Symfony set for mid range (-2?)?
Posted , 6 users are following.
I've been myopic since 3rd grade, wore glasses until 15 and then hard contacts exclusively until in my 50s it became annoying to use over the counter reading glasses. Changed to single vision glasses and can look underneath (without tipping them) to see up close really well. Have not needed or gotten used to progressive glasses. Have to read in bed on my side since herniated disc years ago, but easy to see a book up close without glasses. Also don't have the problem of seeing details in the mirror or the shower without glasses or magnification. Since my prescription is around -6, I have "superpower" close-up vision without my glasses. Also have astigmatism.
Now on in my early 60s I need to get the cataract in my left eye fixed. And I've been told that I will then want the other eye done as soon as possible after because otherwise the difference with two different modes of correction will be too big and unpleasant.
The idea of not being able to see up close without glasses is somewhat terrifying. Since I have been delaying, the Symfony was approved and I did all the measurements and then delayed again. It seems like a 16" close-up focal point is as close as I can hope for if all goes well and that's too far for reading without glasses. I'm not even sure if it would be good enough for seeing small details/small labels in daylight without glasses. I'm more willing to wear glasses all the time than to constantly try to adjust with reading glasses on and off during the day.
I thought if I could get the Symfony set at say, -2, I could get a closer focal point of maybe 12" or 13" without glasses and then continue to wear glasses during the day and maybe even get a progressive pair that would also give me the kind of close-up vision I have now.
But I was told that because of the way the Symfony is configured, trying to do a progressive correction over the top is very hard. I was told the most they'll do is -.75 and -.5 "micro monovision" to extend the range a little.
Or I could go with a monofocal at -2 or -3, which would definitely be an improvement of my distance vision and give me a closer reading distance. But that I would need progressives or computer glasses.
Has anybody been through this? What did you do and how do you feel about it? (Maybe I could use armless reading glasses in bed and a magnifying mirror? And get progressives that are clear on top and progress to +4 on the bottom?)
0 likes, 4 replies
sharon_13639 Myopicgirl
Posted
My close up correction for reading, when I wore glasses was 150 power. I also had a small distance
Prescription, and wore progressives. Because of the cateracts and a astigmatism, I decided to have the Symfony Tecnis lens in both eyes. I read my iPhone 6 at 10", I do not have the font set to large print, if I do close up bead work at 6", I then have a cheater pair of dollar store 175's that work nicely.
at201 Myopicgirl
Posted
Based on your background and desires, my suggestion will be as follows:
1. Start with a Symfony lens or Symfony Toric (if you significant astigmatism) set for the best focus at about 32 inches distance. This should give you good vision down to about 14 inches. I know that due to your high myopia, you have had super close-up reading power, but most people don't have it and don't miss it. Typical reading distance is about 16-17 inches for books and about 17-19 inches for the computer scree. Having the Symfony lens in this eye will also give you good vision upto 40 inches range.
2. If you achieve the desired vision with the Symfony lens in the left eye, at that time, my personal top choice will be to get a monofocal lens set for the best focus close to far distance (corresponding to about -0.25D). You will be working with about -1.0 D of monovision, but that is easier to adjust to. The right eye, together with the left eye, will give you good vision at all distances, except in the 4-6 feet range where it will still be good enough. You will also have a better chance of avoiding night vision issues of seeing multiple concentric circles or halos around lights in the distance at night time, which I and many others have had with Symfony lens. (Rather than repeating the details of that issue here, I will encourage you to read my post, “Has Any One Else Had This Very Unusual Vision Issue with Symfony Lens?” on this forum. You should be able to find it by clicking on my name and then looking under “Discussion”.)
Your combination will essentially end up as a slight variation of my lens combination. I have a monofocal lens with best focus at about 17 inches and a Symfony toric lens set for distance. I have also had LASIK enhancement done to both eyes to get rid of any astigmatism. My day vision is good at all distances. But as I mentioned, I do have the night vision issue of seeing multiple circles around lights at distance. Hopefully, you will minimize the chance of that happening by switching the role of the 2 lenses, as I have suggested.
In any case, you don't have to make the decision for the right eye right now. Just start with the Symfony or Symfony toric lens set for about 32 inches in the left eye.
softwaredev Myopicgirl
Posted
There are some surgeons that confuse the Symfony with multifocals, since surgeons are experts in medicine and not always with optics. It has diffractive rings so it looks like a multifocal, but the optics basically merely provider a larger range of vision for 1 focal point, which is an important difference. So
re: "But I was told that because of the way the Symfony is configured, trying to do a progressive correction over the top is very hard. "
I'd find that surprising, so I'm wondering if someone is assuming it'd have the same issues they've seen with patients with multifocal IOLs, or if they have actually seen trouble giving progessives to someone with the Symfony. Basically I'd desribe the Symfony as being like having early presbyopia, when you just start noticing your near vision (when wearing distance correction) leaves something to be desired. i.e . when you hold something too close in you start noting visual quality drop off or say when reading the fine print on an eye drop bottle you might need to adjust where you hold it. However its basically the same sort of continuous drop off in vision as with early presbyopia, so I'd assume progressives would work. I ust haven't had a need for them to bother trying.
Multifocal IOls have 2 focal points (or 3 for those outside the US with a trifocal IOL, not approved here yet), and their visual quality drops off in between. I'm speculating that may make progressive glasses a little confusing to find the "sweet spot". Since the Symfony just has 1 extended range, like someone with early presbyopia has, I'm not sure why it would be a problem.
You can get the Symfony set at any focal point, just like with a monofocal, it merely provides a larger range at whatever distance you set it to. Most doctors assume people want good uncorrected distance vision, but if you'd prefer to have more near at the expense of distance, knowing you may need distance correction, that is your choice. Average results suggest you'd still have about 20/40 distance vision with a Symfony set to focus in at -1D, which is best focus at 1 meter = 39.37 inches=3 feet 3.37 inches.
To see at 12" without glasses, that is a focal point of 30.48 centimeters, which is the focal point of someone (100 / 30.48)=-3.28D myopic. Average results would put you at about 20/20 at 12" for a Symfony set at -1.78, 20/28 for one set at -1.28, 20/40 at 12" for one set at -0.78, and perhaps 20/50 for one set at -0.5D. Suprisingly if you google
"font size" "visual acuity"
you can see what visual acuity is required for what print size, and that is good enough to read small column newsprint. Those are unfortunately only averages of course.
In my case I was a high myope but I wore contacts most waking hours, even with glasses I tended to not take them off for reading since the focal point was too near for me. My least myopic eye was about a -6, but unlike you that was too close in for me to want to read much that way. So in my case I had no trouble going for Symfony implants targeted at distance (though I may laser tweak an eye that wound up farsighted +0.5D down to -0.5D for micro-monovision, it just hasn't been something I need enough to expend time and funds).
In my case I decided before getting surgery that I liked the idea of likely not needing correction for distance or intermediate, figuring that if I needed it for near occassionaly that was a good tradeoff. I did wind up with decent near, typical Symfony results, 20/25 or so at near at more like 16"=40cm, unsure what my 12" vision is, I can read the fine print on eye drop bottles without correction.
softwaredev
Posted
I forgot to address this:
re: "that I will then want the other eye done as soon as possible after because otherwise the difference with two different modes of correction will be too big and unpleasant."
It depends on the person. If you are comfortable going back to wearing a contact lens on the other eye (perhaps trying a multifocal contact lens) then many people cope well with an IOL in one eye and a contact lens on the other.
Otherwise the concern is if you wore glasses that if you needed say 0 correction in one eye after surgery (or even say -2D) that it would be a few diopters difference than the -6D correction needed in the other eye. The problem with that is that glasses change the focal point, but they also change the image size. How much the image size changes depends on the power of the eye glasses, so two different power eyeglass lenses produce 2 different size images on your retina. If the images are almost the same size, the brain can figure out how to merge them into one image. If the image size is too different, your brain may not merge the images, or at minium suffer headaches or other eye strain symptoms to do so. People vary in how much difference the can tolerate, 3 diopters is about the most the average person can deal with, but still may be a strain. They do make special glasses to deal with the issue, but its best to avoid it. The amount an image size changes also depends on how far out the lens is from the eye. A contact lens doesn't change the image size much and so its usually ok to wear a contact lens on the 2nd eye. To look this up, the issue is "anisometropia" (two different lens powers) leading to aneisokonia (perception of two different image sizes, leading to problems).
That said, there are some people who have trouble with a contact lens in one eye and the Symfony another, so you should be prepared to have the other surgery soon just in case you don't adapt, but then can cancel it if you adapt ok. In my case I traveled for surgery (since the Symfony wasn't yet approved in the US) and decided to just get both eyes done a day apart. I felt a sense of imbalance after the first eye was done, with a multifocal contact lens on the other, but I might have quickly adapted, but I didn't give it a chance.