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Mini mono vision observations

Posted , 4 users are following.

Dapperdan7
Dapperdan7

so i been pretty half assed about sticking with the mini mono experiment w contacts but im finally doing it daily and so far, my sweet spot is a -1 between distance and near vision. 1.25 was my goal but its a little too big a gap at this point. i do think mini mono is looking more and more to be my eventual choice. that extra depth of focus is nice and my depth perception seems fine.

another point for those on the fence about mini mono is...if your are already considering all these choices, you are already starting to get cataracts and want a solution. im doing the mini mono w cataracts that are not too bad on sunny days outside, less good on grey days outside, even worse in most indoor spaces, and awful at night. if everything goes well with mini mono surgery, my vision will be likely be much better than now since the cataracts will be gone so i look at my present vision w the contacts are a more mediocre simulation of post surgery.

now for the choices of brands and surgeons...and lots more research!

0 likes, 16 replies

16 Replies

  • RonAKA
    RonAKA Dapperdan7

    Posted

    When I was doing my contact simulation with both eyes, and then later with one eye after my first eye surgery, I found that the IOL lens of -1.50 D was about equal to a contact lens simulation of -1.25 D. I believe my natural lenses still had some accommodation despite my being 72 at the time. So, before I discovered that, my plan was for -1.25 in my near eye, but I then revised that to -1.50 D. The contact at -1.25 and the IOL at -1.50 (using +1.50 readers) both gave me about the same J1 vision in very good outdoor light.

    .

    If you do your distance eye first this is easy to simulate. You just put on some readers of +1.0, 1.25, and +1.50. That is a pretty good estimation of the reverse in an IOL will be. Don't forget to adjust for where your first eye ends up. If for example your distance eye ends up at -0.25 D which would be ideal, then you need to adjust the reader value down by 0.25 D.

    • Dapperdan7
      Dapperdan7 RonAKA

      Posted

      so if my distance eye hit plano, i would want the myopic eye to shoot for -1.25 because of the difference between iol vs contact difference if i want to have a -1.0 gap between the two?

    • trilemma
      trilemma Dapperdan7

      Posted

      so if my distance eye hit plano, i would want the myopic eye to shoot for -1.25 because of the difference between iol vs contact difference if i want to have a -1.0 gap between the two?

      A gap of -1.0 from -0.0 would be -1.0.

      Maybe you meant a gap of -1.25.

    • Dapperdan7
      Dapperdan7 trilemma

      Posted

      no. i meant -1.25 since ron said there was a difference of between -.25 between the iol and contact simulation

    • trilemma
      trilemma Dapperdan7

      Posted

      no. i meant -1.25 since ron said there was a difference of between -.25 between the iol and contact simulation

      He was not saying that was a constant that you should use in calculations.

    • RonAKA
      RonAKA Dapperdan7

      Posted

      I like to look at the amount of myopia in the near eye first. That is what gives you near vision. For most -1.5 D is going to give you good reading vision. The gap between the two is what you can tolerate. Most people can tolerate a gap of 1.5 D. You can go for less, but it will compromise your near vision.

  • RebDovid
    RebDovid Dapperdan7

    Edited

    At least with Eyhance, a 1.0 diopter difference is working out quite well for me. Prioritizing near and intermediate vision, I currently -- one day short of five weeks after my second (distance) eye-- am 20/25 at distance, J1 at near, and am able to see well at all distances without glasses. Your mileage may vary.

    .

    Beginning with my near eye, we targeted (on a spherical equivalent basis) -2.0 D and -1.0 D, which meets your criterion for a maximum 1 D difference between your eyes. In the event, 4+ weeks after the second surgery, my eyes, on a spherical equivalent basis, are -1.5 D and -0.5 D.

    .

    Despite my 20/25 distance vision, I'll be getting eyeglasses for potential use when driving in conditions of poor visibility or unfamiliar areas. Since I don't need glasses for reading and do want to preserve my ability to see the dashboard, I'll also employ a mini-monovision approach. My surgeon's optometrist wrote a driving glasses prescription that corrects the astigmatism in my distance eye, which otherwise is at plano, and, in my near eye, corrects the astigmatism and corrects my refraction by 0.25 D.

    .

    Finally, if a 1.0 diopter difference between your eyes is the most you can tolerate, I recommend targeting for a smaller difference with IOLs. (My surgeon and I targeted a 1.0 D difference between eyes based on my successfully trialing a 1.50 D difference with contact lenses both before my first surgery and between the two surgeries.) A variance between refractive targets and actual results is common, without any negligence or lack of skill on the part of the surgeon. In my case, for example, the result in each eye on a spherical equivalent basis was 0.50 D less myopic than targeted.

    • Dapperdan7
      Dapperdan7 RebDovid

      Edited

      hi reb. thx 4 input

      questions:

      1.explain "Spherical equivalent" if you would.

      1. you were shooting for -2.0 and -1.0 for the two eyes but ended up with -1.5 and -0.5 correct? and is this why your distance vision is so good?

      2. you distant eye is plano WITH the eyeglass prescription, correct?

      3. eyehance is and enhanced monofocal lens (Or edof). does that not compromise sharp visual acuity?

      4. and do you target for a smaller difference on the iol so you dont end up having a larger difference than you are comfortable?

      thank you. there is so much to learn. im glad you all are here

      dan

    • RebDovid
      RebDovid Dapperdan7

      Posted

      1. In ophthalmology, a refractive error is an imperfection in the eye's ability to focus light. Sperhical equivalent is a measure expressed in diopters of the eye's overall refractive error. It has two components: the 'pure' refractive error, measured in diopters, minus 1/2 the absolute value of the cylinders (astigmatism). In the case of my distance eye, after surgery and without any correction the spherical equivalent, as measured last Friday, was -0.50 D, calculated as a 0 pure refractive error minus 1/2 my 1 cyl of astigmatism. My near eye measured a pure refractive error of -1.25 D with 0.5 cyl of astigmatism, for a total refractive error of -1.50 D.

        .

      2. Yes. Based on the several defocus curves I found and averaged together, I expected that -1.0 D would make me legal to drive (20/40 or better). Based on my trials of mini-monovision with contact lenses, I also was prepared to wear glasses on a regular basis for driving, watching television, and the like.

        .

      3. Without glasses, the only refractive error in my distance eye is the spherical equivalent based on 1 cylinder of astigmatism. They eyeglasses prescription is designed to correct all the astigmatism.

        .

      4. The Eyhance is not classified as an EDOF because Johnson & Johnson didn't subject it to the necessary FDA testing. One criterion is that an EDOF must increase depth of focus beyond a pure monofocal by at least 0.5 D. I've seen speculation about whether J&J's decision was based on an inability to qualify or a marketing decision to position the Eyhance against monofocal lenses, whose cost to patients in the U.S. is covered by health insurance and Medicare, rather than EDOF an multi-focal lenses whose cost to patients is not covered.

        .

        None of the several articles I've read has suggested any compromise on visual acuity with the Eyhance in comparison to other IOLs. Anecdotally, both my wife, who also has Eyhance IOLs but not mini-monovision, and I see sharply and clearly. The difference is that she needs readers and I don't. Bear in mind that by eschewing mini-monovision she locked in excellent distance vision, which was her priority, and also got very good intermediate vision. My very good distance vision was a possibility, not a lock.

        .

      5. Yes, because even the best surgeons--and I had an excellent one--cannot guarantee that the result will precisely match the target, it's prudent when attempting mini-monovision to leave a margin for (what's called) refractive surprise. Alternatively, one can take one's chances and, if the difference between the two eyes is too great, fix the problem by wearing glasses.
    • RonAKA
      RonAKA Dapperdan7

      Posted

      Spherical equivalent (SE) is quite simple. It is an estimation of the total refractive error considering cylinder (astigmatism) as well as sphere. For example if your refraction is -1.0 D sphere, and -1.0 D cylinder the spherical equivalent is 100% of the sphere and 50% of the cylinder, for a total estimated myopia of -1.5 D. When discussing targets with the surgeon it is important to use SE instead of just sphere, so there is no confusion.

      .

      One complicating factor is that the incision to allow the removal of the natural lens and insertion of the IOL will cause some additional astigmatism. Some surgeons estimate and compensate for that and others do not.

    • Dapperdan7
      Dapperdan7 RonAKA

      Posted

      so when i read my eyeglass prescription and sphere is say -5.25 and the cylinder is -1.0 the SE is -5.25 + -.5= -6.25, correct?

    • RebDovid
      RebDovid Dapperdan7

      Posted

      -5.75. One half of the cylider is 0.5. Subtracting 0.5 from -5.25 yields -5.75.

    • Dapperdan7
      Dapperdan7 RebDovid

      Posted

      oh yeah, 5.75 is correct.

      so you have eyehance in both eyes?

    • RonAKA
      RonAKA Dapperdan7

      Edited

      You have the concept, but your math is not quite correct. It would be:

      -5.25 +(-0.5)= -5.75

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