Patients often ask me if any of the new lens designs will give them youthful vision. The truth is that none of them well. As the saying goes, youth is wasted on young people. When we are young, night vision is great, retinal sensitivity is high, and the level of accommodation is amazing. With time, the retinal sensitivity decreases and the accommodation diminishes. And with old age, cataracts develop which further decrease visual quality. While we have a youthful accommodative lens design in development, it will likely be about 10 years before it’s available.
There is no question, if you want the best possible night vision, then a monofocal lens is your best option (Figure A), but you must be willing to use over-the-counter reading glasses. That means no glasses from about extended fingertips to far distance but then requiring glasses for near and intermediate work like computer, books, cell phone use, and more. Using these lens implants in with slightly different focal points (monovision or mini-monovision) can give a wider range of vision without spectacles. And of course, those patients who prefer the near vision can aim for a post-op goal of mild myopia and then wear spectacles for far vision.
The Alcon ReStor multifocal lens implants (Figures B, C, and D) come in three different designs in the USA: the 2.5 add, the 3.0 add, and the 4.0 add. And each of these has a different near focal point of about 50 cm, 40 cm, and 30 cm, respectively. (The add powers are at the IOL plane so conversion to the spectacle plane must be done, this is why the ReStor 2.5 add functions like +2.00 reading glasses). For patients who may be reading this website and who prefer the imperial units, this corresponds to 20 inches, 16 inches, and 12 inches. The same figure is produced below with near point shown in inches.
These images are from a study that was published in February 2018 in the journal Clinical Ophthalmology (21 February 2018 Volume 2018:12 Pages 385—393. link here) from authors Carson D, Lee S, Alexander E, Wei X, and Lee S. They are simulated images from laboratory testing where the lens implant acted as the lens of the camera to give a very accurate simulation of actual patient vision.
The differences in design of the Alcon ReStor models shows that the newest 2.5 add lens is more distance dominant and the night vision is closest to the gold standard Alcon IQ monofocal lens. The 2.5 add lens also emphasizes the computer distance (50 cm or about 20 inches), which is becoming a more important task in our daily lives. This entire website that you’re reading was created on a computer screen about 50 cm away from me.
The extended depth of field lenses (EDOF) are newer to the US market and they purport to have the benefit of a wider range of vision but without the compromises of multifocal lenses. From the image testing done here, we can see that the EDOF AMO/J&J Symfony lens (Figure E) simply does not have the same quality night vision as the gold standard monofocal IOL. The AMO/J&J Tecnis +2.75 multifocal IOL shows a different type of night vision compromise compared to the EDOF Symfony IOL, but it may provide better near vision without spectacles.
None of these lens designs is perfect. And none of them will restore the youthful vision of a 25 year old to our typically geriatric cataract patients. There are new designs that are available in other countries such as the Oculentis M Lentis, the Alcon Panoptix Trifocal, the Zeiss Lisa series, and more. But even with these new designs, there will be some compromises because you simply cannot cheat the physics of optics. It is up to us to help our patients determine which design is best suited to their desires and which compromises our patients will accept.
if you are a patient, choose one sentence that best describes your desires:option 1: “I want the best quality vision at all times and I will happily wear over-the-counter reading glasses for computer, cell phone, and reading.”oroption 2: “I don’t want to rely so much on reading glasses, and to achieve that I will happily tolerate decreased quality of vision, particularly at night.”
All content is © 2018 by Uday Devgan MD. All rights reserved.