BLOG: IOL state of the union

In this column, I continue to review and highlight current and emerging trends in cataract surgery.

Improvements in IOL technology — particularly trifocal and extended-depth-of focus options — are top of mind as cataract surgery moves ever closer to truly correcting presbyopia and providing patients with crisp, youthful (spectacle-free) vision at all distances.

Intermediate distance

With increasing use of smartphones, tablets and laptops, intermediate vision has become more important to patients, and extended-depth-of-focus (EDOF) IOLs seek to better meet this demand. Unlike traditional multifocal IOLs, which generate two or more separate focal points for defined viewing distances, EDOF lenses provide a single, elongated focal point with an increased depth of focus. The design is associated with potentially less negative impact on quality of vision compared to traditional multifocal lenses. Having a larger “sweet spot,” they also place less demand on the surgeon to achieve emmetropia.

In the U.S., the Tecnis Symfony IOL (Johnson & Johnson Vision) represents the first of these lenses to be FDA-approved. The implant employs a biconvex wavefront-designed anterior aspheric surface and a posterior achromatic diffractive surface with an echelette design. This proprietary format creates an achromatic diffractive pattern elongating to a single focal point and compensating for the chromatic aberration of the cornea.

Make it personal

Another example of a wider range of vision implant is the trifocal. These lenses combine two diffractive profiles to improve the spectrum of spectacle freedom. Many experts are optimistic that this technology, not yet available in the U.S., offers excellent potential for visual outcomes. The FineVision IOL (PhysIOL) was the first to become available in Europe.

Different trifocal and EDOF designs rely on varying mechanisms, including use of achromatic IOL technology, zones with different aspheric profiles and the pinhole effect. Trifocal and EDOF lenses also come with toric correction enabling surgeons to further give patients the best possible uncorrected distance visual acuity.

With the availability of the wide range of Tecnis Symfony toric lenses, for example, surgeons can achieve more personalized vision. Depending on patients’ preferences and visual needs, a “mix and match” approach using the full portfolio of available technology enables fully personalized cataract outcomes.

On the horizon

Many experts say that true accommodative design strategies for IOL technology still have not been perfected. Those that rely on shape-related changes in the surfaces of the implant or dynamic changes to the refractive index may be coming to the forefront. Fluid-optic accommodating IOLs (eg, Juvene by LensGen and FluidVision by PowerVision), are being investigated in trials outside the U.S. and in early clinical work.

The FDA approved an adjustable IOL 2017, the Light Adjustable Lens (RxSight). The implant can be adjusted after surgery in the office using the company’s UV light delivery device. Similar concepts use femtosecond laser technology to induce a chemical reaction to achieve refractive index shaping (eg, Perfect Lens).

Another concept in the realm of exchangeable lens technology is represented by the Gemini Refractive Capsule (Omega Ophthalmics). The implant is designed to neutralize the variable of effective lens position to achieve predictable visual results. The defined plane in the middle of device implant securely holds a separate IOL in place. If the patient’s visual status changes, the IOL could be exchanged for the best available technology at that time.

As the quest for ever more perfect methods of presbyopia continues, the horizon is full of newly conceived advances as well as those that rely on well-established concepts. Eye care providers are advised to consider all the premium IOL technology available today while always remaining poised to incorporate new approaches when the time is right.

References:

Cochener B, et al. J Cataract Refract Surg. 2016;doi:10.1016/j.jcrs.2016.06.033.

Cochener B, et al. J Refract Surg. 2018;doi:10.3928/1081597X-20180530-02.

de Medeiros AL, et al. Clin Ophthalmol. 2017;doi:10.2147/OPTH.S145945.

Savini G, et al. J Refract Surg. 2018;doi:10.3928/1081597X-20180125-01.