Near vs. intermediate setting for IOLs

Thanks RonAKA, With regard to the possibility that I might see both near and intermediate with each IOL set to -2.50 and only have to wear glasses for distance and driving, could you describe the range for the intermediate vision? In other words, does that include my computer screen, TV, or throughout the house?

On a related note, is it customary to give a specific target to the surgeon or just something general such as near or intermediate vision?

I am not Ron. But I j told my surgeon to target intermediate vision for my left eye. Three weeks later when it. was time. to do my right eye, my surgeon asked me if I wanted blended vision to give me more near vision. I said no, target my right eye like my left for intermediate. But that was me.

When I think back to when I used +2.5 D readers, I know I could not wear them in the house for general vision. Once I read what I want to read I can't get them off fast enough. Yes you could read paper documents, phone, tablet, and a computer as long as it is not too far away, but I would say no to TV or general things in the house. If there are stairs, I think there would be a risk of falling. One of the things I learned quickly when first getting progressives which bring you to -2.5 D is to not look down when descending stairs. I know that @Bookwoman seems to manage with -2.0 and -2.5 D, but I know I could not do it. That is why I suggested one eye at -1.0. That would open up your view of everything from 1.5 feet out to 15 feet with very good vision in that range.

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I think many surgeons dumb down the discussion by talking near, intermediate, and distance, because most patients do not understand diopters. But the issue is that you never know what their definition of those distances are. I don't think there is even a formal definition. When the surgeon uses the computer to calculate your lens power there is one field where they enter the target. That target is in diopters. So if you can settle on a diopter target then there is no possible confusion as to what that means. And, since lenses come in steps of 0.5 D, there will almost never be an exact outcome of 2.5 D if that is your desired outcome. There will almost be two lens powers with one under and one over that desired target. You should discuss which of the options you would prefer. In fact it is best to think in a range 0.25 D apart. For example 1.0 D to 1.25 D.

Thanks RonAKA,

Could you explain the difference between +2.5 D readers and -2.5 D for IOLs?

They are essentially the same thing. If you ask for an IOL target of -2.5 D you will be -2.5 D myopic. If a person has 20/20 distance plano vision and put on a pair of +2.5 D readers they will be effectively -2.5 D myopic.

I am only having one eye done with EMV since one eye very bad and other eye not ready for surgery . Surgeon said would not touch eye that doesn't need surgey so would set bad eye to keep eyes more or less in balance . And I keep thinking would I want to even do second eye when can wait .

Left eye good eys -3.25 with slight astig so he says think of it as -3.50. Then if we target 1.50 for cataract IOL that would be about 2 between eyes and should be tolerable though I never had monovision contact lens. That concerns me.

Another doctor recommended target -1.25 but that was with eyehance since I once mentioned would like a little more distance but told me the focal point may be at about 29.inches (of course no exact outcome). But that would mean I would have to use good eye to get nearer cataract correction if I want to see computer and not lose too much of my near ability to read without glasses. Then that may rule out using second eye to pick up more distance which would be nice. I am in all visual ranges and that is why so challenging and I wouldn't want to mess around with mulifocals.

Another doc when discussing emv says if -1.25 refracts to 1 maybe a little difficult for diference between eye so he would suggest best to target -1.50 YET by the same token when I said what about target -1.25 or 1 since many go plano and then offset maybe 1 when both eyes ready to be done --he then they says the brain will adapt ( now there would be over 2 diopters between eyes after doing just one eye )and says the fact my eye so bad it is like I am experiencing monovision. And also says he patients seem happier when both eyes more binocular and in same breath people do adapt to monovison.

So my dilmma is do I tell doc to do -1.25 since it is said EMV can extend range maybe up to 1 1/4 diopter of nearer vision in theory or keep the -1.50 though he says not much difference between 1.25 and 1.50. He says with the supposed extended range the -1.50 could potentially that may give me vision up to maybe -2 or -2.25. If that were so and I could see most print accept maybe really small that would open doors for some distance which would be great.

I know in the end with 2 eyes goal I want to be as much glasses free as possible, Know can't have it all but want as much distance as possible. I didn't want to be glasses on and off for reading stuff > I am on computer all day . Doc said if I did -1.50 and later can do plano when time for other eye and be much more glasses free but I know I would only want maybe 1 or less between eyes at the end of all this. Mentally it feels right and would seem more balanced,

. I don't want any depth perception issues and he says even with the 2 between eyes for now after first eye would not be problem. So in the end have no clue if it would be -1.50 in one eye and shoot for -50 or -.75 in other eye when time comes if can handle that much.

Such an unusual combo so would like to know what the heck would I see with that combo.

With mini-monovision the normal practice is to use the dominant eye for distance and non dominant for near. If I follow your post correctly it would seem you will be targeting your right eye for near?

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My view of the Rayner EMV is that it is really only useful in the near eye, and not the distance eye. The EMV has a very small enhancement of vision to the left of the visual peak of the lens. If the lens is in the distance eye then that enhancement is of no use as it helps at distances beyond infinity. However, if it is in the near eye, then it lets the near eye see further into the distance and closes the gap slightly between the two eyes.

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From what I know of the EMV is that it does not help to the right of the peak visual point and does not have an enhanced depth of focus to the near side. For that reason I would still target it at -1.50 D to get good near vision.

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When it comes time to do the distance eye you can decide whether to go with a monofocal or not, and whether to target it at -0.25 or -0.50 D depending on your priorities.

Being primarily interested in the Eyhance, I've found only two defocus curves for the RayOne EMV. According to Rayner itself, the RayOne is marginally superior to the Eyhance from 0.0 D to +3.00 D; worse than the Eyhance from 0.0 D to c. -1.50 D; and significantly better than the Eyhance thereafter. See "RayOne EMV and TECNIS Eyhance: A Comparative Clinical Defocus Curve".

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In contrast, a study published in January 2022 in the Journal of Refractive Surgery, of which Mayanik A. Nanavatny is the lead author, reports superior vision with the Eyhance, both uniocularly and binocularly, at every point to the myopic side of 0.0 D; nearly identical results from 0.0 D to +1.0 D; and slightly better vision with the Eyhance from +1.0 D to +1.50 D. The article is paywalled, but I was able to get online access through my library. "Visual Acuity, Wavefront Aberrations, and Defocus Curves With an Enhanced Monofocal and a Monofocal Intraocular Lens: A Prospective, Randomized Study".

If you cut and paste the article on Google, you can read it on "Healio."

Hi Ron,

I'm re-reading some of my older messages to gain better understanding. Could you clarify the meaning of the following:

The standard near vision you get with the add in prescription eyeglasses is -2.5 D.

The standard near with mini-monovision is -1.5 D.

Thank you!

Hi Ron,

I think you address my recent question about target intervals here:

When the surgeon uses the computer to calculate your lens power there is one field where they enter the target. That target is in diopters. So if you can settle on a diopter target then there is no possible confusion as to what that means. And, since lenses come in steps of 0.5 D, there will almost never be an exact outcome of 2.5 D if that is your desired outcome. There will almost be two lens powers with one under and one over that desired target. You should discuss which of the options you would prefer. In fact it is best to think in a range 0.25 D apart. For example 1.0 D to 1.25 D.

If my doctor suggested -1.75D as a compromise between -2.0D and -1.5D, what does that mean? In other words, is there actually such a target or more a range?

When you get prescription glasses with progressive or bifocal lenses there will be an Add number. It is normally about 2.5 D. For the lower half of the lens this would be like a person that has perfect distance vision putting on a pair of +2.5 D readers.

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With mini-monovision targeting -2.5 D in the near eye and 0.0 D in the distance eye is too much of a differential. For that reason the reading is compromised somewhat by targeting the near eye to -1.5 D, to reduce the differential between the eyes.

As in my other post, you should ask the surgeon for the IOL Calculation sheet. It will tell you what the options are for your eyes in that range. Your eyes are what they are, and the IOLs come in 0.5 D steps. You will need to choose which standard power to use to get the closest to the outcome you desire. Realistically they have trouble being within 0.25 D for accuracy, so you may be best to set your expectations based on a range.

Hi Ron,

I appreciate your explanation but that is more than I can understand! Would it be possible to answer my question at a very basic level? Think of someone who struggled in math and physics! Again, I appreciate your help and understand if my questions cannot be answered simply.

Could you clarify the meaning of the following:

The standard near vision you get with the add in prescription eyeglasses is -2.5 D.

The standard near with mini-monovision is -1.5 D.

If my doctor suggested -1.75D as a compromise between -2.0D and -1.5D, what does that mean? In other words, is there actually such a target or more a range?

Let me try again. When they measure your eyes and input a target into the computer, like for example, -1.75 D, the computer will calculate what power of IOL is required for your eye to give you that outcome. However, that will only be a theoretical power value, as most likely it will be some fraction of a power that is not available. For example it may say that you need a 15.23 D power lens. You can get a 15.0 D lens or a 15.5 D lens, but not a 15.23 because that power does not exist. So you and the surgeon will have to pick which one you want. The computer will predict what the outcome will be for each available power, but it will not be exactly 1.75 D. One will be a bit over that and the other a bit under, in this example.

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That is why you want a copy of the IOL calculation sheet. It will show you what each power of available lens will give you. You and your surgeon should agree on one.

Thank you so much!!!

RonAKA states that "[a] recent study found the difference [between the Eyhance and Clareon] IOLs was negligble." Context and close reading are important, however, both regarding the limitations of the "recent study" and information available from other studies.

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First, it's not a "study" so much as a video presentation by a paid Alcon consultant, Dr. Morgan Micheletti, on behalf of Alcon at the May 2023 annual meeting of the American Society of Cateract and Refractive Surgery. To my mind, at least, the claims will have more credibility if and when they're published in a peer-reviwed journal.

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Second, the claim made is that visual acuity with the Clareon IOL is "non-inferior" to that with the Eyhance. Dr. Micheletti, the Alcon consultant, makes the claim in the context of reporting that, measuring intermediate visual acuity at 66cm, there was only a clinically non-significant 2.5 letter difference between the Clareon and Eyhance groups (in favor of the Eyhance). According to the example given by Bard (Google’s AI language model), if a patient's vision is 20/20 after cataract surgery with one company's IOL, it is likely to be 20/22 or 20/25 after surgery with another IOL that has a 2.5 letter difference in visual acuity. This small difference, Bard agrees, is unlikely to have a significant impact on the patient's ability to see clearly or to perform everyday activities. But it’s a difference some patients may want to consider.

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Third, Dr. Micheletti also says that the Clareon IOL target-corrected to -0.25 D intermediate visual acuity was non-inferior to the Eyhance group’s distance-corrected intermediate visual acuity with a plano target. All else being equal, making the Clareon group slightly more myopic than the Eyhance group would lead us to expect slightly better intermediate visual acuity for Clareon patients. Given that the Eyhance is designed to provide a modest extension of intermediate vision over pure monofocals, which regularly shows up in published academic studies comparing the Eyhance to the Tecnis 1, it seems a reasonable, if potentially rebuttable, inference that without the -0.25 D difference the gap in intermediate visual acuities between the Clareon and Eyhance groups would have been even more favorable to the Eyhance.

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Fourth, according to Dr. Micheletti, Distance Corrected Intermediate Visual Accuity was 20/25 or better for 10.3% of Clareon patients and 25.2% of Eyhance patients; it was 20/30 or better for 42.6% of Clareon patients and 58.7% of Eyhance patients.

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On the other hand, an academic study awaiting peer review for potential publication in Springer International Ophthalmology reports statistically significantly better intermediate and near vision, without negative side effects, for patients implanted bilaterally with the Eyhance as compared to both the Clareon and Tecnis 1 pure monofocals. There were no statistically significant differences for distance visual acuities. The article is “Visual Outcomes and Patient Satisfaction after Bilateral Implantation of an Enhanced Monofocal Intraocular Lens: A Single Blind Prospective Randomized Study”. Rosa Giglio, of the Department of Medicine, Surgery and Health Sciences at the University of Trieste is the lead author. (Dr. Morgan is identified as the Director of Research at the Berkely Eye Center, but that's not an academic or research institution.)

Rarely does any good come from splitting hairs.

I decided to review my past posts and replies which I'm finding is very helpful. This particular reply touches on a point that I've not yet understood. What is the difference in the above example between -1.75D (as a target) and 15.23 D (or similar) as a power. Do you get from the target to the powers just using the calculations?

The target is just that, something you are aiming for. It is the correction you will require to get your vision to distance plano with eyeglasses. In this example the sphere in the prescription would be -1.75 D. So when you go to the optometrist 6 weeks after surgery this is what you are hoping the refraction will be. It is actually a touch more complicated than that, as there will likely be some astigmatism (cylinder). With astigmatism you can calculate a sherical equivalent. For example if your sphere turns out to be -1.50 D and cylinder -0.50 D, then spherical equivalent is the sphere plus 50% of the cylinger or in this case -1.75 D.

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The power of the lens is what is needed to give you this target plus make any correction due to error in your cornea, plus it has to replace the power of the lens in the eye that is surgically removed along with the cataract. If you had perfect vision except for a cataract before surgery and your target was plano or 0.00 D, you would likely need an IOL power of about +18.0 D. That is the amount needed to just correct for the removed lens.

Thanks Ron!