Worried about monovision iol power specified by surgeon
Posted , 8 users are following.
I was recently told that I need surgery for cataracts. I've been told over the years that I have "natural monovision", and would like to go with monovision/mini-monovision with my IOLs. I have diabetic retinopathy, so it's going to be monofocus lenses (this doctor uses Alcon aspheric lenses, he didn't say what model.) My ideal situation would be able to see a range from reading (I read as close as 10-12") to distance of about 15-20 feet away, then wear glasses for distances/driving. Everything I've read seems to indicate that this isn't really feasible--near and far would be good, maybe or maybe not on intermediate, so I was hoping for monovision, backed off a little from optimum distance in my dominant eye to give me more intermediate vision, then after surgery and some healing decide on the second lens. Today I met the surgeon for the first time. He seemed kind of rushed, and said "our goal is to get rid of glasses."I corrected him, told him my ideal outcome would be to not need glasses for reading or up to about 15 feet, but didn't think that was an option. He said "we can do that!" He seemed none too happy about the monovision request, and said he didn't like to do it for people who haven't tried it (reasonable.) I'd brought in glasses prescriptions spanning several years, and he said "we'll give you what you've had." My glasses over the years have typically run -0.75 sph OD and occasionally up to -1.00 sph dominant RE (with a small astigmatism that comes and goes) with my LE ranging between -1.75 sph and 2.25 sph, again with a small astigmatism that comes and goes. (I'm not counting my last prescription, which was horrible.)
So after the doctor said he'd give me back what I had, he said he'd be doing -1.00 for the RE and -1.75 for the LE.When I tried to ask him questions, he had to go, and said that their surgery coordination would be calling and would answer all my questions.
My concern is that when I use -1,75 & -1 to calculate focal points, they only cover a range of about 57cm-1m (~22-39"). I've also read that depth of field is only about +/- .25-.5 D for monofocals, so best case my distance would only be about 2 meters (~6 feet) if I'm reading the charts correctly, and more likley to be in the 1.3 meter (~4 feet) range.I'm really worried that he's setting me up purely for intermediate and near vision and I'll be stuck in glasses for everything else. Plus it seems like I'll need glasses for near vision, too (I'm a voracious reader and have short arms.) I'm afraid I'll be left with good vision for the computer and not great vision for everything else.
The other thing he said was that for monovision he needed to do laser surgery to hit the targets. If I have to pay the premium for the best vision, so be it, but I was a little surprised by it.
Am I misinterpreting how the lenses work, or am I right to be concerned?
0 likes, 26 replies
rwbil lucy24197
Posted
There is no easy answer. As you are probably aware everyone results will vary. You can start by looking at a defocus curve for the IOl you plan to get. That gives you the average results. Vision is complicated and remember you don’t necessarily need 20/20. So when you say you want to read at 10-12”, which is pretty close range are you expecting 20/20 at that distance? Is so you will need to shift that defocus curve a great deal to the myopic side, which then effects your distance vision.
Let’s start with some basic. The best clearest vision you can obtain IMHO is a monofocal combined with reading glasses.
You stated you want to try monovision and make it more myopic in the dominate eye. Hmmm!
I am going to give you my advice.
1)Find another surgeon. I did not like his responses.
2)If possible with your current vision try monovision with contacts and try different power levels,
3)Give serious consideration to the Light Adjustable Vision. Have you seen the videos on it. If not look on youtube. This lens is Amazing and you can adjust it postop to try different monovision setting. Not sure how many adjustments you can get, so you have to look into that.
lucy24197 rwbil
Posted
The thought with making the dominant eye a little myopic was to gain intermediate vision. Most of my activities are done in the near-intermediate range, with a fair amount up to around 15 feet. I have worn glasses primarily for driving; everything else I've gone without with my lovely built-in monovision. Now I'm wondering if a better approach is to get the near eye done first, see what intermediate vision I have, then get the dominant eye done. Too many variables, too many unknowns. If I have to get reading glasses to be comfortable, that's the way it goes.
My optometrist actually referred me to another cataract surgery center first. I didn't get past making the appointment with them. They were a meat market, and their approach was "we'll pray over you prior to surgery" rather than offering to use the latest technology. Hey, if they want to pray, that's fine, I'll take help from any source, but when that's the primary focus of their literature and web site it makes me a little nervous. Plus their staff was rude, and you never know what doctor you'll see. Truly an assembly line.
It would be nice to try contacts for monovision, but I don't think my vision now is good enough to have them work.
rwbil
Posted
What threw my for a loop was talking about close vision at 10". I mean if you are talking 20/20 at 10" and just glancing at a defocus curve that means you are -4.0 d shifted and your vision would start to get really crappy really fast going further out. I mean even at 20" (2 diapoters out) your vision would start to not be all that good.
I really cannot relate or know the effect of such a decision.
If you are talking about reasonable monovision that is another story.
As I said before study the defocus curve for various IOLs and fully understand it and see what effect shooting for super close vision will have on overall vision.
In the end only you can decide what is best; if you want 10"-20" good vision and be legally blind at distance so be it. What can I say.
Sadly the way medicine is setup in the US it can be a meat market. But keep looking. I meet with several Opthalmologist before I went with the one I choose.
Look for a top Opthalmologist, one that participates in clinical trials, write papers and that you have a rapport with. If in the US, what state are you in?
If you are too high risk for a defractive IOL, maybe look at the Vivity IOL. Setting dominate eye to Plano and the other eye to -1.0 d. And wear reading classes to see Great at 10".
Read up on the Vivity and then schedule to meet with Ophthalmologist that have experience with that IOL. It is odd to me that some folks I meet, I am not talking about you, only go to the first Opthalmologist recommended to them. I personally want to meet several Opthalmologist and get their perspective and basically interviewing them for the job of implanting a lens in my eye.
One other piece of advice, the surgeon does not always hit the mark, so take that into consideration.
lucy24197 rwbil
Posted
Yes, in the US in Washington state. I'd love to use something like Vivity, but my Diabetic Retinopathy is limiting me to monofocals. I'm going to look into LALs, but I'm concerned about long-term stability.
Part of the problem I'm having is determining what visual acuity is acceptable. I've been doing a lot of hanging a Snellen chart on the back of the car, bushes in the yard, etc., and backing off until a particular line (20/30, e.g.) is the last one I can read, then seeing what things look like. Same with a Jaegar chart--I was surprised by what can be read with "bad" vision. (Reading No. 7 only takes 20/70? Really? That makes things better.) Using the defocus curve and making a lot of tables so I can sit down and evaluate ranges of vision.
If the odds were better that the surgeon would hit the target, the IOLs suggested would not be bad. BUT--and a really big but--I found a Review of Opthalmology article that referenced a 2018 study that found in close to 300,000 cases, only about 73% of the results ended up with errors within 0.5 D. ~93% within 1 D. I'm assuming that "within" equates to "plus or minus." That's a lot of potential error. Time to re-assess the plan.
RonAKA lucy24197
Posted
"I found a Review of Opthalmology article that referenced a 2018 study that found in close to 300,000 cases, only about 73% of the results ended up with errors within 0.5 D. ~93% within 1 D. I'm assuming that "within" equates to "plus or minus." That's a lot of potential error."
.
That is one of the reasons why it is always best to do one eye at a time and wait 6 weeks before doing the second eye. You then know what you have. If you do the distance eye first and the surgeon misses on the under correction side, then you can consider doing the second eye for distance and use the first eye for closer up. It is not ideal to do the non dominant eye for distance, but it can be done -- called crossed monovision. That is what I am currently simulating and will be what I end up with when I go ahead with the second IOL for closer up.
rwbil lucy24197
Posted
It sounds like you got it.
It is all about assessing the tradeoffs and figuring out what works with your lifestyle. The IOL I am looking to implant for my 2nd eye, Synergy, is like at the opposite side of the IOL spectrum from what you are looking at.
You have decided to go with monofocal so that gives you a starting point. Then for example if you can live with 20/40 vision at lets say 16" that makes things a lot easier than expecting 20/20 at 10". It sounds like you have figured all that out now and are an informed patient.
My only comment would be LAL would help with nailing the refractive mark, but even though the IOL seems promising, yes higher risk than traditional monofocals that have been around a long time.
On nailing the mark study, that is all doctors. If you are using a top rated doctor you probably have a better shot at getting at least close. And there are devices such as the Optiwave Refractive Analysis system that can help the surgeon hit the mark after the cataract is removed, so you might see if they use that machine.
If the LAL is something you are thinking about there is a youtube video that was interesting. It just shows the amazing things the doctor is doing with that IOL. Search on youtube for:
"The Light Adjustable Lens Live Panel Discussion"
bob38868 lucy24197
Posted
I would bet you will not get what you want with that combination.
I recently got Eyhance lens with the dominate set for +.25 and the other set for -.25. My distance vision is outstanding and I would be 90% glasses free for my lifestyle (most of my reading is at an arms length computer) if I would have been set .5 closer vision. I'm 20/15 both eyes Snellen and would have still been 20/20 at that extra -.5 setting. When I put on my +.5 glasses my close clear focus is 23" and I can read signs just fine on the road. I loose a little distance sharpness as the close eye is then at -.75 and the distance eye is at -.25.
With no glasses on my near clear reading focus is at about 32" but not for fine food content print.
For your case, I put on my +1.5 reading glasses to see how that would line up with your -1.75 close vision eye. My really clear focus is 16" from that eye. You would focus farther away as a straight monofocal does not offer the small amount of EDOF the Eyhance offers. I also put on a pair of +1.25s and found my depth of field starts to defocus at 43" away and farther which would equal your distance eye of -1.
Since the straight monofocal is less flat in the defocus curve I would suspect you will not get what you want. See if you can get the Eyhance lens for as far as I can tell they are essentially monofocal + with no optical artifacts and they give you a little more intermediate when set for plano.
I must say the most difficult thing for me was switching from a lifelong nearsighted world where everything in the house did not require glasses (except when presbyopia set in) to a far sighted world. Having lived it for 3 months now however I would not trade it as I can do everything outside without glasses including driving night and day. The navigation screen on my car is very clear during the day and just a little fuzzy with street names at night. An extra .5 closer would have been perfect...but I already said that.
The .5 monovision I have does not seem to cause any problems and my contrast sensitivity is still good at night...even wearing the +.5 glasses. I might try a +.5 contact in a couple of months to see if I can tolerate more monovision.
I hope this gives everyone some real world numbers to work with. Everyone's eyes are different and there is no guarantee the lens will end up at the expected settings. Pick a really good surgeon.
Night-Hawk bob38868
Posted
Thanks bob38868 for your Tecnis Eyhance experience and mini monofocal testing you have done so far!
The new Tecnis Eyhance Toric II IOL looks perfect for my left eye whenever it needs cataract surgery to go with my right eye that had cataract surgery a few years ago with a Tecnis Toric monofocal for distance.
I just would like to get good intermediate distance vision in my left eye to go with my decent distance vision (from my right eye) for decent computer monitor and smartphone viewing. I currently use +1D added to my prescription glasses for good intermediate distance.
Hopefully with the eyehance IOL it could do similar with only 0.5 to 0.75d less correction compared to the regular monofocal IOL with +1.0d glasses.
lucy24197 bob38868
Posted
I've started using my husband for a guinea pig following your example. His vision is pretty much plano and his accomodation is practically gone, so he's using different power readers/computer glasses and trying different activities--working at the kitchen counter, reading the mail, etc, and we're taking a lot of measurements. I'm thinking that once the first eye is done, I'll be able to experiment with it before finalizing a target for the second eye.
Bookwoman lucy24197
Posted
there is no guarantee the lens will end up at the expected settings
I cannot emphasize this enough. I have -2 monofocal lenses in both eyes (I prioritized near vision over far, since I've been a high myope most of my life and spend 80% of my day either reading or on the computer). My final outcome was -2 in my dominant RE and -2.50 in my LE. This has given me mini (micro?) monovision and I absolutely love it. I only need to wear glasses when I'm watching TV or when I leave the house.
However, the discrepancy could have been even greater, especially if I had targeted some sort of monovision in the first place, and I might not have adjusted well to it. In the end we are still flesh and blood (and vitreous), not machines where you can simply plug in a replacement part and know how it will work. Just something to bear in mind.
lucy24197 Bookwoman
Posted
This is something I'm going to have to look at. I plan to use the defocus curve to figure out what vision ranges are predicted if the target was missed by up to -0.5 in either direction. Plus look at the degree of monovision in extreme cases. Depending on what I find out, I might ask the doctor to adjust which lens he uses. I think the doctor is not entirely comfortable going with monovision for someone who hasn't "officially" experienced it with contacts so he's proposed what seems to be a small amount vs what I've had historically. I took a bunch of old glasses prescriptions with me to the exam so that he could see my eyes are different enough for him to consider it. I haven't worn glasses except to drive (and the occasional concert/movie type of event) and have let my eyes & brain handle what to do to give the best image. If I'm paying attention, and can feel which eye is working, and I'll notice I've turned my head ever so slightly to give the working eye the best view. It's been this way for probably 20 years or more; I'd never even heard of monovision until a few years ago when the doc mentioned that's what's going on. I just knew I had a near eye for reading and a far eye for distance, and it's been great. The frustrating part for making an IOL decision is not knowing what's attributable to the actual vision and what's being done by the brain. I would guess the interpolation is better than extrapolation, but who knows? It's pretty amazing what the brain can do regardless.
gmag22 Bookwoman
Posted
When you wear glasses to help with distance vision, how terrible is your intermediate? Do you find it annoying to have to get further away from an object to see it clearly with your distance glasses? I suppose the other option would be to walk closer to the object and look under your glasses to see the object in focus.
Bookwoman gmag22
Posted
Not sure if you're addressing this to me or lucy, but my glasses are progressives, so I can see well with them at all distances.
Guest lucy24197
Edited
You don't say how old you are or if you wear glasses all the time now. You don't really have "natural monovision" if you wear glasses all the time to correct it. And if you're under 50 it's impossible for the surgeon to "give you what you had" because any accommodation you have left (natural ability to focus) will be lost after surgery. My personal feeling is that the setup you're considering is highly unusual and you won't be happy. I think you may be happier with both IOLs set to near vision and using glasses for TV and outside the house or with normal monovision (dominant set for 20/20 distance) plus glasses when needed. If you want a full range though you probably need a 2.5 D offset which is a very big offset and you absolutely must try that first with contacts. DO NOT do that big an offset surgically without trialling it. And bear in mind even that trial may not be 100% predictive if you still have accommodation.
RonAKA lucy24197
Posted
I think you may be underestimating what a monofocal IOL can do. I have a monofocal Alcon AcrySof IQ lens in my right eye. The target was to leave me with -0.35 D required correction, or slightly myopic, and astigmatism was expected to be less than 0.4. As it turned out my spherical correction is 0.0 D, with -0.75 cylinder for astigmatism. I can see 20/20+ for distance and can see clearly down to about 18". I think to some degree the residual astigmatism is helping me get to get down to that 18" distance. If I had this lens in both eyes I guess I could use a computer with a very large screen and sit 18+" away. But more practically I would need readers. The most important thing the surgeon can do with a monofocal is to not go into the + or far sighted correction range. Much better to be -0.25 than to be +0.25.
.
I would look at this as a process, rather than a single decision. The normal process is to do the distance eye first and target to be -0.25 D, but never into the + range. After the surgery and you find out what you really have, then you make the decision on the second eye. I currently am simulating monovision with the second eye by using a contact that leaves my under corrected by -1.25 D. I like it a lot. Computer work is not problem at all. If I had to work all day reading on my iPhone 8+ it would not be ideal, but for basic stuff it is no problem either. If your vision is good enough in your second eye, I would suggest using contacts to simulated monovision before you do the surgery and choose the under correction amount on the second eye. For me -1.25 D seems best.
.
I don't know of any reason to use laser surgery and both my eyes will be done with conventional methods. That said my astigmatism did increase with the surgery I had, so perhaps that is something that may be avoided with laser surgery. The incision for surgery can impact astigmatism, and the surgeon should chose to make it where the impact is minimized.
.
As for intermediate vision, I find there is no "hole" were I don't see well. For example I can see my car dash instruments with either eye perfectly. If there is a hole, it is at distance. With monovision you are only going to see really clearly with the distance eye, and for the most part the brain has to ignore the image from the near eye. That is why the dominate eye is normally picked for distance.