3 Monofocal questions
Posted , 8 users are following.
If I had a monofocal implanted for best distance, what is the average patient experience for vision before it gets blurry/isn't crisp? 2 meters out? 1 meter?
Would an Eyehance set to best distance have a noteworthy contrast loss compared to a Clareon monofocal?
If a Vivty was set to -.5D in the non dominant and and either a Clareon monofocal or Eyehance was set in the dominant eye for best distance, I assume a fair amount of my vision would have a good binocular summing effect and depth perception for distance. I'm curious how the intermediate to near would be with this combination.
Any help would be greatly appreciated. Thanks.
0 likes, 24 replies
soks aaron15970
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u r 43 years old so you likely have large pupils. clareon lenses have 6mm refraction over entire lens so that will help. at 47 i was told that eyhance will not help me because the central zone is only 1mm and my pupils are 6mm.
RebDovid aaron15970
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Regarding your questions, first, if by average patient experience you mean in terms of visual acuity, the best sources of information are defocus curves from studies, ideally in peer-reviewed journal articles. Because of my interest in the Eyhance IOL, I've collected monocular and binocular defocus curves for the Eyhance. Some are freely-available, some are paywalled but may be accessible online through your library.
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The journal articles reporting studies of the Eyhance generally compare them to so-called pure monofocals like the Tecnis 1 (on which the Eyhance is based) or, in one or two cases to the Clareon. At plano (0.0 D), the reported results are quite similar. At closer-in distances, the Eyhance generally does better than pure monofocals. (A recent video presentation by an Alcon consultant purports to find substantially similar results between the Eyhance and Clareon, but there are reasons to question them, about which I've written in another thread.)
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At 0.0 D, average of the Eyhance reported mean visual acuities is, at distance, 0.016 logMAR, or 20/21 Snellen; at 1m, 0.111 logMAR, or 20/26 Snellen; and at 66.67 cm, 0.190 logMAR, or 20/31 Snellen. Looking only at binocular defocus curves, the average of the mean Eyhance results is, at distance, -0.015 logMAR, or 20/19 Snellen; at 1m, 0.069 logMAR, or 20/23; and at 57.1 cm, 0.181 logMAR, or 20/30.
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Second, as best I recall, the journal articles find no significant contrast loss as compared to the Tecnis 1 pure monofocal. A freely-available preprint (not yet peer reviewed) article for Springer's International Ophthalmology, "Visual Outcomes and Patient Satisfaction after Bilateral Implantation of an Enhanced Monofocal Intraocular Lens: A Single Blind Prospective Randomized Study", compares the Eyhance with both the Clareon and the Tecnis 1. Although the authors apparently did not test for contrast, they report: "a recent meta-analysis on ehanced monofocal IOLs has reported no increased risk of contrast sensitivity loss or increased incidence of photic phenomena." (Citing Wan KH, Au ACK, Kua WN et al (2022) Enhanced Monofocal Versus Conventional Monofocal
Intraocular Lens in Cataract Surgery: A Meta-analysis. J Refract Surg 38(8):538-546)
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Third, I haven't anything to offer about binocular summation and would be most interested if anyone can explain, ideally with reference to authoritative sources, the impact on binocular summation of the degree of monovision, that is, difference between the refractive results in both eyes. For example, is it a continuous function, a step function, something else?
RonAKA aaron15970
Edited
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Optimal amount of anisometropia for pseudophakic monovision. Ken Hayashi, Motoaki Yoshida, +1 author H. Hayashi Published 1 May 2011 Medicine Journal of refractive surgery
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If you google P930014 Vivity Package Insert you can get a document that is very helpful in determining the depth of vision, and the cost to contrast sensitivity (MTF) with the Vivity compared to the monofocal. The key points in reading a defocus curve is that the limit of good vision is a LogMAR of 0.2, and to get distance from the defocus diopters you divide 1 meter by the diopter absolute value. So -1.0 D is 1 meter, and -2.0 D is one half a meter, for example. And when you do a target offset the whole defocus curve moves in that direction by the amount you offset the target. And, one thing to keep in mind is that these defocus curves are very rough estimates. They have a larger error bar associated with them. They are better than nothing, but are not a precise indication of outcome. A recent Alcon study for example found that there was actually no significant difference between the defocus curve of the Clareon and the Eyhance, despite the claims made for the Eyhance.
Lynda111 aaron15970
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You can search on this forum and find many discussions about the Eyhance, Clareon and Vivity. You can also do the same thing with a regular Google search. There are all kinds of studies out there, and there are a number of well-informed laypersons here. Just don't get "lost in the weeds."
Assuming you live in the USA, my own personal advice is to get several opinions from cataract surgeons who are fellowship trained in Cornea/Anterior Segment Surgery, which means they are specialists in cataract surgery. And find someone who you trust, who takes time with you, and with whom you feel comfortable. That is most important. You can read articles and people here can advise you, but only your cataract surgeon has examined your eyes, taken measurements and will do the actual surgery.
RebDovid aaron15970
Edited
As neither I nor Ron are ophthalmologists, I suggest you do your own research: for example, read articles we reference, when we do so, rather than take on trust what we, or anyone else, says.
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You'll find a fuller reference to, and discussion of, the Springer's International Ophthalmology pre-print in my thread "Preprint: Eyhance Gives Statistically Superior Significant Intermediate and Near Vision vs. Clareon". In Lynda111's thread "Alcon Releases New Study Comparing the Eyhance monofocal with the Clareon monofocal", you'll find some discussion of the Alcon consultant's video presentation and reasons--my reasons, at least--for doubting that it fairly compared the Clareon and Eyhance. In contrast to the Alcon consultant's study, the academic authors of the pre-print declare no conflicting interest.
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Here are some additional studies that may be of interest. They're either freely available on the internet or may be available online through your library. (For example, my library gives me access to the Journal of Refractive Surgery.)
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"Enhancing the Intermediate Vision of Monofocal Intraocular Lenses Using a Higher Order Aspheric Optic", Aixa Alarcon, et al., J Refract Surg., 2020;36(8):520-527
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"Clinical evaluation of a new monofocal IOL with enhanced intermediate function in patients with cataract", Gerd U. Auffarth, et al., J Cataract Refract Surg 2021; 47:184-191
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"Clinical outcomes of bilateral implantation of new generation monofocal IOL enhanced for intermediate distance and conventional monofocal IOL in a Korean population", Wan Kyu Choi, et al., BMC Ophthalmology (2023) 23:157
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"Visual and optical quality of enhanced intermediate monofocal
versus standard monofocal intraocular lens", Nuria Garzon, et al., Graefe's Archive for Clinical and Experimental Ophthalmology (2022) 260:3617–3625
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"A comparison of clinical outcomes and optical performance between monofocal and new monofocal with enhanced intermediate function intraocular lenses: a case control
study", Jungah Huh, et al., BMC Ophthalmol (2021) 21:365
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"Visual Performance and Optical Quality after Implantation of a
New Generation Monofocal lntraocular Lens", Kyoung Hae Kang, et al., Korean J Ophthalmol 2021;35(2):112-119
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"Comparison of an aspheric monofocal intraocular lens with the new generation monofocal lens using defocus curve", Sonam Yangzes, et al., Indian J Ophthalmol 2020;68:3025-9
RonAKA RebDovid
Posted
"As neither I nor Ron are ophthalmologists..."
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However, unlike the very large majority of ophthalmologists, I do have cataract surgery in both eyes in a successful mini-monovision configuration. A smart guy once said "The only source of knowledge is experience."
RebDovid RonAKA
Edited
And as other smart guys have said, "The plural of anecdote is not data." I've had knee replacement surgery; it didn't make me an expert in how to do the surgery, how to examine my knee beforehand and decide on the best course of treatment. And, frankly, it never occurred to me to ask whether there are different brands of replacement joints and, if so, why my surgeon wanted to use the particular one he selected. What I did do was carefully select my surgeon; discuss with him more and less conservative treatments; and make choices that seemed sensible to me in light of our conversations and with his support.
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Cataract surgery is somewhat different because, for example, IOL manufacturers actually direct advertising toward patients/customers and the different IOLs are the subject of studies, often peer-reviewed, that include at least some information intelligible to educated laypeople. Nevertheless, finding a surgeon in whom one has confidence is of prime importance.
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Or, as was written a long time ago: "He that Consults his Physician, and will not Follow his Advice, must be his Own Doctor: But let him take the Old Adage along with him. He that Teaches Himself has a Fool to his Master." 1692, Fables of Aesop and Other Eminent Mythologists with Morals and Reflecions by Sir Roger L’Estrange, Abstemius’s Fables, Fable CCCXIII, Quote Page 274 and 275, Printed for R. Sare, T. Sawbridge, B. Took, M. Gillyflower, A. & J. Churchil, and J. Hindmarsh, London.
RonAKA RebDovid
Posted
My wife did enough research on hip replacement options that she knew about ceramic on ceramic versions. When she asked the surgeon about them, the surgeon agreed to use them.
Guest aaron15970
Edited
aaron15970
Posted
Thank you so much for the help, everyone! Looks like I've got more reading to do 😃
aaron15970
Posted
Actually, another quick question. Looking at the defocus curve of monofocals, there's a steep drop-off. What does that tend to translate to in real life situations? Assuming it's set to distance, does vision become amazingly blurry suddenly at the approx 1 meter mark? Would it be possible to see a computer screen that's at your outstretched fingertips, for example (in the average case)?
RonAKA aaron15970
Edited
I just tried reading your post with my distance eye while my finger was touching the screen (24" size monitor). I can read it, but it would not be comfortable to do computer work at that distance with that vision. And no, vision does not drop off a cliff. It just gets fuzzier and fuzzier until it would be very difficult to read. I can read text down to about 12" with the distance eye, but it is a struggle. That said my near vision seems to be better than what some get with a distance monofocal.
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Keep in mind that IOL near vision is very light dependent. Black text on white screen is quit bright and easier to read. The pupil closes down and increases depth of focus. White text on a black background is much harder. So is reading a paper document in dim light, compared to reading in full sunlight.
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However with monovision I just keep both eyes open and everything is much more comfortable at 12-14" in reading a computer screen. The vision is mainly coming from the close eye (about -1.6 D), but I don't notice which eye is giving me the vision. The brain is very good at picking the best image and using that one.
aaron15970 RonAKA
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That really helps me visualize, thanks. Would you say the distance eye adds anything to the near eye in terms of acuity? Or would you say the near eye is carrying essentially the whole load of intermediate to near? Just curious. Right now my cataract eye is totally out-of-focus, so I'm getting a real life idea of what essentially seeing life through one eye is like. Not sure what, if anything, my bad eye is bringing to the table. Even if blurry, is there still a summing effect between the two eyes?
My cataract is in my non-dominant eye and I've basically decided that will be my "near" eye. I'll either do a vivity set slightly myopic or a monofocal set to near. With that determined, I need to look to the future and decide what to do with my good eye to maintain a good glasses independence/quality of vision combo between both eyes (when the time comes; my good eye is still clear at all distances).
So these questions here are about what to do with my good eye when a cataract comes calling. I'll want to have that one for distance and I like the idea of the great vision quality/contrast of a distance set monofocal. I'm curious about how my two eyes might work together (after the cataract eye is set to "near"). Seeing as my other eye is still good, I'm trying to visualize what setting it to best distance with a monofocal would mean in real world terms.
RonAKA aaron15970
Posted
What is your eyeglass prescription for the non cataract eye? That is going to impact how well the eyes work together without glasses after you have cataract surgery. At your young age that may likely be a long time. If you have near plano vision in the good eye, then doing the cataract eye for near should work well.
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FWIW it is not essential to have the non dominant eye as your near eye. I actually have the reverse which is called crossed monovision. Some actually believe it works better that way. I am not sure as I have no way to compare to the other way now.
RonAKA aaron15970
Posted
It is hard to tell how much the distance eye adds when looking at the computer screen with both eyes at 14" or so. It seems more natural with both eyes open, but not much difference in vision. Suspect near eye is giving 90% of the visual acuity.
aaron15970 RonAKA
Posted
I was myopic and wore contacts the majority of my life. My eyes were not equally mypoic. My left eye (the one that has the cataract) was -5D and my "good" eye was -3D at the time I got lasik (a few years ago). Both eyes have been plano since then. I should note that the same surgeon that did my lasik will be doing my cataract surgery.
Since the cataract developed, my left eye has been almost totally out of focus at all distances, while my right eye is good at all distances (though I have noticed that I could probably use a weak weak reader for small text in lower light at night; I noticed this for a couple years and assume it's because I'm over 40).
So I still see good at all distances today without correction. The good eye is clearly shouldering that load 99% since the other eye is like looking through highly frosted glass at all distances.
When you say "both eyes at 14" or so", do you mean both eyes looking at something 14" from your face? If I went for the vivty in the cataract eye and have that very slightly myopic (which is what I'm currently leaning toward), and then a monofocal in the good eye set to plano, that would probably cover the bases in a way I'd be most happy with (for my wants/needs). I guess I'm just curious how that configuration would "feel" lol. Not easy to describe, I would imagine. I would think that with both eyes, I'd get good depth perception between both the eyes up to about the range the monofocal blurs out but still get clear intermediate and near even if 90% of the work is being done by the near set vivity eye. Heck, both eyes would be way closer to each other and working way better together than they do now.
I'm lucky that I can mull some options for the good eye since it might be awhile before I have to make the call on the non-cataract crippled eye. This first cataract really put me on the back-foot and I'd like to nail down a plan for the future.
RonAKA aaron15970
Posted
"When you say "both eyes at 14" or so", do you mean both eyes looking at something 14" from your face?"
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Yes, and specifically looking at the computer screen. I don't see better or worse with both eyes open, but I do seem to see a wider field of view with both eyes open. It is probably a peripheral vision thing where I am seeing more but not real clearly, but if there is something of interest, my close eye looks over to see it more clearly.
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When I was making this decision, I had already had the first eye done with a monofocal, and had excellent distance vision. When it came time for the second eye it came down to two choices. The one I was favouring was a Vivity at -1.0 D, with the other choice being a monofocal (Clareon) at -1.5 D. I had gone 18 months or so with only one eye done and had been simulating the monovision with contacts. So I was comfortable with the -1.5 D monofocal, but had no way of simulating the Vivity option. When I had the discussion with the ophthalmologist he discouraged me from going with the Vivity option (although he would have got another $2,200 for it). I think he had me slotted as a perfectionist, and he said he had another patient that had similar expectations to me and went with the Vivity and was not happy. I suspect he did not want to have another unhappy patient to deal with.
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I have not regretted the choice of a monofocal. I do regret not getting a toric however. I think I left some better vision on the table with that decision.
aaron15970 RonAKA
Posted
"I don't see better or worse with both eyes open, but I do seem to see a wider field of view with both eyes open. It is probably a peripheral vision thing where I am seeing more but not real clearly" --That's an interesting point. That makes a lot of sense. No additional clarity, so-to-speak, is being added but it might feel like there is simply because you're seeing "more".
I'll definitely be doing the toric version for both eyes. I don't like burning money but it's definitely worth it for my eyes and the toric looks to have great outcomes.
Though I changed my mind on the panoptix (too many downsides and poor outcomes) I did ask my surgeon about it. He flat out refuses to implant them unless in very specific circumstances (and mine would not be one of those according to him). He did say that for what I described as my wants/needs that monofocal monovision or vivity micromonovision or a mix and match of both had good outcomes in his practice. This is an agonizing decision but I had decided to go with the vivity (targeted slightly myopic) as the IOL I'll take for the cataract eye. It's a risk but a one I feel alright about taking. Plus the cataract eye has always been my worse eye through my entire life, so I weirdly feel better about taking the chance with that eye than my good eye.
I'm certain I'll go for a toric monofocal for the good eye when the time comes. I'm trying to visualize the vision limitations I'll have in that monofocal eye set for distance. It will certainly be superior in terms of visual quality, which will be fantastic; I just wish there was some way to visualize approx. where and how badly the intermeidate and near vision will crap out lol. Just so I can spend the next couple years "making peace" with the idea, so to speak.
I'll be sure to comment on how the vivity in the cataract eye performs when I have the surgery on Monday to hopefully help anyone that is going through the same thing.
RonAKA aaron15970
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The issue I see with the Vivity at -0.5 D for the near eye is that I think it will leave you short of having good reading vision. And, there is no way of making up for it with the second eye when that time comes unless you are willing to go for the PanOptix or Synergy. I think the cleaner, and more predictable way of getting close vision is to go with -1.5 D with a Clareon Toric monofocal in the near eye, and then with the same thing down the road for the distance eye, except with a target of -0.25 D.