Eyhance Defocus Curve and Landing Zone

If you have both a monofocal and Eyhance targeted to -1.0, I think that will leave you short on reading ability. You might just get away with it, but reading is not likely to be crisp. Intermediate should be fine though. The Eyhance will behave much like a monofocal targeted to -1.3 D. My experience is that -1.5 D with a monofocal is the sweet spot for reading and intermediate.

If intermediate is most important, you may want to do that eye first and see if you get a good result. If not, try again with the 2nd eye. Essentially, that's what I did but had to wait 5 weeks between eyes.

Looks like your doc's plan, if achieved without problems could give you functional vision at a wide range of distances, especially very close up. Not much binocular vision but driving without glasses at 20/30 or so seems possible. Functional vision at 9 inches throughout the intermediate range with the Eyhance set at -2D. Pill bottles would likely be readable. Close up work on electronics and fixing small items is likely possible without magnification.

If I'd been willing to do more monovision, I would have considered that a good plan.

I have readers that put me at -1.00 & -1.10 and some that put me at -0.5 & -1.375. (spherical equivalents) The -1.00 & -1.10 readers are my preferred computer glasses.

In good light, the -1.00 & -1.10 readers are better at 1', 3' & 4'. The -0.5 & -1.375 readers are better from 5' and beyond. At 2' it's basically the same with either pair as I don't see a difference between them. It's interesting to me that the -1.00 & -1.10 pair seem better to me at 1'. It must be a bit of suppression vs summation going on then and my brain can combine the more similar images better. I don't think either pair would work as well for reading a phone in bed compared to -2.00 or -2.50 readers.

You should be able to get a good idea though of of what combo works best for you using your Trial Frame & Lenses.

jimluck - Remember that Eyhance will essentially get a +0.5add in low light situations. Ron is right about -1D Eyhance not being sufficient for reading. I had problems reading intermediate screens in low light with my -0.9D IOL. With the +0.5add, I was seeing more like -0.4D and the screen at about 30 inches (1.3D) was just slightly out of reach in lower light. I had to set the fonts bigger and zoom in to read.

My newer IOL was set closer to -1.3D and screens are now easily readable in all lighting. In low light, I use the near eye and in bright light I use the far eye. After I get off the drops, the near eye might take over all intermediate duties but for now that's how I see screens.

I wonder how transferable your experience is to another set of eyes. Is 1d of undercorrection in an IOL the same for eveyone?

I know that for me, in glasses, 0.75d to 1d of undercorrection is plenty for the computer, with vision being best at 21 inches. Will that still be true for me after cataract surgery? Or will I then need more undercorrection, like you do?

Clearly my optometrist thinks more add is necessary. She prescribed add of 2.75 last year, then this year, after I complained, backed it off to 2.25. When I got the new progressives with 2.25 add, I sent them back after a month and told them to take the add down to 1.00 (just got the new progressive back -- much better with the lower add).

My experience likely only applies to the Eyhance because of its design that varies power from the edge to the center of the lens and overall flatter defocus curve. I'll see the optometrist on Thursday for my first post-surgery visit on the 2nd eye. Right now, I'm expecting to see very close to 20/20 at distance even with the near eye targeted for -1.3D. I should find out how the achieved focus point at the appointment but I can see just a bit better at near so I'm expecting a result within +- 0.2D of the target. Probably J2 or better near using binocular vision. But those tests will be done under ideal conditions for the Eyhance. Driving in bright sun is maybe 20/25 or 20/30. The issues I had with screens in poor lighting are getting better but I'll know more tomorrow when I return to the computer lab.

Perhaps my pupils and cornea spherical aberrations are a good match for Eyhance and that explains my better than expected results. Maybe I've avoided residual astigmatism with the limbal relaxing incisions thus far....but that could change in coming months.

I suppose I could have chosen targets closer to plano and maybe my distance vision would be a sharp 20/15. But I'd have given up my near vision in average light and perhaps low-light intermediate so I would have been walking around with readers. So far, I've not purchased any readers and am only frustrated when reading the smallest print in low-light.

I'm happy with the choices I made for targeting Eyhance. I don't think my -1D and -1.3D targets would have worked as well with Vivity or standard monofocals though. Distance vision with the monofocals would likely have been a bit worse but still driveable. Near vision would likely have also been just a bit worse in most lighting. However, the monofocal at -1D would have been better in low light intermediate where I was struggling monocularly with Eyhance. It has a higher peak defocus curve at the target focus distance. With Vivity, pulling the relatively short defocus curve peak toward myopia would likely have caused the night driving / contrast sensitivity issues at distance warned about in their inserts. It seems to be designed for plano targeting.

Thanks. I'm trying to get at a different, but related issue.

What you are saying about targets and results makes sense in the context of the standard charts and formulas. What I experience with glasses of various powers does not. 0.75d undercorrection in glasses is sharp for me at 12 to 28 inches, with 21 inches being the peak.

Is it that glasses undercorrection is different from IOL undercorrection? Or are my eyes just weird? I think it must be the latter.

Did you experiment with various amounts of undercorrection using glasses and lenses and if so, were the results indicative of what you now experience with your IOL undercorrection?

When I had one eye with an IOL and one with a minor cataract natural lens I did some testing with readers and contacts. What I found is that with the natural lens -1.25 D seemed to be optimum. However, with the IOL and my natural lens accommodation gone, then -1.5 D was better. So there is some difference when comparing a non IOL eye to an IOL eye due to accommodation.

My doc says we could do the experiment after administering eyedrops to paralyze the accommodation.

It sounds like you got very good outcomes from the Eyhance surgery.

Well, I had the Tecnis 1 ZCB00 implanted in both eyes that were very myopic and had 2D astigmatism, which I did not correct either with a toric or limbal relaxing incisions. I had planned to correct it with eyeglasses. As it turned out I have 20/20 and 20/30 distance vision and excellent intermediate vision. My near vision is good too. Depending on the font size on a page and the light, I can read without glasses. I only need readers for small print or when the lighting is bad. My night vision is fine. My cataract surgeon was surprised how well I see. She said setting the target for intermediate vision counterbalanced my astigmatism.

I'm happy that I ran across this discussion. Looks like these lenses with some edof logic are definitely more complicated to get right.

I'm 44 and have 'normal' eyes with no irregularities aside from PSC and i'm concerned of the contrast loss in Vivity, but that's probably a pretty critical thing here too if you don't get things right. I suppose regardless of where you end up glasses can shift the power where it's needed, but if you want some level of independence from glasses then getting this right seems to be super important.

That defocus curve that I gave in my original post is one of the few Eyhance curves that looks reasonable and believable. When set with the peak acuity at 0.0 full distance the monofocal distinctly is better. This shows the price paid to get the extension of focus at closer distances. In the hyperopic + zone the Eyhance curve is no flatter than the monofocal curve. So this lens has no more tolerance to be pushed to the minus side than a monofocal. Because the curve is flatter on the minus side there is more tolerance for the surgeon to miss to the plus side when you only consider distance vision. But the real cost of missing on the plus side is in the close vision. Because the curve is flatter there the loss of near vision is greater than with a monofocal. And while it is hard to measure but at the LogMAR cutoff of good vision at 0.2 I only see an extension of near vision of about 0.3 D. That is not a lot. It is one minimum step in the vision scale. If I was to use the Eyhance in a mini-monovision configuration this all confirms to me that the correct targets would be -0.25 D in the dominant eye, and -1.25 D in the non dominant eye.

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But this all said, I still think the advantage of doing that is so small that one would effectively be just as well off with a monofocal at -0.25 D and the other at -1.50 D.

I'm not planning on doing any significant monovision with these things, because I have hobbies that would require good stereo vision like disc golf and VR gaming. It's not even on the table for me.

I need to consult with the surgeon on how we make sure we hit the target well to not cross over hyperopia and avoid wasting any near-vision benefits of this lens. Obviously there's still the option to fine-tune the vision with lasik (it's included in the cost), but ultimately i suppose you'll be wiser once the first lens is in place. LALs would be optimal for safety but they don't have features like this.

Ultimately I will likely glasses regardless to have comfortable computer and near capability, but having a bump in the intermediate vision is helpful for a lot of things.

Obviously the binocular outcomes are better than the monocular ones, but i think your original posting has a very important observation that if you become hyperopic with the eyhance you can be easily worse off than with the regular monofocal.

The thing to keep in mind with Lasik is that they can easily make the cornea less steep (more hyperopic), while it is very difficult to make the cornea more steep (more myopic). If you are going to miss and correct with Lasik you want to end up too myopic, but not hyperopic.

There's an interesting comparison of zcb00 and icb00 with a pretty big sample size (111 icb00 / 86 zcb00) in an article called Visual Performance and Optical Quality after Implantation of a New Generation Monofocal Intraocular Lens, the full text can be found from the ekjo website. The defocus curve on that paper looks ... curious, it's as if the icb00's were set to -0.5.

(but the study says emmetropia was targeted)

is it monocular or binocular defocus curve?

its monocular. but it coincides with what ron is saying which is if vivity is 0.5D, eyhance is 0.4D near.

Those are very misleading curves as they have obviously offset the Eyhance to -0.5 D. That makes the curves not comparable unless you move the whole curve of the Eyhance back 0.5 D. It is hard to do by eye, but it looks to me that if you move the Eyhance curve back it is really not much better than the Tecnis 1 to the right of the peak. And the other suspicious part is that if you move the Eyhance curve back 0.5 D the peak vision at 0.0 D is better than the monofocal Tecnis 1. None of this makes any sense, and I dismiss studies like this as garbage. They defy the laws of physics!

Monocular, the paper doesn't have a binocular curve at all.

One thing to keep in mind that the study was done fully on asian population and they are disproportionally myopic compared to westerners. So there are biases involvedd.

if this defocus curve is true then why not set the eyhance for -0.75 to -1D and get the benefit of 0.1 LogMar for 0 to 1D with peak at 1.5D and decent near?

In advance of meeting with my surgeon, I found six studies containing Eyhance defocus curves that either are freely accessible on the web or were accessible on the web through my library. Although not identical, their results are more-or-less consistent. In my view they support choosing the Eyhance, as my surgeon and I have done, if one wants to good vision with a reduction of spectacle dependence and either no or only modest monovision.

Ron, you've written more than once that you doubt the reasonableness and believability of many (most?) Eyhance defocus curves, but I haven't seen an explanation for your doubts. With my limited imagination, the only one that occurs to me is a belief that the investigators either are incompetent or dishonest, but why I should believe this is unclear.

As an indication, not a prediction, of plausible results with Eyhance IOLs, and recognizing that defocus curves report mean results while any individual's results will fall somewhere along a range above and below the mean, these are the logMAR averages I calculated for the better eye in a mini-monovision configuration with the one eye targeted at -0.5 D--my surgeon's target--and the other eye at -1.25 D:

0.0: 0.095; -0.50: 0.0; -1.00: 0.02; -1.50: 0.03; -2.00: 0.10; -2.50: 0.18; -3.00: 0.21; -3.50: 0.35

For what it's worth, this same surgeon recently implanted Eyhance IOL's in my wife's eyes, both targeted to his standard -0.50 D. Five weeks after surgery, here distance vision tested at 20/25 (which is 0.0969 logMar).

Aiming for these results with a standard monofocal would require more monovision. I don't think there's a universally right or wrong answer.

The studies from which I derived the defocus curve data are:

"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.

"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

"Optical Assessment and Expected Visual Quality of Four Extended Range of Vision Intraocular Lenses", Juan Antonio Azor, MSc; Fidel Vega, PhD; Jesus Armengol, PhD; Maria S. Millan, PhD, Journal of Refractive Surgery, Vol. 38, No. 11, 2022

"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, Youngsub Eom, Seul Ki Yang, Young Choi, Hyo Myung Kim and Jong Suk Song, BMC Ophthalmol, 2021 Oct 16;21(1):365

"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

"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.)

how is your wife's near vision with both eyes at -0.5? and how is your near vision with -1.25 eyhance? how is your distance vision in that eye?

What's your wifes intermediate acuity at -0.5D and how well does the vision hold-up in lower light?

My experience with researchers is that they often report results without stepping back and asking themselves if they look reasonable or not. To me the Eyhance lens is quite simple. They vary the power of the lens with the radius of the lens. This smears the focal point and extends the depth of vision. The price is that peak visual acuity is compromised doing that. For some that may be a good compromise, and I don't dispute that. But when they report that there is no compromise to peak vision then I start to get suspicious. That outcome makes no sense. That is my issue with the Eyhance is that I believe some of the marketing is misleading. The defocus curve based on about 70 individuals with each lens in my initial post looks very reasonable. I would be comfortable basing predicted outcomes on that defocus curve. But I sure would not expect to get the same distance vision with an Eyhance as I would get with a Tecnis 1.

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I think targeting -1.25 D with the Eyhance in the near eye of mini monovision makes very good sense and fits with the defocus curve. It should achieve an effective -1.50 D in the near eye. Targeting -0.5 D in the distant eye makes no sense to me. I don't understand why one would want to give away the best possible distance vision. The normal target is -0.25 D to provide a small factor of safety against going positive and possibly give a little visual acuity away. Unless the surgeon is not very confident in predicting the required power, I think targeting -0.5 D is too much. Some distance vision is being given away already by using an Eyhance instead of a monofocal like the Tecnis 1, so why give away even more? What would make more sense if one insists on using an Eyhance lens is to use it in the near eye only, and use a Tecnis 1 in the distance eye targeted to -0.25 D. That would almost certainly give better distance vision and possibly 20/15 vision. Since the near eye is covering the closer distances there will be essentially nothing lost in near vision. I personally would not be happy with 20/25 distance vision, but I guess some are OK with it. I am just not sure anything is gained by taking that distance vision hit.

Ron

Your analysis is correct. I have had cornea specialists tell me that while they think the Eyhance is an excellent IOL, it has been "overhyped" based on their experience using it.

one observation ive made with my psc is that even if the axis has junk in it, if my iris opens enough to pass light around it i have no severe issues in my vision. obviously the junk is everywhere in the lens now so the vision is definitely compromised. Not sure about the severity of "smearing" in this context.

She is finding readers beneficial for close reading, for example,looking down to papers on her desk, whereas she uses/reads material on her MacBook without glasses.

I haven't had cataract surgery yet. Having decided with my surgeon on EyHance, I'm meeting this week with his practice's optometrist to discuss contacts and trialing different degrees of monovision before making a final decision.

One open question is whether to try before my first surgery or between the first and second. I'm 73. A lifelong myope, my prescription in 2021 was

R -6.25 -0.50 180 Dist VA 20/20 ADD +2.50 Near VA J1+

L -7.50 -1.50 134 Dist VA 20/30 ADD +2.50 Near VA J1+

Because she is less driven than I am to research and put numbers on these matters, all I can say is that she comfortably uses/reads her MacBook without glasses.

"One open question is whether to try before my first surgery or between the first and second. I'm 73."

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I would do both and I did both before and between. The contact between became my 15 hour a day solution until the second eye was done. I am also 73! If you wear contacts before your eye measurements are taken you should check with your surgeon how long before your measurement should they be stopped. They can change the shape of your eye and mess up the measurements. I believe it is 1 week with soft contacts and possibly a month with hard ones.

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You are a fairly high myope and I would be cautious with power calculation. I think that is the biggest risk of a "refractive surprise". It is a good idea to ask your surgeon for the IOLMaster Calculation Sheet. It gives you all the data you need to check what power of lenses are predicted with the various formulas. There calculators are on line and I would suggest the two best ones for a high myope would be the Hill RBF 3.0 and the Barrett Universal II. The calculators include a field to input your desired target for each eye.

Ron: If you are reading studies that claim identical results from the Eyhance and Tecnis 1, then I agree that those studies are over-selling the virtues of the Eyhance. But none of the studies I've found, and provided references for in an earlier post, makes such claims.

Have a look a this one that was posted a little earlier in this thread. Have a look at the defocus curves.

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Visual Performance and Optical Quality after Implantation of a New Generation Monofocal Intraocular Lens

Just looking at the defocus curves, it's the authors' results for the Tecnis 1 that appear anomalous when compared to other studies I've seen, not the results for the Eyhance. At any rate, I suggest you consult the various studies I've cited earlier in this thread. Generally published in more leading journals than this one, they tend to be clear that distance vision and modular transfer function are better at far distance with the Tecnis 1 than with the Eyhance, although the defocus curves often are quite similar.

The problem with that conclusion is that the defocus curve is a measure of visual acuity at the various distances. You can't say that the Tecnis 1 has better distance vision and at the same time say the defocus curves at infinity are the same as Eyhance. Once you get to a closer distance then the visual acuity of the Eyhance becomes better than the Tecnis 1. It is a different shaped curve with a different peak.

The unaddressed question is who is saying the defocus curves at 0.0 D are the same for the Tecnis 1 and the Eyhance? The Korean Journal of Opthalmology article actually reported mean monocular data showing the Eyhance having better visual acuity (logMAR results) than the Tecnis 1 across the board, which, as I noted in my last post, is an anamolous result when compared to the other publicly-available results I've found (and cited earlier). These other studies, from more reputable journals (see below), tend to find similar results at 0.0 D, with the Eyhance's (modest) advantage over the Tecnis 1 emerging by - 0.50 D. Why this is supposed to be unreasonable or defy the laws of physics, I don't understand.

Meanwhile, for whatever it may be worth, according to the Scimajo journal rankings in Ophthalmology, of the journals so far relevant to this discussion, the rankings are:

18 Journal of Refractive Surgery: the Alarcon, Auffarth, Azor, and Nanavatny articles

23 Asia-Pacific Journal of Ophthalmology: the Young article

38 BMC Ophthalmology: the Huh article

46 Indian Journal of Ophthalmology: the Yangzes article (whose defocus curves were reproduced in the "Newcomers" article)

84 Korean Journal of Ophthalmology: the Kyoung article (containing the anomalous relative defocus curves for the Eyance and Tecnis 1).

I was just told at the Herzig that I can't wear my gas permeable contacts within a month of the pre-op assessment. The sheet does have some variables though, depending upon the individual. Here are the guidelines they listed. These are time periods required before the date of the pre-op assessment, not the surgery.

Soft Lenses: 1 week (for me though if I was wearing them, it would be 2 weeks)

Soft Toric Lenses: 2 weeks

Gas Permeable: 3 or 4 weeks (4 weeks was the requirement for me)

Hard Lenses: 8 weeks

The surgeon said I have a long eye and that my macula was thin, but surprisingly healthy (he sounded a little disappointed about that last part, lol).

He was really pushing for mini-monovision with the Eyhance, with the dominant eye targeted for plano, and got a little snippy when I said I didn't want plano in the dominant eye, but that I wanted to target for -1.0D for both eyes.

I've been living for a long time with a version of the mini-monovison you have, and I'm realizing that I'm not going to be happy with that (im)balance any longer. I'm prone to headaches, and right now in particular, with the adjustments (glasses and contacts) made for where that eye is currently stuck at (it's both nearsighted and farsighted) has definitely added to them. Even though my brain has adjusted to that offset, I don't want to have to deal with that "empty" space from that eye anymore -- even though my overall vision is binocular, I'm aware of it. If I need glasses or maybe contacts for sharp long distance, I realize that I'll be okay with that.

One does not have to look at the defocus curves to understand that the Tecnis 1 will have a higher peak visual acuity than the Eyhance. It is all in the physics. The Tecnis 1 fully corrects asphericity to zero with a -0.27 SA correction. The Eyhance varies the lens power over the radius of the lens and simply cannot do that. It deliberately messes up the asphericity to get the extended depth of focus by stretching (smearing) the focal point. There is no free lunch. That compromises the peak visual acuity of the lens. It is no more complicated than that. It does not mater how many studies you look at, the physics do not change.

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As I have mentioned before some think that is an acceptable compromise to get better near vision. My opinion is that there is more to be gained in using a pure monofocal in a mini-monovision configuration than there is to compromising the visual acuity of a lens to get an extension of the depth of focus. But that will depend on the priorities of each individual and what they are willing to compromise on.

I am with the surgeon on targeting plano in the dominant eye, or actually -0.25 D. But, I can't see out of your eyes and I don't totally understand what you are seeing for an "empty" space. I have no sense of any weak distance other than real close, under 10", vision does jam out.

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I think your plan with targeting -1.0 D in both eyes with the Eyhance will give you pretty good closer vision. I would expect you will get away without reading glasses for everything except very small print in dimmer light. However, I think you are going to come up short for good distance vision. The Eyhance lens compromises distance slightly, and in addition you will be a long way off the peak vision point at -1.0 D. I would expect you will need glasses for good distance vision and progressives would be the best choice.

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One compromise you might want to consider is having one eye set to -0.5 D, and the other to -1.0 D. that would be a micro-monovision solution with some compromise to distance vision.

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Oh, and it is a good thing that the surgeon is requiring the discontinuation of the contacts especially since you say they change your eye shape. You want the eye to be fully relaxed and stable before measurements are taken for a solution that should not require contacts after surgery.

I thought about going with -0.5 D in the one eye, but got worried that eye might end up closer to plano after the surgery. I still might ask him for that after they do the pre-op testing, or maybe -0.75 D. I decided to go with the -1.0 D in both, cos I figured post surgery, they weren't going to end up in the same spot anyway, and most likely, like others here (and elsewhere), I would end up with one eye less than the target, and one eye more than it. I was hedging my bets. Also the end results of some others here at that target seemed to work out very well, giving both good near and functional distance. If I do need correction for distance, hopefully only in certain circumstances, thanks to your suggestions about the newer soft lenses, I wouldn't have a problem taking that route. I'd rather try that rather than glasses, as I'd lose peripheral vision which is very good. But if it's glasses, then so be it.

Because of the damage to the left eye, they started backing off the distance vision in it, in both contacts and glasses. Otherwise, I felt almost nauseous when someone, or some thing, was within three feet of me, especially if the target was moving. I still wasn't getting any really clear near vision in that eye with contacts, despite the tweak, and of course distance was somewhat compromised also. Since last year, especially with contacts when my prescription got worse, everything is kinda fuzzy at pretty much at any distance in that eye, creating almost a gap in my vision which I referred to as an "empty" space for that eye cos it's no longer helping the right eye much at all. Although I've gotten pretty much used to this setup prior to last year, and have made it work, I'm worried that by achieving plano in either eye, even with the Eyhance, it might continue, so I'd rather be safe than sorry.

When you first mentioned about me not being able to wear gas perm contacts for a month before the surgery, I thought you were wrong, as I've always been told that the eye regains it's shape after about 3 days, but the surgeon repeated the same, so I stand corrected. And it does make sense considering the differences between what an optometrist test shows versus the in depth testing for this surgery ends up showing.

I think you have thought it through quite well. I think I might plan for a split between eyes in correction rather than just let it happen by chance. But, you are correct we never know for sure exactly where the eye ends up. One strategy to minimize that is to do one eye, find out where it really lands, and then make an adjustment to the second eye target if needed.

Thank you! Trying to decide has been making me somewhat crazy. I've been reading and researching pretty much non stop for the past couple of months, comparing what everyone has done and their outcomes and then comparing it my own situation.

I just realized though that I might not be able to change my mind to use -0.5 D for the one eye after the pre-op. When I called back the next day to set the surgeries up last Friday, I told the person I was talking to that I wanted to do -1.0 D in both eyes (they didn't ask, I decided to bring it up), and she replied something along the lines of "Oh, that will change everything.". I asked her if it was going to complicate things, and she replied, no, just change everything. I didn't know how to bring up "what things" for clarification.

I think I might originally have said I wanted to use the -0.5 D in one eye, but can't remember for sure. My blood sugar was getting low by then, and I was losing focus. I don't want to call back now and say, oh I changed my mind again, lol. Though if the lenses are already calculated to the different dioptometers, you'd think they'd have a variety in stock -- but maybe they have to order them. I will ask after the pre-op and be prepared for some eye rolling.