameter capsulotomy. Then, the fixed power front optic lens is injected into the capsular bag and docked into the base under the blue tabs.
Sumit (Sam) Garg, MD
Professor of Ophthalmology and Medical Director, Gavin Herbert Eye Institute, University of California, Irvine
The Juvene IOL (JIOL) is a novel, modular, 2-piece silicone IOL composed of a base lens (BL) and fluid lens (FL). The BL comprises a circumferential blue haptic and carries a clear central optic. The FL has a clear posterior optic and a flexible anterior surface filled with proprietary silicone oil. The FL fits into the BL under 3 haptic tabs to complete the JIOL system.
The designed mechanism of action utilizes a transfer of natural capsular bag forces to the BL haptic, causing compression of the FL and subsequent anterior curvature change of the FL. This process results in a power change with near viewing effort, allowing for a continuous range of vision from distance to near. While the precise mechanism of action of the JIOL is still under investigation, laboratory and initial clinical results support an anterior curvature-changing dynamic mechanism. Past in vivo studies have shown that the evacuated capsular bag is still capable of transferring forces during accommodative effort, lending credibility to the JIOL’s proposed mechanism.
Current diffractive IOLs have limitations on patient candidacy, which are well known to refractive cataract surgeons. Thirty-six-month efficacy and safety data were presented at the 2023 ASCRS annual meeting. Monocularly, mean corrected distance VA was 20/18, distance-corrected intermediate VA was 20/26, and distance-corrected near VA was 20/35, further improving with binocular summation. Additionally, there were no safety issues and no formation of posterior capsule opacification, and endothelial cell count loss was comparable to that with conventional cataract surgery. Importantly, these patients had excellent contrast sensitivity and minimal complaints of dysphotopsia, according to a direct questionnaire. Furthermore, they maintained their accommodative amplitude over the 3-year study period.4
To date, the JIOL has the longest public track record of clinical results. The modular design of the lens allows for insertion through a 3-mm incision, with very little change to the standard cataract surgical procedure. The modular feature of the lens theoretically allows for ease of IOL exchange, if needed, but also the ability for easy “upgradeability” as the technology matures. With respect to patient selection criteria, the JIOL will make the discussion with the patient much more straightforward compared to that with currently available diffractive IOLs. The biomimetic mechanism of action is quite understandable for patients. Additionally, many of the factors that preclude patients from contemporary presbyopia-correcting IOLs are not restrictions for the JIOL since the lens offers monofocal-like quality optics with added nondiffractive range of vision. ■
- Koury C. Adjustability: the ‘holy grail’ for IOLs? Ophthalmol Manag. 2023;27(8):27-30.
- Kauh CY, Blachley TS, Lichter PR, Lee PP, Stein JD. Geographic variation in the rate and timing of cataract surgery among US communities. JAMA Ophthalmol. 2016;134(3):267-276.
- Waring GW. Prospective, open-label, non-randomized trial of a presbyopia-correcting, modular intraocular lens system for treatment of cataract. Paper presented at: Annual meeting of the American Society of Cataract and Refractive Surgery; May 5-8, 2023; San Diego, CA.
- Garg S. Thirty-six-month visual outcomes after implantation of a new modular, shape-changing, fluid-optic intraocular lens. Paper presented at: Annual meeting of the American Society of Cataract and Refractive Surgery; May 5-8, 2023; San Diego, CA.