Choosing the right order: doctor and a lens

Yes Bookwoman!

Sorry, but I can't agree. A poor lens put in by a good doctor is still a poor lens. Unfortunately the reality today in most clinics that do cataract surgery is that they are tied to one manufacturer of lenses. When you have picked the surgeon, you have essentially picked the lens. But yes for sure you want a good surgeon. However there are good surgeons doing most of the more common lenses.

IRon

I think the main monofocal iols are all pretty good. J&J , Alcon, B&L.

Yes, good, but there are differences especially in asphericity. The Tecnis 1 targets zero net asphericity and potentially gives the best visual acuity but the poorest depth of focus. The B+L enVista has the most residual asphericity and compromises visual acuity some, but gives the most depth of focus. The Clareon falls in between. So, I guess it depends on one's knowledge of what the lenses offer and priorities.

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There is also the issue of having blue light filtering or not.

I would add that, as I have said before, you want a skilled surgeon, but also one who will listen to you, work with you, and one you feel comfortable with. I know of some skilled, experienced cataract surgeons who use the Tecnis 1, but they won't try telling patients about refractive target outcomes. They will just aim for distance and use glasses to correct for near vision.

Yes, those are all important factors to consider too.

ron, please explain "asphericity again please

and what is the issue w blue light filtering?

Asphericity:

This is a measure of the sharpness of the focus of light from all parts of the lens. Zero net asphericity is when all light from the edge of the lens to the center is brought to the same focus point. The Tecnis 1 lens theoretically has zero asphericity. It can provide the sharpest focus at distance (if set for distance) but will not have the depth of focus at closer distances. A lens like a B+L enVista has +0.27 um of asphericity in the average eye. The sharpness of the focus is a little reduced, but the depth of focus is increased allowing one to see a little closer with a lens set for distance. The Alcon lenses are somewhere between these two for asphericity.

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Blue Light Filtering:

The young natural eye has blue light filtering. Most Alcon lenses have blue light filtering to match the colour balance of a young natural eye. Most J&J lenses have no blue light filtering and yield a more blueish colour balance. However more recently J&J have been offering some models called OptiBlue that have some blue-violet light filtering. The advantage of blue light filtering is a more natural colour balance, and to some degree possibly higher contrast sensitivity in dimmer light conditions. The filtering takes out some of the chromatic aberrations in the lens.

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I will post a grahic on the asphericity issue in a separate post. It will get delayed in moderation, so check back tomorrow...

Here is a graphic from B+L that shows the tradeoff of asphericity vs visual acuity of the common lenses. I added the red dot as to where I think the J&J Eyhance lands on the curve. The Clareon lens would land in the same spot as the AcrySof lens on the graph.

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thank you ron. but why exactly does somebody get an aspheric lens as opposed to a non aspheric?

and does the j&j tecnis one have blue light filtering? and if its an advantage to have that, why would any lens NOT have it?

Prior to 2010 or so, most lenses were non aspheric. They were brought out as a claimed improvement to visual acuity. In good eyes they probably do improve visual acuity some. However they were controversial at the time as some claimed there was no real improvement, and the non aspheric lenses were more tolerant. They had a price premium associated with them, and many public health and insurance companies did not pay for the extra cost. Now most do.

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On blue light filtering, not everyone puts a value on having a colour balance the same as young person with a natural lens. Photographers who do digital dark room work probably are the ones that would (should) appreciate it the most. Not sure which lenses that J&J offers the OptiBlue. They must have thought they were losing some of the market share by not offering blue light filtering. Optically their lenses probably benefit from it by reducing chromatic aberration.

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Alcon on the other hand offers non blue light filtering lenses, probably just to appeal to the people that do not want it. Unfortunately blue light filtering is not well understood, and some think it is a disadvantage. They obviously do not want to miss out on that market.

Does "non aspheric lens" mean something different from "spheric lens"?

The earlier IOLs were called spheric, but I am not sure what that really means. My recollection from B+L enVista information that a "spherical" lens leaves you at a positive asphericity of +0.37 um. That is composed of the +0.27 um that the average person has from their cornea plus an addition of 0.10 um from the "spheric" lens. So there is a whole range of aspherical lenses on the market. If you look back at that B+L graph I posted you can see what they are, with the red dot as my estimate of the Eyhance. A spherical lens on this chart would then end up at -0.37 um further off to the right of the enVista, but is not shown. It would have the highest depth of focus and the greatest loss in visual acuity.

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To my thinking the B+L enVista which does not add or subtract any asphericity and is in their words "neutral" would be an example of a true optically spherical lens, but that does not appear to be the case.

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If someone was on a tight budget and having to pay the whole cost of an IOL out of their pocket, and are willing to give up a little more visual acuity to get the most depth of focus, there could be value in finding someone that still implants the "spherical" lens. I believe in third world countries they may be still the standard. And they may be a hard lens instead of a foldable one.

Without regard to matching the far eye, what lens would you select today for your near eye? Premium OK.

My second eye was done with a Clareon non toric lens. If I had it to do all over again the only thing I would change is that I would get a toric. In hindsight a non toric was a mistake. At the time a Clareon toric was not available, but I believe it is now. And, again if I could roll back time, with the Clareon toric not being available I should have selected the AcrySof IQ Toric. The Vivity was a consideration, but I have no regrets about passing on that option.