Deciding on IOLs, how did you all choose whether to get aspheric (toric) lens?
Posted , 3 users are following.
Hello all,
I've been lurking on this site for a while now, soaking up all the knowledge and helpful experiences for weeks. Now I'm getting close to choosing and am stumped on the aspheric/no aberration issue.
Background, I'm 56, in the US, and starting with my right (dominant) eye, where the cataract is worse. My surgeon uses Alcon lenses, so my choice is between the monofocal Acrysof IQ or the EDOF Acrysof IQ Vivity. Originally I was thinking of going ahead with the Vivity, going either for plano in both eyes or for mini-monovision of around -0.1D. I'd love to be glasses free for all but deep reading (have worn them for years after my Lasik at 40 years old wore out). Then I started reading posts and studies about the decrease in contrast sensitivity with Vivity, particularly with the mini-monovision...
So, now I am thinking to get the monofocal in my right eye, set for distance and get a Vivity set for +/- .75D in my left eye but now I have the question of whether to get a zero aberration or a negative aberration lens for each. I have a moderate astygmatism in my left eye ( the one I'd get the Vivity in) and a mild astygmatism in my right eye. The studies I've read are all over the map: some say patients can't tell the difference between a standard and a neg. aberration lens; others say the negative aberration lens gives measureably better night driving, low light contrast sensitivity, and MTF, where the 0-aberration lens gives better near vision (probably due to some residual spherical aberration).
For those of you who have either studied this or have made this decision already, how did you decide and what do you think of your choice? Of course, I'm also going to discuss this with my surgeon (he's great), but I also wanted to "ask the audience" because you all are a wealth of experience. Thanks!
0 likes, 6 replies
RonAKA tracy9999
Posted
I have looked at this issue and considered Vivity for my second eye. I already have the AcrySof IQ Aspheric in my first eye which is set for distance. The aspheric lens is the standard my surgeon uses and the cost is covered by our government healthcare system. So I never really considered the non-aspheric version. I really see no advantage in the non-aspheric version other than perhaps a cost savings. Although I suspect in the scheme of things the difference is minor. I ended up with 20/20+ vision in the eye, with a 0.0 D spherical eyeglass correction. I do have some residual astigmatism. The lens used was non toric as I did not have a high enough astigmatism to correct with a toric lens. You mention that you have some astigmatism. Keep in mind that eyeglass cylinder measure for astigmatism includes astigmatism in the natural lens plus that in the cornea. Since the natural lens is being removed, only the corneal astigmatism counts when selecting the IOL. Whether or not you need or could use a toric lens can only be determined after the surgeon measures the topography of your cornea. They don't recommend a toric lens unless the astigmatism in the cornea is more than 0.75. If under that, the minimum power toric would over correct for it.
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I never considered Vivity for my first eye as it was not available at that time. After looking at the pros on cons of using it for my second eye, I think I will go with the same monofocal lens but with -1.25 D under correction - mini monovision. I am currently simulating that using a contact lens in my non operated eye, and am liking it. Staying with a monofocal will maintain the higher contrast sensitivity although it will be moved to a closer focus distance. I think the Vivity may give me a little better distance vision, but perhaps not quite as good a close vision. If I went with the Vivity in the close eye, I would ask for a -0.75 D monovision. I could be wrong, but I don't believe the Vivity is available in a non aspherical version.
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One lens you may want to consider if it is available where you are located is the new Alcon Clareon. It is very similar in design to the Alcon AcrySof, but uses an upgraded material. It is supposed to be more resistant to glistenings. I don't think that is a significant issue, but if the price is the same, the newer material may be the way to go... If you google this phrase you should find some information on it.
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Clareon IOL: A New Monofocal Platform
tracy9999 RonAKA
Posted
Hi RonAKA,
Thank you for your reply -- exactly what I was looking for. I wondered if it was a "game time decision" by the surgeon on whether to use a toric lens or not. Some of the studies I read found that leaving some residual astygmatism aids in near vision, so I thought to use a 0-aberration IOL in my non-dominant eye to leave a little once the lens is removed. Obviously I'll discuss with my surgeon when it comes to doing that eye later.
With the mini-monovision you're planning, will you need readers for all reading? What about for computer work? I don't know what the practical impact of -1.25 D is. I'm thinking that mono-vision isn't right for me since I don't want to leave a gap in the intermediate vision distance but also don't want to wear reading glasses all day. I am on video calls much of the day at my computer and really want to lose the glasses for that work if I can. I don't mind wearing them if I'm reading a book. I'm thinking Vivity in my left eye, about -.75 D might just allow this and still keep the contrast sensitivity strong in my right eye.
I will check out the Alcon Clareon to see if my surgeon can get it. They stick with the Alcon brand, so I don't know why he wouldn't be able to use it.
RonAKA tracy9999
Posted
I think it is true that some residual minus astigmatism can aid in being able to read better. With my IOL eye I was left with -0.75 D astigmatism and while I see 20/20+ at distance I can also see down to about 20" reasonably well. Not sure one would want to do it intentionally but small amounts of astigmatism is probably not worth correcting.
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Don't confuse astigmatism with spherical aberration. Astigmatism is when the power of your cornea is not uniform around the circumference; - 0 to 360 degrees. That is why the power for cylinder correction has an angle associated with it. Part of your eye is different than another. Typically it is symmetrical in an hour glass shape, but not always. Spherical aberration is when the power is different based on the radius of your eye. It results in a less sharp focus. And I suspect that is how the Vivity lens gets the EDOF vision, and at the same time compromises contrast sensitivity. It seems a bit rich to me that they claim it to be an aspherical lens but at the same time say it is EDOF...
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With my simulated mini monovision I am eyeglass free 95% of the time. I basically take my contact out at 9:00 PM or so in the evening as it can become irritating if I wear it too long. I don't see a gap in closer vision. In a store I do see less crisply at 50 feet or so. I suspect that is because I am seeing with one eye sharply and the other eye less sharply, while my brain is trying to decide which one is the best. I don't need glasses unless I am reading very fine print on a OTC drug label or something like that. I rarely use readers, and just use a pair that is a bit too strong that was lying around the house when I need to see something in full detail close up. I hate it when I look up with the readers on and everything is out of focus, so they are gone as soon as my very close vision requirement is gone. I use a computer much of the day and watch TV at a distance at the same time. Not a problem at all without glasses.
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I do have progressives which I wear when I want the very best vision. They are the least used pair of glasses I have ever owned! Currently it is a bit of a pain to use them as I have to take my contact out first. When I have IOL monovision that will not be an issue. I can just put them on when I need them, like readers, and take them off when I don't. That will be much more convenient.
RonAKA tracy9999
Posted
"I wondered if it was a "game time decision" by the surgeon on whether to use a toric lens or not."
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No, that would not be the normal practice. Normally you have a pre-op appointment well before the surgery day where they do the detailed measurements of the eye topography. That is when they would decide whether or not a toric would be suitable. Then they have the appropriate power lens and type ready at the time of the surgery. Be aware that prior Lasik surgery can complicate the measurement process.
tracy9999 RonAKA
Posted
Great explanations -- I didn't know the difference between astigmatism and spherical aberration! I didn't think I'd need to learn so much about all of this in order to get my cataracts removed. It's been an education, but a very important one.
I appreciate knowing your experience with monovision and the contact lens and glasses. I'm going to take it one step at a time and see how my vision is with the single corrected distance eye before moving to the decision about my left non-dominant eye. I can't wear contacts, so trialing monovision won't work for me. I'm glad you've got a result you like (for now) and can make it work before getting the other eye done.
tracy9999 RonAKA
Posted
Good to know about the pre-op (obviously haven't gone through that part yet). I had read that given my previous LASIK there might be additional challenges both in the procedure and in my result. The surgeon uses the latest laser for the incision and computer-aided measurements, so hopefully that will help with both. I"ll know more after the pre-op. Thanks again for all the great info. You've been a real help to me.