kimknapp wrote:
Thanks all.
I suspect that since I have worn eyeglasses since I was about 13 and they always had UV protection built in, they have kept me from getting bad cataracts, so far. As a result, I decided to use some more time to evaluate the different options for when I do have cataract surgery.
The doctor felt that the new Alcon Vivity would be perfect for my lifestyle (active, lots of hiking, biking, birding and, of course, photography), but I am finding that they are so new that there is very little result-based news online. There is a long term test being done with exactly the type of info I am interested in, but the report won't be done until later this year.
Marketing literature such as "our tests show that 94% have at least 20/25 vision" just isn't good enough.
As I mentioned in my first post, these are not multi-focus lenses, with potential halo issues. Instead, they are extended depth of field lenses, but they won't say how they work.
At 72 and having worked in technology my whole life, I know how easy it is to get burned by the "latest thing", hence I am happy to wait a bit longer, especially since my cataract are very mild and those lenses sound interesting.
Kim
One can evaluate these lenses to some degree as picking out a new lens for one's cam. The "no free lunch" rule of optics applies. Look at the MTF curves for a 3mm aperture and see how Vivity works.
The link is to the package insert approved by the FDA. Sometimes they plot these out to make them look a bit better--still accurate but can be misleading by the scales used.
See page 4: As this is a SINGLE lens there is only so much resolution to go around so what is done is to rob Peter at plano (infinity) to pay Paul at intermediate and near distances. This can be a good compromise especially if both eyes done and the adjustments offset a bit. If one desires max MTF than get a good standard monofocal IOL and use lenses to shift the focus--i.e. spectacles. This lens is not a diffractive multifocal optic that robs photons for each focal length. The multifocal diffractive optics (eg, a trifocal) result in using only 1/3 available photons at each focal length. Contrast sensitivity and low light performance is reduced. Some also use a small aperture to improve dof but I don't want my eye at f22 all the time necessarily unless being spectacle free is the priority. Also dysphotopsias can occur using diffractive optics with starbursts, halos, flare etc. This does NOT happen with Vivity.
Now look at the Defocus curve on page 14-- 0 diopter is infinity, -1 diopter is for an object at 1meter, -2.5 diopter is 40 cm. So the Vivity is very very good at intermediate distances and so-so at reading. It robs some resolution at infinity to accomplish this trick. (No free lunch) The lens has toric version to correct astigmatism too but that can be very tricky to accomplish. Sometimes despite meticulous measurements the perfect lens is not chosen--I think Vivity is more forgiving with this due to the design.
There is a similarly designed EDOF (enhanced depth of focus) lens call Eyhance (and just recently available like Vivity) but that is rather more like a slightly modified mono-focal and I don't think is treated by Medicare as a "premium" lens. That only robs about 0.5 diopters from infinity for intermediate vision. I would only expect modest benefit at intermediate distances compared to a monofocal and I don't even think the manufacturer was able to show a statistically significant improvement.
What everyone wants is for the lens to act like one is 20 yo again and perfect accommodation for intermediate/ near vision. They are under development and one would expect everyone in 10 years will get those and be driving eclectic cars. Look up the Grail study using Juvene---it is very cool with a modular design and fills the capsular bag preventing PCO (posterior capsular opacification) The front part is the optic that can thicken as the ciliary apparatus contracts. I don't believe they have started the pivotal trial to get it approved in the US yet. One suspects it will be 5 years at least but one can hope. This is a big deal and multiple solutions have been devised and under development.
Bottom line is that these are lenses like any other and evaluate and shop accordingly. Admittedly most have Leica prices but I can't think of a more important lens. One needs to understand the strengths/shortcomings of each IOL choice and discuss in detail with the ophthalmologist based on the individual circumstance/measurements.
I am an endocrinologist, not an ophthalmologist but no one on this august list should be intimidated by any lens choice or feel under informed.
Sep 30, 2021 at 05:19 PM
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