I am myopic with prescription of about -6.5 in each eye. I am getting cataracts now in both eyes and will be setting for monofocals. Visited ophthalmologist yesterday and he suggested that I can have an under correction during lens implant of -2.5 in each eye and remain myopic to see intermediate without glasses. However, I wanted to fix my far off vision with which I have been living all life. I do not mind wearing readers for intermediate vision however, My question is, 1. If I have a surgery of undercorrection with -1.25 in both eyes, will I be able to drive without glasses and yet see the dashboard and gps of the car ? 2. In emergency if I do not have readers, will such situations, will I be able to see my credit card numbers if I keep it far at arms length ? Many thanks to experienced people here.
Everyone’s eyes are different, but I can tell you about my own experience with monofocals. I have my eyes set for mini-monovision–my near eye is at -1.75D, and my distance eye is at -0.5D. While it’s possible (and legal in my state) for me to drive without glasses with my -0.5D eye giving me decent distance vision, I am more comfortable driving with glasses on. I have an ancient pair of glasses that correct me to -1.25 and -.25. I can see the dash clearly with the eye corrected to -1.25, but I would not want to drive with only a -1.25 eye for distance. I can see my credit card number at arm’s length depending on the light–if the card is angled just right with the light causing the numbers to stand out, I can see them fine. If the light’s not good, they’re hard to make out. With my uncorrected -1.75 eye, I start losing a sharp focus at about 27". So it depends on what you’re calling “intermediate”, but a -2.5D target seems closer than you’re looking for–if you end up at -2.5D, your best focus will be just under 16". You’ll still see things farther out, they’ll start getting blurry beyond about 2 or 3 feet.
Thanks so much lucy24197, this sure helps. How about the eye with your distance set to -0.5D, can you see car dashboard/gps with that or can you see what you are cooking with that ?
You can look at the defocus curve for your IOL to get a rough idea, but everyone is different.
If your cataracts are not that bad yet, you can simulate monovision distance with contacts and contacts are relatively cheap. In fact the Optometrist might just give you different ones. So set one eye for Plano and the other one at -1.0 (D) and then various other settings to see how you do.
Another bit of advice that I wish I had taken, is before your cataracts get too bad get a few IOL Master measurements and make sure you get a copy and I would suggest doing it at different offices so they are not the same IOL Master machines. That should include both the astigmatism and Axial Length measurements. You want to make sure they are consistent. Also make sure they do a typographic image and get a copy of that to make sure your corneal is regular and can be corrected with a toric if needed.
Thanks rwbil all good suggestions I will keep those in mind for sure.
Certainly having both eyes done for reading at -2.5 D is an option. @Bookwoman I recall has this type of correction, and perhaps she can comment best on the pros and cons. It certainly does lock you into needing glasses for distance, and driving. I would think even watching TV would be difficult without glasses.
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If you want distance without glasses I would not recommend going with an under correction of -1.25 D in both eyes. To me that just puts you in no man’s land. It would likely give you good vision for computer work, and most reading. You would only need reading glasses for the very smallest print on medicine bottles etc. But, your distance vision would not be good. It may in fact not be good enough to drive without glasses.
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The normal way 90% of people go is to get full distance correction in both eyes. That means setting a target of -0.25 D in both eyes. It is set slightly low to avoid going into the far sighted plus range which can compromise closer vision. -0.25 D can still give you 20/20 distance vision. You will not be able to read up close or probably not even be able to use a computer monitor at normal distance without reading glasses though. You effectively will be like an older person that only needs reading glasses, and possibly computer glasses. I have one eye that was targeted to be -0.25 D and it ended up as 0.00 D. I can easily see the dash in my car and truck with that eye. It may be difficult to see much clearly under 3 feet though. Reading a credit card at arms length would be iffy in my opinion.
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The other option that not all that many go with is to correct the dominant eye for distance, with a target of -0.25 D, and then target the non dominant eye for closer vision at -1.25 to -1.50 D. This is called mini-monovision. In most cases this will give you a range of vision that will not require eyeglasses for 95% of tasks, and you only need reading glasses for very small print. The best way to going down that road is to get the dominant eye corrected for full distance first (-0.25 D), and then temporarily correct the non dominant eye with a contact lens to simulate a monovision under correction. In your case this would be by trying a -5.0 D, and -5.25 D contact instead of a full -6.5 D correction to see which you like best for closer vision and also determine if you are OK with having a differential between the two eyes. Ideally you want to wait 6 weeks or more between eyes, and during that period of time using a contact in the non operated eye is the best solution in any case.
Such a detailed reply RonAKA. I am grateful to you. I was thinking of mini-mono vision as well with one eye -1.25 and other eye -0.25 . That is what I am going discuss with my doctor on the next visit when I am going for the measurements. The question really is what is the closest distance where I will be able to read without reading glasses with this kind of vision. According to lucy24197, it may be 27" (more than 2 feet).
Ron is correct: I had -2 monofocals placed in each eye, although my LE wound up at -2.5. With that micro-monovision I can see well enough that indoors I only wear glasses to watch TV, but I do wear them all the time when outside, for driving, walking, etc. My vision is crystal clear for reading and desktop computer use, and gradually gets blurrier from there, but is still a vast improvement over even my pre-cataract vision, which was -8 in both eyes, not to mention the even worse vision I had with cataracts.
I decided to do this kind of correction after talking to my long-time ophthalmologist (who was also my surgeon). He knows me well, and suggested that my brain would be much happier with what it already knew, so to speak. I spend much of my day either reading or on the computer, I don’t do sports, and I probably drive much less than the average American. Plus, I don’t mind wearing glasses. So correcting for close vision was an easy decision. I decided to choose the same power for each IOL because there are no guarantees that what goes in will be what you wind up with, and didn’t want to risk too great a discrepancy between the lenses.
Good luck with whatever you decide!
According to the defocus curve from a recent clinical study of 45 Tecnis 1 implants, your monocular visual acuity (VA) at 40 cm (=2.5D) in the -1.25D eye should/could be about 0.25 logmar (better that 0.3lm = 20/40), and that in the -0.25D eye sh/could be about 0.5 logmar. You should have decent reading vision for a 6" in smartphone screen at that distance from the near eye. Not sure how the binocular vision may work out (as the far eye would have a blurred image at 0.5lm); not sure if you’d be able to make your brain to show you only the good image. I’ll try to post the defocus image, but I’m unsure it will come through.
I think there is variability between individuals as to how close you can see with a monofocal IOL. My AcrySof IQ Aspheric monofocal in my right eye left me with 20/20+ distance vision, and a residual prescription of 0.00 Sphere, -0.75 D Cylinder. I can read a computer screen with difficulty down to 18-20 inches, and under that not so much. I can easily see the dash in my truck, car, and instruments on my motorcycle with this eye. I am simulating -1.25 D in my non operated eye and I can see dash instruments better with my distance IOL than I can with the -1.25 D eye.
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I find the Jaeger eye chart for reading helpful in determining what my vision is. You can find a copy to print out at the All About Vision site. With my simulated -1.25 eye I can see the smallest J1 text fairly easily. When I correct my distance vision IOL eye with some +1.25 readers I can read the J1 text as well, but I have to hold the page a bit further away. It is not quite as easy. It seems I may be getting a little more than -1.25 with my simulated vision eye. It is still the natural lens so there may be some remaining accommodation even though I am 72. In any case I am going to get some dollar store +1.5 D readers to see how that works with my IOL eye. Working with this eye may be the better way to simulate what I will get when it comes time to do my second eye for closer vision. This is why it is best to do the distance dominant eye first and then use the time between eyes to evaluate monovision with contacts, and also with readers on your new IOL eye.
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IOL powers come in steps of 0.5 D, which does not allow the precision that 0.25 D steps in eyeglasses or contacts give you. Each eye will be an individual decision. You should ask your surgeon after your eye is measured what the closest lens options will give you. For example in the distance eye one power might give you a residual of +0.25, and then next power available -0.25. You really want the -0.25 option. As my surgeon told me, “Nobody ever thanks me for making them far sighted”. It may not be that clear cut though and you should have that discussion. On the near eye, if you go that way, it is probably best to target a range of -1.25 to -1.50 D. There will be a decision required there too on the best available of the 0.5 D power steps. I would expect with your eyes you will be looking at an IOL power of around 12.5 D for the distance eye and about 14.0 D for the closer eye. They use a different range of powers than an eyeglass lens.
The important thing to note in that graph is the error bars on the Tecnis 1 data points. Those that got the best vision in the study were essentially the same as the Eyhance people (average I assume). This shows the variability from person to person of the outcomes of an IOL.
I agree, but that applies to just about every defocus curve out there, as it’s clinically generated and hence a zillion unknowns & random variables come into play. So taking the mean with the caveat of “errors may apply” is the best we can do.
BTW, looking closer at the VA curves (of IQ, Vivity, Tecnis1 & Eyhance) side-by-side, I’m beginning to be convinced that the following blended monovision config may work very well (in your case & others’):
- IQ set for Plano in the Dominant eye
- Eyhance set to -1.0D offset/refraction in the non-dominant eye (NDE)
I call this the IQHance Vision Renewal Solution (on budget and with no halos)!
It should give (in the average case where the above targets are well met)
- better than 20/20 for distance
- better than 20/30 for near
- no significant loss of stereo-acuity for distance/driving vision
- (likely) no significant dysphotopsias
I’ll post some images soon (and/or send you over PM) along with my reasoning based on them. Perhaps you may want to consider it?
And, excellent intermediate vision, I’d add. The config should give better than 20/25 VA (i.e. => 0.1 logmar) over the entire 0-2D range (i.e. ∞ down to 50 cm) (again, in “average eyes” cases).
I have already plotted the IQ and Vivity defocus curves and contrast sensitivity myself with various offsets using data from the Vivity package inserts on a spreadsheet graph. I think combining the Vivity and IQ gives an improved contrast sensitivity outcome, and two IQ lenses actually a little better still. For defocus the Vivitiy at -0.75 D and IQ is pretty good for close vision, and about the same as IQ at -1.25 and the other at plano. The advantage of the Vivity at -0.75 and IQ plano is in the distance vision. The Vivity -0.75 D retains better distance vision than the IQ at -1.25.
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There used to be a good PDF article on monovision which showed the tradeoffs. The full article seems to have been taken down, but the basic summary information and the graphs are still there. They concluded that -1.5 D offset was ideal. I concluded that -1.25 which they did not specifically plot may be even better. But with testing of my IOL eye, I am now tending to agree with them and a -1.5 D offset may be ideal.
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Optimal amount of anisometropia for pseudophakic monovision K. Hayashi, Motoaki Yoshida, +1 author H. Hayashi Published 1 May 2011 Medicine Journal of refractive surgery
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Here is another good article, where they talk about hybrid monovision when a lens like the Vivity is used in the non dominant closer eye.
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Monovision Strategies: Our Experience and Approach on
Pseudophakic Monovision Misae Ito CO* and Kimiya Shimizu
Department of Ophthalmology, Sanno Hospital, Japan
I agree a -1.0 D offset is probably about ideal for the Eyhance, and -0.75 D for the Vivity. And for a monofocal solution -1.25 to -1.50 D.
I can see my car dashboard well enough. I have an ancient vehicle with analog high contrast gauges and no GPS, so I don’t know how a modern electronic dash would compare (it certainly wouldn’t be as fun to drive.) As far as cooking goes–it depends on the type of cooking you do. If you’re just dumping a can into a pot and want to see if it’s sticking while you heat it, it would probably be fine. If you’re the type that uses garlic powder, might be ok. If, like me, you peel fresh garlic and cut any questionable bits off the cloves with a very sharp knife, and then use that very sharp knife to mince the garlic into oblivion, I would be very unhappy with the -0.5 and no glasses. I need to really see well when it comes to preparing food.
There are a lot of issues with predicting what near vision will be. One of the most difficult is that “decent reading vision” can be defined differently from person to person. One person might think that being able to identify words is “decent”, another may feel that they need to read easily and at normal speed for vision to be “decent.” When I use some old glasses to adjust my eye to -1.25D, I can make out a 6.5" smartphone screen at 40 cm (just under 16"), but I wouldn’t find it to be acceptable for general use. I could dial the phone just fine, I wouldn’t want to read important emails or texts with my vision like that–I can make out the words but would be prone to errors. I don’t get sharp vision at -1.25D unless the phone is held out at basically arm’s length–about 25" for me. It would be nice if defocus curves were standardized, with statistically significant sample sizes, but for now they’re probably about the best information the layperson has for predicting visual acuity. And one must take into consideration they are only averages and everyone’s eyes are different. The best you can do is really think about what range of vision is most important to you to be glasses free, decide how much you are willing to risk getting that glasses free range vs getting a larger range of vision, get as educated as you can, hope for the best & plan for the worst.
**no significant loss of stereo-acuity for distance/driving vision
My only advice is try and test this first with contacts if possible. I just had cataract surgery and my vision slowly improved over several days and I can tell you for me the difference in the image the eyes presented the day after surgery did make a difference. With time it might smooth out, but again if at all possible test it out as everyone is different.
Even now for close vision, my 2 eyes are close in vision and bilaterally my close vision is better than either eye is individually.
If you look closely at the defocus curve that you’ve posted, the average best distance vision was less that 20/20. Other defocus curves, other studies, other groups of people come out better. It’s terribly frustrating when you’re trying to make a lens selection. As far as dysphotopsias, I have negative dys. in both eyes with the Tecnis monofocal. It’s not terribly bothersome–much like seeing the rims on a pair of glasses, but it’s there. (The only time it gets a little freaky is when I close my eyes with light shining in my face and I see the dark rims. My brain is used to “glasses frames” when my eyes are open, but when they’re there when my eyes are closed it feels really strange.) I am also having some glare/halo issues, but they may be due to some complications from the surgery and I am hoping they’ll resolve. A monofocal/eyhance combination would probably work very well for individuals with healthy eyes. Just trying to say that everyone has different results; there are no absolute best choices. It’s a very personal decision, and unfortunately most doctors do not take the time to work with patients to determine the best approach to make a patient happy.