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There are a number of ways to improve near vision for presbyopes, including multifocal intraocular lenses (IOLs)–traditional or low add–and pseudoaccommodative IOLs. It has been well documented that a small pupil and higher order aberrations, such as spherical aberration (SA) or coma, can increase depth of focus.
There are a number of ways to improve near vision for presbyopes, including multifocal intraocular lenses (IOLs)–traditional or low add–and pseudoaccommodative IOLs. It has been well documented that a small pupil and higher order aberrations, such as spherical aberration (SA) or coma, can increase depth of focus.1
In combination with some degree of monovision, this may enable some patients to have good near vision with a monofocal IOL or a corneal refractive treatment. However, there may be tradeoffs in terms of visual quality.
The ophthalmic industry is beginning to see a new category of extended depth of focus (EDOF) IOLs that are designed to provide a continuous range of focus with fewer limitations than multifocal IOLs or the pseudoaccommodative options described above. These include the Tecnis Symfony IOL (Johnson & Johnson Vision/AMO), which relies on diffractive echelette optics to elongate the focal line, and the small-aperture IC-8 IOL (AcuFocus), which is not yet available in the United States, as well as other designs in development.
Advantages vs. multifocal
The EDOF category offers two advantages over traditional multifocal IOLs. First, it offers a natural range of vision, rather than one or two “sweet spots.”
This can be easy to explain to a patient who has worn bifocal or trifocal spectacles. They understand that each portion of their spectacle lens has a limited range, beyond which there is a blur. While patients can adapt to spectacles or multifocal IOLs with distinct focal points, the idea of having a broader field of clear vision with an EDOF lens is attractive.
Additionally, because EDOF lenses do not split light among focal points the same as a multifocal IOL, there is minimal-to-no loss of distance clarity and contrast acuity. Since patients do not have to suppress the second (blurred) focal point, they are less likely to experience ghosting, haloes, or “waxy” vision. It also lowers my level of concern about the impact of a presbyopia-correcting IOL in the context of other anterior segment conditions.
Because of this, I will consider an EDOF lens for post-refractive eyes (with regular corneal astigmatism and a well-centered ablation bed) and for patients with early Fuchs or mild-to-moderate dry eye disease that responds to treatment. I still do not recommend any presbyopia-correcting lens, including EDOF, for patients with any evidence of macular pathology.
The addition of an EDOF lens to our practice has significantly changed the way I talk with patients about advanced technology IOLs. The lens has more than doubled the share of presbyopia-correcting lenses that I implant–from about 10% of all my cataract procedures to 20% to 25% (See Figure 1).
Figure 1: EDOF IOLs have more than doubled the share of presbyopia-correcting lenses that Elizabeth Yeu, MD, implants in her practice - from about 10% of all cataract procedures to 20% to 25% of all cases. Courtesy of Elizabeth Yeu, MD
We took a careful and pragmatic approach to launching EDOF lenses that some might find unusual. We expected that EDOF lenses would probably not provide the very close near vision that higher-add multifocal IOLs do.
My experience in the past, particularly with the Crystalens pseudo-accommodative IOL platform (Bausch + Lomb), was that if the lens was promoted for “reading vision” or “distance and near” vision, patients expected to see everything at near without reading glasses, no matter what caveats I offered to manage expectations.
Therefore, we position EDOF IOLs within a new refractive package, called “distance-and-computer” vision, and priced it less than the “distance-and-reading” vision package (See Figure 2).
This approach helps educate patients about the strengths of EDOF IOLs, while avoiding unrealistic expectations. We were comfortable pricing a new IOL lower than the multifocal IOL package because early data demonstrated that EDOF lenses are more tolerant of residual sphere or cylinder, so there was less need to build in coverage of laser vision correction enhancements.
Figure 2: Elizabeth Yeu, MD, positions EDOF IOLs within a new refractive package called “distance-and-computer” vision. The practice prices it less than the “distance-and-reading” vision package.
After three months and 65 cases, patients are achieving excellent distance and intermediate vision, so they are able to drive and use their computer, tablet, and navigation system in the car without glasses. A pleasant surprise has been that the near vision seems to be consistently between J2 and J5.
Most patients can read newspaper print (J3) unaided, particularly if I give them a - 0.25 D offset in the nondominant eye. This makes patients happy because we have exceeded their expectations.
Initially, the three-tiered pricing is an excellent way for surgeons to introduce the lens and gain experience with the EDOF category and what it can deliver for patients. I plan a more detailed review of the near-vision results after 100 cases. At that point, I may eliminate the middle package and charge the same for multifocal or EDOF.
Customizing IOL education, selection
We try to provide a thorough educational experience when patients come in for a cataract evaluation. Their time starts with specific questions that help the surgeon figure out how to customize IOL options to patients’ needs:
· How tall are you?
· What reading needs do you have?
· What do you typically do from 8 a.m. to 5 p.m.?
· What hobbies do you have?
· How much night time driving do you do?
Patients are surprised by these questions. When I explain why I am asking, patients appreciate that I am taking the time to learn about their visual needs.
Their answers allow me to customize a solution to what patients really want from their vision after surgery. I am implanting fewer multifocal IOLs and toric monofocals because most patients who want a refractive correction are best served by an EDOF lens.
There is some impact from the pricing approach. Business executives refer to this as the “goldilocks effect,” in which consumers are likely to avoid the “extremes” and feel that the middle price (the distance/computer package, in our case) is the one that is “just right” for them.
It is also encouraging to know that if there is any dissatisfaction after implanting an EDOF lens in one eye, we can choose a monofocal or multifocal for the fellow eye.
It is exciting that the industry is getting closer to having presbyopia-correction options that truly meet patients’ need for a full range of uncorrected vision. The EDOF lenses have fewer of the night vision symptoms that were sometimes problematic with earlier multifocal IOLs.
1. Yeu E, Wang L, Koch DD. The effect of corneal wavefront aberrations on corneal pseudoaccommodation. Am J Ophthalmol 2012;153(5):972-81.
Elizabeth Yeu, MD
Dr. Yeu is assistant professor of ophthalmology, Eastern Virginia Medical School and in private practice at Virginia Eye Consultants, both in Norfolk, Va.
Dr. Yeu is a consultant for J&J Vision/AMO, Alcon Laboratories, and B + L.