Laser touch-up

If there aren't premium IOLs in that range, someone could usually get a laser correction afterwards to bring them into that range, and those who are extremely myopic are likely going to need one any way due to the lens power being off if they are trying to avoid the need to wear correction for some distance. For those who need a toric lens, I'd read that perhaps 29% or so wind up with >0.5D of residual astigmatism and are likely also to wish a laser touchup anyway. The Symfony is more tolerant of residual astigmatism than a monofocal in terms of the resulting visual acuity, and more tolerant reportedly than   multifocals.

  

Just as with phones and computers, technology improves all the time. Unfortunately some surgeons had poor experiences with early multifocal IOLs and haven't given newer technology a try, including things like the Symfony that aren't actually multifocals (even though they use diffractive optics which confuses some people). Some surgeons are inherently conservative and would rather never hear a complaint, even if it doesn't give patients an option they might be happier with in the long run. 

For many patients even the minuscule risk of a lens exchange isn't worth it, while for others like me the idea of perhaps rarely needing correction the rest of my life (after having been a high myope needing it all the time, though not as high as you folks) is worth some risk. 

 I have noticeably better dim light vision with the Symfony than I did with multifocal contacts before I had a cataract, and I had no complaints with multifocal contacts (nor do many others) even though I noticed the difference in dim light when I first tried them. Its rarely a  problem so I just never thought about it after noticing it.

There is some loss of contrast sensitivity with multifocals due to light splitting, though less so compared to older multifocals. The Symfony makes up for extended its depth of focus via correcting for chromatic aberration which overalll leads to little loss of contrast sensitivity. Overall some studies show it as comparable to monofocal control IOLs, or at most merely a slight reduction but still better than the average person the same age with a natural lens due to the reduction in image quality with a natural lens even when it doesn't officially yet have a cataract (though the results I saw were for those a bit older, I'm guessing for those in their 40s or 50s like me it may be a very slight reduction, made up for by the greater range of vision).

Monovision can also reduce contrast sensitivity in lower light for some distances where you are only using one eye because you don't have two eyes gathering light. 

I figured in the unlikely case I did have some other eye health issue develop in the future, that I could get a lens exchange to a monofocal, but that the odds are high I'd never need it. However everyone's risk tolerance is different. 

I have also read of conservative surgeons who avoid multifocals due to possible complaints, but that's not the case with my surgeon. I know that he uses Symfony IOLs for other patients, but he did not recommend it in my case.

It is still early for me, so I don't have a post-operative refraction yet.  However, the monofocals are quite acceptable in terms of spectacle reduction, which was a surprise because I was much more interested in the Symfony before talking to my surgeon. The astigmatism seems to have been effectively corrected by the toric lens in my left eye and by LRI in my right. I seem to be myopic in both eyes but more myopic in my right.  That results in a quite usable range, as I can see distance clearly with my left (and acceptably with my right), whereas intermediate vision is quite clear with my right (and acceptable with my left).

I can drive and use my desktop computer comfortably without glasses.  I can also use my phone at arms length, though it helps to bump up the font size a bit. Reading glasses are necessary for small print and long reading sessions, but that's fine.

Night vision degrades in my right eye but seems fine in my left, which has a different IOL design (aspheric) than my right. So night driving is comfortable using both eyes.  While driving, I can see both distance and intermediate (GPS) just fine.

In terms of numbers, I was at 20/40 (one week out) right eye and 20/25 (one day out) left eye.

I guess I'm saying that being left slightly myopic (with astigmatism corrected) post-op, with one eye more for distance and the other more for intermediate seems to have worked out so far in terms of usable range.  Hopefully it stays that way.

So, for r28705, I would also think that targeting slightly myopic for the other eye might be more useful than targeting 0 D. That also might reduce the chance of winding up hyperopic in the remaining eye as well.

I could ask the surgeon to aim at -0.5 in the other (right) eye, but am not sure if there is a risk it might then come out at -1, as there is a margin of tolerance, especially if you are highly myopic?   Not an easy decision!  decision !  

Actually, as I indicated earlier, you may be even happier with -1 in the right eye than having -0.5 in that eye.

Thank you. That degree of difference should help with my concern of my depth of vision being too small and therefore needing multiple pairs of glasses !   I was slightly surprised the surgeon felt I wouldn't be happy with -1.      He suggested having the right lens set for reading, but I think that medium distance wouldn't then be in focus - and I need to see well at arms length for playing the organ and at 1 metre when teaching so I can follow the students' music

. 

I don't recall the exact number, but my right eye (20/40 UDVA) was worse than -1.0 D (-1.25? -1.5?) with zero cylinder at one week after surgery using manifest refraction.  BCVA was 20/20. In good light, my right eye can read text clearly without glasses down to 20 inches.  That's good for using a desktop computer monitor — I'm not sure how it compares to reading music.

Caveat — this is just one person's experience. Depth of field reportedly varies by individual for any number of reasons including pupil size.

I am not sure why this message (and the previous one) are showing up at more than one location in this post. Any way, our subsequent discussion at the other location in this post has hopefully answered your questions.

Its fortunate it sounds like you had fairly decent results with what sounds like monovision, with an added near boost by likely having both eyes a bit myopic.

We'd need to know what your best corrected vision is to know what the 20/40 for the right eye means (e.g those with other eye health issues could be corrected to 0D and still be only 20/40, while someone with best corrected 20/12 vision or something could be further in). Odds are it  could be its focused at -1D or slightly more inwards which is 1 meter or a bit less. Even the 20/25 eye is likely a bit myopic (again, depending on your best corrected vision).

 Its hard to tell, but I'm suspecting a larger than average range of useful focus. Unfortunately people's results do vary depending on the depth of focus of the rest of their eye, so they should be careful about hoping for the same results as someone else and try to get a sense of what is average/typical and expect that, while hoping for the best and preparing for the worst. My results with the Symfony seem to be fairly typical based on the studies so I don't tend to emphasize that results will vary. 

 

Although its possible they are setting expectations low, I tend to see doctors suggesting with a monofocal set for distance to expect things to get blurry from 6 feet inward, while some lucky tiny minority get some farther out reading vision with that, and others report blur starting more like 10-12 feet outwards.  Obviously of course monovision is what extends that range quite a bit, especially if you don't mind distance vision being not quite 20/20.

Here's an update, since there was a question about my best corrected vision.  I received my post-operative refraction, and my left eye is plano with zero cylinder and my right eye is -0.75 sphere with 0.25 cylinder. BCVA is 20/20 for both.  So there might be a bit of monovision, but it's minor and I seem to have reasonable depth perception.

So far, I have been fine with over-the-counter progressive (multi-focus) reading glasses when using a computer and reading documents at my desk. I have ordered prescription single vision computer glasses, which the optometrist thought should work for both computer and reading (but not detail work).

The optometrist did mention that some people seem to have a degree of temporary accomodation with monofocal IOLs during the first month or two.  I'm crossing my fingers that my current vision stays stable beyond that time.

The only issue regarding the cataract surgery after LASIK is that the measured cornea readings may be slightly off at the time of the cataract surgery, which may make the calculated value of the IOL power to be slightly off. Thus, the standard recommendation is to be sure that there is a good record of the cornea readings before and after LASIK so that the related information is available at the time of the surgery.

Other than the fact that any surgery, including LASIK, has a risk (although very small for LASIK), there is no additional risk because of having LASIK done after the cataract surgery. Just for reference, my eye surgeon includes free LASIK enhancement after a multifocal, toric, or any other premium lens. Of course, that made it a very easy decision for me to have a LASIK enhancement after getting a Symfony toric lens. I needed that primarily to correct the remaining astigmatism and I am glad that I had that done.

In addition to concerns over the lens power being more difficult to get right after lasik, the concerns are usually over earlier generations of laser correction where the cornea may have been left more irregular and less smooth than modern methods (picture by analogy a high resolution display screen where you can't see the pixels, vs. a lower resoltion one where you can see pixels and images aren't as smooth).

Although some surgeons who aren't up to date  or don't have the equipment may rule out a multifocal for someone with past laser correction, better surgeons can do eye scans to look for the size of irregularities, the higher order aberrations, to determine whether a diffractive IOL (a multifocal, or the Symfony extended depth of focus lens) would be a problem (though it shouldn't often be with the Symfony, it takes fairly large irregularities to cause problems for it). 

The corrections made after cataract surgery now are usually small (which means even those with corneas too thin for large corrections are candidates) and are done using modern technology which leaves the cornea regular enough to interact ok with a diffractive lens. 

I'd read that some surgeons prefer PRK rather than Lasik after cataract surgery, but not all, I hadn't explored the reasons other than that its a smaller correction than people usually get done with a laser.

 

I think it probably best to have my right eye cataract done, and to wait to see the resulting prescription after a month or two.  

Then to ask the surgeon to reduce the strength of the monofocal iol in my left eye, as I am not very comfortable with it being at +0.50, cyl -0.75.   Distance is clear, but not mid distance - eg the tv isn't in focus at about 9 foot away.  

If the margin of error is plus or minus 0.5, then I suppose it could be reduced from +0.5 down to 0, and then if it overshoots, it will end up as -0.5, which would be fine.  

(The surgeon said a reduction from 0 down to -0.5 is not a good idea, lest it goes down to -1 and I would then be back for another touch-up).

I could make another appointment specifically to ask him this, and also whether he could look into the suitability of the symfony lens - although the reduced contrast might make reading in low light conditions awkward - or if I developed macular degeneration when older - if this is more likely for high myopes ?  

 

I responded to these points in other replies above. As I noted, although I'd do a contact lens trial to be sure, in my case at the moment I'm guessing I'd likely shoot   for going from +0.5D down to -0.5D, since I don't think -1D would be too much for a worst case myopic result (since my other eye has at least 20/15 distance vision), although I'd prefer less. I just know that being hyperopic seems a waste, I just get enough near from my other eye that Its not been a high priority to fix. I suspect if I had a monofocal rather than the Symfony that I would have made it a high priority. 

Have just seen your post - I agree requesting 0.5 is a safe option, since the lowest probable outcome of -1 would still not be too low.  

I'll request a test contact lens for the left eye at -0.5, and also one at -1 meanwhile, and try them out for night driving (as a passenger)! 

If I ask the surgeon to target -0.5 in the right eye when the cataract operation is done, but it overshoots and comes out at -1 (allowing for the 0.5 margin), do you know what the focusing distance would be?  I will need to think carefully about whether to go for this option, or just to let the surgeon achieve the standard full distance prescription, as he did in the left eye.  It might be safer to try monovision using glasses or lenses, rather than with iols, so it would be reversible if I didn't get used to it.

An eye focused at -1D is focused at 1 meter = 39.37 inches. The formula is distance_in_cm  = -(100/ focal_point_diopters). The reverse is focal_point_diopters = -(100 / distance_in_cm).  That is just the point of best focus, lenses tend to provide some decent vision inward and outward of that. I think I'd posted on this page (not taking time to hunt now) that I seem to recall that although the range depends on the person and the IOL, for a -1D lens that might give 20/32-20/40 vision or so, perhaps even meeting the driving standard without correction. 

If you try monovision with IOLs, or in general set an IOL for a certain distance, then if you don't like it, you can wear correction over top of it to correct  it until you get a laser treament to permanently correct it.  If you like the distance its set for, then you have saved a step and don't need laser correction to set it to where you want.

 

Thank you.  Would a monovision setup with the left eye at 0 and the right at -1 give continuous focus from 39.37 inches to infinity, or would there be a distance in between that is out of focus?

As I need various reading distances from the close smartphone to reading music at arm's length, I will need varifocals to cover that, then I could take my glasses off for distances in the first para.  

One of the main decisions is what distance to use glasses - either a) for the various reading distances in the first para, or at the other extreme, for driving (or at least night driving)?  Perhaps countryside walking or swimming are the activities for which glasses or goggles would be the most inconvenient ! 

 

With the monovision setup with the left eye at 0 and the right at -1, you should be able to see 20/25 or better from about 26 inches to infinity, provided you have only a small amount of astigmatism and no other vision issues.

The near eye has some vision outwards from -1D and the distance eye fairly decent  for a ways inwards  so between the two there likely won't be much drop off, and you might potentially have good enough vision for driving even if it might be best to wear correction. It seems a useful range for things like walking and swimming (though you might potentially need a decent size watch font if its lap swimming, but they are there).  Its up to you which distances you prefer to risk the need for glasses. 

Many people consider it most convenient to risk needing them for near since they can have readers at home/office. Smartphones can be set to use larger fonts  if needed. For use out and about, there are foldable readers that fit in the pocket, or another page notes there are foldable readers without arms that just perch on your nose and  attach to keychain or in a pocket thats on a smartphone case, or in a wallet size. There are apparently also credit card size magnifiers for small text, or credit card size readers that you need to hold up (they dont' stay perched on the nose). There are smartphone magnifier apps to read a bit, using the camera to magnify the text and the flash to light it.