Eyhance Defocus Curve and Landing Zone

@greg59 @Myope_PSC how are your insights here, Greg is targeted further away from plano.

I agree that -0.25 D is the correct target for distance in an Eyhance lens or a monofocal. Yes, you give up a slight amount of distance vision, and the loss will be the same at distance as if you end up at +0.25 D. However the big difference is in close vision. If you end up at +0.25 D the whole curve shifts to the left and you give up 0.5 D of close vision compared to being at -0.25 D. I don't agree with targeting -0.5 D as some do. That is too much loss of distance vision for my priorities. I know I would not be happy with 20/25 distance vision.

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I am not so sure there is any concern about things being unstable in varying light conditions, but I don't play video games.

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My thoughts would be to try contact lenses to give you varying amounts of monovision before jumping in. That will give you a more realistic idea as to what it would be like than just looking at the theory of it. I doubt that mini-monovision would have much impact on on the frisbee golf activity. Less sure about the VR as I don't do that. VR might require glasses to get the close vision as I assume it requires sharp close vision in both eyes.

Generally VR headsets should be fine with monofocals as they usually target 1-2 meter focal distance or are sharp to 'infinity', but they use fresnel lenses so that's another question mark for these implants because of their optics. There are some reddit posts where people say they see close 'normally' in VR.

What's more interesting to me is the variable lens power that moves along with the iris with these things if they have any actual real-life impact to anything. It would truly suck to wear glasses and then your near vision would fluctuate between fuzzy and visible when you watch things that are sometimes bright, sometimes not.

I am afraid I do not totally understand the VR technology. But in the 1-2 meter range both the near eye and distance eye in a mini-monovision configuration should be just fine. The proof would be in simulating it with contacts.

I saw a conversation from some years ago on reddit where someone said "eyhance needs a low cylinder eye", can you help decrypt this for me, please. What's the practical implication? <edit> i reached the person and even he doesn't know what he meant anymore. Probably 3 years ago there was less experience and information about this lens.

A low cylinder eye would be one with low astigmatism. I looked at the spec sheet for the Eyhance Toric II lens and I see it provides cylinder corrections at the IOL plane of 1.5 D to 6.0 D. The effectiveness at the corneal plane which is where the outcome is commonly expressed is lower than that, with a range of 1.03 D to 4.11 D. So at the low end you would need 1.0 D of astigmatism before a minimum power Eyhance toric could be used.

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In comparison the AcrySof IQ and enVista lenses, go one step lower and have a minimum IOL plane power of 1.0 D and effective corneal power of 0.75 D. They would be more appropriate for someone who have the lowest level of astigmatism in the 0.75 to 1.0 D range. You don't want to over correct astigmatism as it flips the axis by 90 degrees. My optometrist tells me that one can react badly to that. They prefer to leave the eye under corrected.

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You should be able to find the spec sheet by googling this:

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Tecnis Eyhance Toric II IOL spec sheet

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You may have to say you are a US doctor to get in...

whats your worry about the funky optics?

There's a couple of big things

1. the fact that the power is altered when your iris opens and closes, which means the iol isn't necessarily "stable", does this impact the use of glasses or have any side-effects? Especially that discussion earlier about hyperopic shift when the pupil opens in low light. What's the magnitude of that shift? Is it so miniscule it doesn't matter or are we talking about significant changes that would have issues say getting stable view using glasses if the lighting changes.

2. getting those glasses when they are needed. I suppose people have been able to get them just fine. Maybe i'm over-reacting based on things Ron has said about them. People have reported they can get a pin-sharp image using these lenses, which is what i want, even if there's a compromise vs. the zcb00.

I've been reading maybe too much on these things that made me somewhat fear these non-monofocal lenses because ultimately you don't know if you like the subjective experience you get from them and it's a life decision.

1. I doubt if altering the power of the lens as the radius increases makes anything unstable. It will just stretch out the focus point of the light. If you google "aspheric vs spherical lenses" and click on images you will get some illustrations of what a precise focus point is vs a smeared/stretched one. Now an Eyhance is not as simple as being a spherical lens, but the impact on the focus point is similar. The focus point is stretched. This increases depth of focus, but at the same time reduces visual acuity. If there is a disadvantage to the Eyhance design it might be that you only get the increased depth of focus in dimmer light when the pupil opens up.
2. Glasses are virtually always going to make the image sharper as it is a trial and error process. You tell the optometrist what you like. The issue with the Eyhance or other extended depth of focus lenses is that there will not be such a sharp clear focus point as the image is stretched. You might have a hard time telling them which correction power is best. And, of course the obvious. The eyeglass lens is only set to one power for distance, and the Eyhance has a varying power. These issues may only be somewhat theoretical. I suspect the eyeglasses vision test likely is bright enough that it has the pupils closed down. If that is the case then you will be just correcting for the power in the middle of the IOL. The softness in the image will then only be noticed possibly when the pupil opens up.

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   The bottom line is that the benefits and side effects are pretty minor with the Eyhance as it does not stretch the focus point very much. The benefits are also pretty minor compared to using mini-monovision with monofocals.

As far as I've understood is that the eyhance isn't a traditional spherical lens but it still has some kind of a "modified" aspherical backside?

That probably has some kind of an impact on the overall visual profile of the lens i would imagine that limits the impact of the spherical surface?

But it's clear that spherical surfaces degrade overall sharpness. I may still just cancel the eyhance appointment potentially and get the standard monofocals ultimately. I've gone full circle with these lenses pretty soon.

There's a write-up from 2019 "Presbyopic Lenses: Evidence, Masquerade News, and Fake News" that's a real grounder with these things also.

The manufacturers play little games with this aspect of the lens. They do things like say one surface is aspherical but then the other surface is not, so in total the lens is not aspherical. Yes, as I said the Eyhance is not spherical, but it is not aspherical either. One would hope it is more sophisticated than a simple spherical lens. That said a simple spherical lens has more depth of focus than an aspherical one. To my knowledge the only common true aspherical lens is the Tecnis 1. On a theoretical basis it corrects all of the average positive asphericity (+0.27) that a natural eye has with a built in -0.27 asphericity. One of course does not know if you have an average eye or not, unless you have it measured and that is not commonly done. The AcrySof IQ and Clareon correct a little less than that with I recall -0.20 SA, leaving you with some positive asphericity. They claim this is based on a study of air force pilots that had natural super vision. They found this group had an average of about +0.10 positive asphericity, and they have designed their lens to approximate that. Bausch & Lomb have taken a bit different approach and design the enVista lens with no negative correction, so leaving you with +0.27 SA. They call it neutral asphericity and claim at a small cost in visual acuity this gives a significantly increased depth of focus, and makes the lens more tolerable to being located off centre in the eye. There may be some merit to their approach. And last there is the spherical lens which leaves you with even more positive asphericity, I think around +0.37. It has more depth of focus but even more loss of visual acuity. However it is not a disaster as prior to the introduction of aspherical lenses that was the standard lens. I think that happened perhaps 15 years ago. At the time there were big arguments about whether an aspherical lens was really worth it.

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And now the funny part is that we are willing to pay extra for a non aspheric lens! Although, I don't think B+L charges a premium for the enVista.

I really don't know what to do here,

I do prefer to get a bump in the intermediate because it's a quality of life improvement to be able to function better when the loss of vision isn't as steep as an aspherical monofocal. Even if the intermediate it's not nearly as "sharp" in the terms you have with a normal eye with 100% accommodation it can provide useful vision compared to no vision.

But I also don't want to sacrifice too much sharpness in the point of highest acuity, because you can move that around using glasses. Now HOW unsharp the image is, it's really hard to say. How one perceives such sharpness is a very subjective issue. Lenses can be objectively / mathematically measured but when you put them inside the eyeball many things come to play. Obviously if these lenses are bad, they wouldn't survive this long in the market necessarily as they would be rejected by patients. I've seen many people report that they are getting a sharp vision with the eyhance. Many older people who go to the doctor to get rid of their bad cataracts are seemingly delighted for pretty much anything decent so it's not necessarily a good measure of quality either and finding younger folks like myself in a similar situation is harder.

Absolutely all experiences with IOLs are anecdotal, even the scientific studies since they're just based on questionnaires and controlled measurements but they tend to be very narrow use cases.

So ZCB00 is exceptionally sharp, but at the price of plummeting near vision and narrow depth of focus. ICB00 could still be a good compromise if it provides you a point of sharp vision. But like you said, getting customized glasses will also have challenges if you can't get a good measurement. How bad that issue is I can't really say. Standard readers probably work perfectly fine at that single focus point you get, the ZCB00 is even more unforgiving for depth of field. I'm sure there are glasses that provide a continuous vision from near to intermediate also.

It's important to go through this process so that the decision you make is an informed one, because companies are good at marketing the positives but always tend to leave out what you pay for the benefits. The more I learn (also here) the more scared I am of choosing anything but a simple predictable monofocal lens. The marketing is strong. It seems like those Korean "studies" are likely all part of the marketing, because they're so clearly too good to be true for what this thing is. They have USAF target images that are brighter and significantly better with the Eyhance.

The mind games this process of discovery plays to someone like me, who has otherwise great vision at all distances for my age aside from the cataracts is really something else. At some point I was thinking that even people reporting good things about this lens online are just actors, and the surgeon is in on it but that's silly and I know it is silly. But my brain went through these things. The loss of my excellent accommodation and almost full range of vision causes true grief and emotion. There are many scenarios where glasses are not practical, like going swimming or going out in bad weather.

Maybe we are still discussing ultimately relatively minor issues with the Eyhance and I'm throwing away an opportunity have an improvement in my vision range with minimal costs. The fact that these are untestable products make this issue worse.

Have look back at the defocus curves in my initial post. Defocus curves are not just subjective opinions if they are done properly. They are done with a fairly large number of subjects that are fully corrected to 0.0 D plano. They then hold a -0.5, -1.0, -1.5, etc lens in front of the eye, and test the vision at each point. That is where the curves come from and why they have a horizontal defocus scale in diopters.

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If you look at those curves I posted the Tecnis 1 does not really drop off a cliff, and the Eyhance in comparison is not all that much flatter. At the 0.2 LogMAR line the improvement from the Tecnis 1 is from -1.0 to -1.3 D. That is from 40" to 30", or an improvement of 10". If you offset one Tecnis 1 lens by as little as 0.3 D you get the same result. That is the impact of offsetting the lens powers. I would do much more and offset by 1.25 D, but as you can see it does not take much to get the same effect as the Eyhance. Offsetting by small amounts is not going to get you into the comfortable reading range, but it easily matches the Eyhance.

The surgeon is planning to offset the lens by -0.25 and assuming she hits that target the tecnis1 has a for sure noticeably lesser compromise in distance because you are still left with slightly over 0.0 logmar at 0, and the 0.2 logmar line in monocular will be at -1.25 while the eyhance provides a further boost to the intermediate at -1.5 and has a higher MTF curve there in lower light, (how much the hyperopic shift is in dark, i can't say)

Considering i spend most of my time in front of a computer and close proximity activities etc. then it may still be worth that bump for intermediate with the Eyhance, but my distance will be left just barely below 0.0 logmar, which isn't completely terrible. My distance is likely worse right now because of the cataracts even if my right eye is slightly hyperopic.

With that offset the monocular acuity at -1.5 will be 0.2 logmar, binocular likely even better. If i choose to do do a similar target on both eyes then it will still provide pretty good vision to intermediate without compromising distance too much and without doing any monovision (that's, again assuming the target is met).

Glasses near are a requirement in any scenario for comfortable computer work etc but if the intermediate vision is acceptable then that maybe a worth-while. The difference isn't huge, but noticeable in the near vision where the difference in clarity between ~80 and 66 cm is already noticeable. I can see my family across the smallish dinner table with reasonable clarity without glasses if the lights are adequate and I can reach to my golf discs at arms length and see what they are.

The question ofc remains how the distance vision will ultimately look like with the eyhance offset at -0.25. Both sides of the equation can be fixed with glasses, but it's nice to not need them at arms length most of the time.

I suppose one limiting factor is that these iols only go in 0.5d increments, how does the surgeon manage the in-betweens?

When I say offset, I am talking about an offset between the lenses. You could essentially match Eyhance by targeting -0.25 D in your dominant eye with a Tecnis 1, and another Tecnis 1 in the other eye at -0.50 D.

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I don't use glasses for computer work. Progressives work but they are not as comfortable as no glasses with my mini-monovision.

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A 0.5 D step in an IOL is essentially equal to 0.35 D at the cornea or eyeglass level. When you get your eyes measured and the surgeon has the data in the computer they can target whatever you want in even steps of diopters. The computer will come back and recommend a power plus display what the step above and below that power will result in. For that reason you need to target a range, not a specific even 0.25 D step. A normal distance target would be to land between -0.25 D and 0.0 D.

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If you can still see well I think you could answer a lot of your questions and concerns with a trial using various powers of contacts. Accommodation will impact the impression some, but that can be compensated for.

You may be interested in seeing what the surgeon works with to determine the power of lens is needed based on your eye measurements. Google this:

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IOLMaster 700 Quick Guide Printing Functions EN PDF

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See PDF page 5 for the basic form. It includes the eye measurements, the target, the lens, and the predicition formula... You should ask for a copy of this sheet and you should also have a discussion with the surgeon on the final power selection. There almost always will be a choice between two powers.

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Notice in the hypothetical example they use one eye targeted to -0.25 and the other to plano.

I know you constantly keep advocating for monovision for pretty much everyone in every conversation, but It's not something I want to do, even with the cost of using glasses. It's just 100% off the table. So It's not helpful to keep talking about it.

Also, i've never used contacts in my entire life so it's a hurdle to go out and start playing around with them just to try out if i like monovision or not. I can try it once the first iol's been installed if it's a thing for me.

I'd rather have a very good parity with my eyes like I've had all my life so i can keep both my eyes in matching focus. I know my brains will adapt, but my wife has head aches and migraines because she has natural monovision.

I'm only interested in trying to figure out if the benefits of visual acuity / sharpness with monofocals are the loss of visual acuity / other quirks of eyhance to help gain vision at arms reach, which is a pretty good perk to have.

To be able to see your phone by just extending your arms. Or deal with your meds at arms length even if it's fuzzy closer is 100% less debilitating than being forced to find your readers in order to see which meds you're taking.

Sure monovision can help, but i just don't want it.

^ are worth the loss of ^

So to just repeat, while the difference between the gain of eyhance vs tecnis1 is a difference of perhaps 10 inches of extra clarity at logmar 0.2 at arms lenght is actually a pretty big deal if you don't have glasses nearby.

This is obviously in the event that you get the result of that theoretical focus curve. It's hard to predict.

That is fine. Monovision is only an option. I mention it because many surgeons do not. Seems to me one should be aware of the alternatives. I find many here come looking for a "technology/price" solution while overlooking a simple configuration solution.

FWIW, here is the Eyhance description in a review article of various EDOF and near-EDOF IOLs published in the January-February 2023 issue of the Asia-Pacific Journal of Ophthalmology, available on line by searching for Latest Developments in Extended Depth-of- Focus Introcular Lenses: An Update. (They also have a lengthier description of the Vivity.)

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EyHance ICB00 Tecnis lens (Johnson & Johnson Vision): EyHance IOL is merchandized as enhanced monofocal IOL though it offers a smooth and continuous progression of its power from periphery to the center, with no demarcation line (Fig. 24). It aims to present the distance performance and minimum photic effects of the monofocal (ZCB00) while compensating for SAs in the cornea and providing intermediate vision at 66 cm. It is a single-piece, hydrophobic-acrylic IOL with a 360-degree posterior square edge and a tiny central plateau and thus a local change in power is applied to EyHance IOL to enable a local refractive change, whereas the basic anterior curvature is aberration correcting with negative primary SA. Clinically it leads to an improvement in intermediate distance vision when compared with monofocal IOLs. Regarding defocus, measurements indicate that the TECNIS EyHance IOL has a larger “landing zone” than the TECNIS Monofocal IOL and provides excellent (0.0 logMar) distance vision. The lens is pupil-dependent. No information is given about modified SA by the manufacturer. In a laboratory investigation of visual quality metrics and halo size by Auffarth et al, it was demonstrated that the mono-EDOF models had a clear advantage over the standard monofocal lens by expanded imaging capability beyond −0.50 D and that the ICB00’s halo profile was similar to that of the ZCB00, indicating their low potential to induce photic phenomena.

On the web, I found seven Eyhance defocus curves. As an indicative, not predictive, exercise in thinking about my own impending cataract surgeries, I averaged the data at different targets, e.g., plano (0.0), -0.25D, etc. and (LogMAR) distances. For what it's worth, assuming the surgeon hits the target in both eyes the mean LogMAR result would be 0.2 or better, as follows:

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0.0D: +0.50D (0.095) to 26.25" (0.205)

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-0.25D: +0.50D (0.103) to between 26.25" (0.161) and 19.69" (0.231)

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-0.50: +0.50D (0.177) to between 26.25" (0.121) and 19.69" (0.216)

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-0.75: 0.0 (0.103) to 19.69" (0.19)

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-1.0: 0.0 (0.2) to 15.75" (0.1971)

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Bear in mind that the data themselves are averages with standard deviations. Even if the data are entirely accurate, the subjects of the studies perfectly representative, and my eyeballing of the defocus curves also entirely accurate, your result could vary. But I think pooling data provides a better picture than just using one defocus curve, especially if it comes from the manufacturer.

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If you want to look at my sources (perhaps check my arithmetic), here they are. BTW, I did not use the defocus curve in the Korean Journal of Opthalmology because it seemed anomalous to me that, across-the-board, the Eyhance curve should be better than the Tecnis 1 curve.

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Comparison of an aspheric monofocal intraocular lens with the new generation monofocal lens using defocus curve, Yangzes S, Kamble N, Grewal S, et al., Indian J Ophthalmol 2020;68:12:3025-9. (This is the source of the defocus curves in the "Newcomers" article that Ron has cited.)

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The Evaluation of a New IOL with Extended Depth of Focus to Increase Visual Acuity for Intermediate Distance, Fikret Ucar and Servet Cetinkaya, SN Clinical Comprehensive Clinical Medicine (Nov. 2021) (Although the full text of the article was not available to me, the defocus curves are included with the abstract available at ResearchGate.)

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Clinical evaluation of a new monofocal IOL with enhanced intermediate function in patients with cataract, Gerd U. Auffarth, MD, PhD, FEBO, Matthias Gerl, MD, Linda Tsai, MPH, D. Priya Janakiraman, OD, FAAO, Beth Jackson, PhD, Aixa Alarcon, PhD, H. Burkhard Dick, MD, PhD, FEBOS-CR, Quantum Study Group, Journal of Cataract & Refractive Surgery 47(2):p 184-191, February 2021

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Visual Acuity, Wavefront Aberrations, and Defocus Curves With an Enhanced Monofocal and a Monofocal Intraocular Lens: A Prospective, Randomized Study, Mayank A. Nanavaty, MBBS, DO, PhD; Zahra Ashena, MD; Sean Gallagher, BMedSci; Steven Borkum, DipOptom (SA); Paul Frattaroli, MA (Hons), MA (Post-Grad); Emma Barbon, BSc, Journal of Refractive Surgery, Vol. 38, No. 1, 2022

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Comparison Between an Intraocular Lens With Extended Depth of

Focus (Tecnis Symfony ZXR00) and a New Monofocal Intraocular

Lens With Enhanced Intermediate Vision (Tecnis Eyhance ICB00), Young Joon Jeon, MD, Yisang Yoon, MD, Tae-im Kim, MD, PhDy, and Kyungmin Koh, MD, PhD, Asia Pacific Journal of Ophthalmology (Phila) 2021; 10:542-547

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Visual outcomes, spectacle independence, and patient satisfaction of pseudophakic mini‑monovision using a new monofocal intraocular lens, Ella SeoYeon Park, Hyunmin Ahn, Sung Uk Han, Ikhyun Jun, Kyoung Yul Seo, Eung Kweon Kim & Tae‑im Kim, Scientific Reports (2022) 12:21716

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Delivering Intermediate Vision: The New TECNIS Eyhance Monofocal IOL (sponsored by Johnson & Johnson Vision) April 3, 2019.

Thanks,

i've also scoured the net through all kinds of articles, and while you can see logmar 0.0 it doesn't automatically mean that it's "sharp", just that you can read the line. There's a lot of terminology in lens characteristics like Z4 and J45 etc. that i don't quite understand in laymen terms. One concern that has been raised multiple times by RonAKA that because of the power change through the lens it maybe difficult to get a matching set of advanced prescription glasses, as you likely need them.

When i'm used to having great vision and accommodation at all ranges all my life and close to 0 prescription in my eyes everything will be a downgrade. Presbyopia is also extremely mild, i have a friend about the same age and his presbyopia is quite extreme already. Genetics i'm sure.

Ultimately what would really help is some lengthy chat with someone with a similar eyes than myself with these things implanted to understand what the vision looks like first hand and if it's truly sharp at the peak acuity. Being an engineer that does a lot of research before making any choices I maybe so demanding with my vision that i may not be satisfied with subpar outcome even if the lens has other redeeming factors. Fixable trade-offs are fine, unfixable are not.

If you read this article right near the end, there are some suggestions on how eyeglasses should be set for the Eyhance lens with Maximum Plus Refraction.

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orthopticscpd Unaided Intermediate Vision: A Paradigm Shift in Cataract Surgery? DR JAY YOHENDRAN 1ST MAY 2020

Johnson & Johnson's post operative instructions to professionals for refracting eyes with Eyhance IOLs can be found on page 10 of their Getting Started Guide, which can be found at the JnJ Vision website: eduction center / resource library / IOLs and implants.

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In addition to describing how they suggest doing the maximum plus refraction, the guide says: "Due to the elongated focus of the TECNIS Eyhance®, refraction needs to be performed with care using the maximum plus refraction technique (“pushing

plus”). This refractive outcome will be used to refine your personal lens constant."

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I recall that at least one person has expressed concern about the difficulty patients may have deciding which of two choices is the better view. All I can say is that my wife, when she was refracted following surgery on her second Eyhance eye, seemed to be much more decisive than I was last week when an optometrist refracted my natural eyes to prescribe contact lenses so that I can try out mini-monovision.

She seems to be happy with the lenses then. Would it be possible for her to describe what her visual experience is and does she get sharp vision using the lens?

sharp should be defined as: hd quality video on phone. details of the lines on the hands and oores on the skin, threading a needle and details of am embroidered cloth.

Sharp == everything in the focus point looks like it's 'perfect' definition without any distortion and blur. Obviously eyes aren't perfect, but if you can make out the smaller detail without feeling it's not in perfect focus (does not feel like it should be improved with some correction) it should be pretty good. This is difficult to quantify objectively from people's personal experiences.