New IOLs continue to help surgeons meet needs of individual patients
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In Canada, we have gained access to several new IOLs in recent months that help to round out our slate of lens offerings for patients in both the monofocal and presbyopia-correcting categories.
Presbyopia-correcting options
The first of these is the Tecnis Synergy ZFR00 IOL (Johnson & Johnson Vision), which combines features of a multifocal and extended depth of focus lens. The lens has two distinct focal points at near and distance, with advanced diffractive optics providing a continuous range of vision from near to intermediate, or from about 30 cm to 70 cm. In my experience thus far, patients experience a full range of vision that is similar to what the bench testing defocus curves for the lens predicted.
We have already had good EDOF and trifocal IOLs in our armamentarium, and these have provided excellent patient outcomes. The Synergy lens has a better near point than the Tecnis Symfony, which has the EDOF optics in the intermediate to distance range. It also has a closer near point than the trifocal lenses, along with the continuous range that allows patients to move an object in the near range without losing the focal point. There are some theoretical benefits of the material and design that are yet to be confirmed in head-to-head clinical trials. These include reduced LED-based dysphotopsia from the violet-filtering chromophore and, more importantly, the potential for the active chromatic aberration correction to reduce the impact of multifocality on contrast sensitivity (CS).
I do counsel patients to expect glare and halo and some loss of contrast at night, but my impression thus far is that there is less impact on CS with this lens compared with previous multifocals. Confirmation of this in published studies would be beneficial.
I recently implanted bilateral ZFR00 lenses in a young 45-year-old patient with posterior subcapsular cataracts. She was a –3 D myope habituated to removing her glasses to read. In my experience, these are among the most challenging patients to satisfy with multifocal IOL technology because their natural near vision is hard to match. One month out, my patient is happy with her full range of vision and has not experienced any loss of CS or difficulty driving at night.
Another new option for presbyopia correction is the Alcon AcrySof IQ Vivity IOL (DFT015). This lens relies on nondiffractive technology to extend the depth of focus. The anterior surface of the IOL has two surface transition elements that work simultaneously to stretch and shift light, creating continuous vision, rather than separate focal points, which is an interesting new approach. In my experience so far, this lens broadens the focal point to provide patients with intermediate vision and some improvement in near, with minimal CS loss. One of the hallmarks of this lens based on registration trials as well as our early clinical experience has been the lack of night vision disturbances such as halos and glare, which is potentially a major development.
I view both of these lenses as a continuation of the rapid evolution of presbyopia-correcting IOL technology, improving and expanding upon the options we can offer patients.
Monofocal innovation
Another new lens I recently began using is the Eyhance ICB00 (Johnson & Johnson Vision). This IOL fits into a unique “enhanced monofocal” category. This lens relies on a subtle power change from the center to the periphery to boost intermediate vision just a little bit, without the compromises inherent in multifocal or EDOF presbyopia-correcting IOLs. Optical bench testing suggests a gain of approximately one line of vision in intermediate acuity, while a recently published clinical study demonstrated that the intermediate boost came with no significant differences in photopic CS, scatter, modulation transfer function cutoff, Strehl ratio, or glare and halo perception compared with the Tecnis ZCB00. Innovation in the monofocal lens category has been limited in recent years, so it is exciting to see something new to benefit our patients who cannot afford or do not qualify for a presbyopia-correcting IOL.
Both the Eyhance and Synergy IOLs have the same A-constant as other IOLs in the Tecnis family. This provides a level of consistency in reducing the potential for errors in IOL power calculations — a small but practical advantage for users of other lenses on this platform.
I recently implanted bilateral ICB00 IOLs in a 78-year-old cataract patient with comorbid age-related macular degeneration. As a monofocal lens without compromise on CS, this IOL is suitable for patients who are not good candidates for a true presbyopia-correcting IOL, such as those with AMD, Fuchs’ dystrophy or other conditions in which I would not want to risk the loss of a percentage of the light reaching the retina or further reduce already-compromised CS. I was careful to explain that he would definitely need glasses for reading or spending prolonged time at the computer, but this patient enjoyed the benefit of being able to do at least some of his daily tasks, such as reading larger print and seeing more of the car dashboard without glasses.
In a difficult year of the pandemic, it is great to see lens innovations brought into our hands and into our patients’ eyes. As the number of EDOF, multifocal and enhanced monofocal lenses expands, we continue to customize cataract surgery to the needs of each patient.
- References:
- Alarcon A, et al. J Refract Surg. 2020;doi:10.3928/1081597X-20200612-01.
- Mencucci R, et al. J Cataract Refract Surg. 2020;doi:10.1097/j.jcrs.0000000000000061.
- For more information:
- Ike K. Ahmed, MD, FRCSC, can be reached at Prism Eye Institute, 2201 Bristol Circle, Suite 100, Oakville, Ontario, L6H 0J8, Canada; email: ikeahmed@mac.com.
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