Monofocal set for near (how is your arms-length vision when wearing glasses for driving?)
Posted , 7 users are following.
If you have a monofocal IOL set for near and wear glasses during the day to help see distant objects (like when driving a car or watching movies) how good is your intermediate vision while wearing these glasses? I'm very interested to know if I get a monofocal set for near and wear glasses during the day if I could realistically work at a computer for hours without being uncomfortable? My computer screen sits about 30-40" away from me (which, in optical terms, equates to a lens distance of about -1.25 to -1.0 D). I imagine if I had a near IOL it would be set somewhere around -2.0 D.
To provide more context, I'm trying to decide what IOL to pick for my dominant right eye (cataract is becoming very symptomatic and will need surgery soon). My non-dominant left eye already has a multifocal IOL which gives me 2 focus points at -4.25D and -1.75D. The multifocal has horrible side effects though so I've decided I must pick a monofocal for my dominant eye. I work at a computer all day long and love using my iPhone & near vision quite frequently. I also thought about maybe going with a distance vision IOL but I'm worried the difference in diopters would be too large between my eyes. I've basically narrowed it down to either a near IOL (set to around -2.0 D) or an intermediate IOL (set to around -1.0 D) in my dominant eye are the best choices.
Any thoughts or experience that could help with this decision is greatly appreciated! I'm also 30 years old with a high possibility of becoming more myopic with time (which makes me think the intermediate choice might be better considering it could shift over time)
0 likes, 14 replies
RonAKA gmag21
Posted
Can you do computer work and read with your multifocal eye only? If you can, then my thoughts would be to go for distance monofocal in the other eye. I have seen reports of monovision up to 2.5 difference being used, although that sounds high too me.
Is your right eye good enough now to judge how it will work for you at different corrections? If so you could try different powers of contacts now to see what you can tolerate for difference between the eyes. That is quite common before going to monovision.
gmag21 RonAKA
Posted
Thanks for your response Ron! I can see extremely near (at 8") and a computer screen placed closer than ideal (at 20" away) without glasses in my multifocal eye. I feel like my dominant eye is still contributing quite a bit for very close reading (which is why i thought about possibly selecting a near IOL to supplement the multifocal eye). I think my general goal for my vision is to be as comfortable & clear as possible (even if i have to wear glasses after surgery).
I tried putting a distance correcting contact in my dominant eye (with no rx on the multifocal eye) but it feels kind of weird... mainly because the halos in my multifocal eye are pretty bad at distance (unless I'm wearing glasses over that eye, which seems to significantly reduce halos). I actually like the idea of wearing glasses after surgery since it can somewhat aid the halos in my multifocal eye. I figured going with intermediate in my dominant eye could allow me to push my computer screen out to around 30" (a more normal viewing distance) and still require me to wear glasses for tv/driving (which helps the halos in other eye). I'm also a very analytical person and easily notice differences & imperfections between eyes (so if i had distance IOL in right eye i still might want to wear glasses for distance so my other eye could be equally contributing). This is why i think the decision is between near or intermediate for my case. Definitely could not do another premium lens in this eye due to the necessity of night driving. I should also mention the current Rx on my dominant eye is -2.0 SPH which means my unaided near vision is excellent. If i didn't have a cataract in this eye I'd say my overall range of vision is perfect (although i realize my right eye also has the ability to accomodate which obviously wont happen with the monofocal IOL). I like the idea of near IOL because without glasses my two eyes would be nearly the same. If i do intermediate it would be like mini or micro-mini monovision which i think gives me more range than the former. oh decisions decisions.....
Guest gmag21
Posted
Hi
I don´t have monofocals, so I don´t have experience with those.
How much close vision you get from a monofocal set for distance will vary from person to person.
There is a big difference if you, with your natural vision, had 20/25 or maybe 20/16.
If you drop two lines because of "wrong" distance, it makes a big difference if you drop two lines from 20/25 to 20/40 or two lines from 20/16 to 20/25.
But if we go down the theoretical road, and I am sorry, but I think your optical powers are a little bit off - if you want clear vision at 32" your need +1.5 added to plano, and if you want clear vision at 16" you need +3.0 added to plano.
A monofocal that hits theoretical plano, will give you usable vision to about +1.0.
And if you have a monofocal set for far with 20/20 vision, that hits plano, it will give you 20/32 at 37".
20/32 is considered to be usable vision, where most people does not need glasses.
Maybe your vision is better than 20/20 to start with, maybe your monofocal does not hit plano, maybe your brain have better adaptation. But many people will not get comfortable pc screen vision with a monofocal set for far.
Edof is made for covering the range you are seeking, although I know you are not keen on the side effects from the edof.
gmag21 Guest
Posted
What about a monofocal set for near, wearing glasses to aid with distance, but trying to focus on an intermediate object like a computer screen (with the driving glasses on)?
gmag21
Posted
Also, to be clear, when I was talking about -1.0 or -2.0 D I was referring to the refractive error created by the lens. So if a monofocal was set for -2.0 D of error it means you need a -2.0 D prescription lens to correct the eye for good distance vision. And -2.0 D means the clear focus point (unaided by glasses) is 1/2 meter away which is the same as 19.7 inches away. Is this not correct?
Guest gmag21
Posted
This - or + can be a bit confusing. And so can meters and inches 😃
But what I meant was, that you theoretically need higher diopter from plano in relation to the distance than you mention, if you are going for best vision.
With a monofocal lens set for 2.0 to the near side, in theory it will have perfect focus point at 65cm.
So 2.0 is not considered near vision, it is considered as intermediate.
Trifocals have powers of 3,2-3,5 for near.
Even a monofocal have a little bit of range both sides of plano, so most people experience usable vision 1 diopter on both "sides" of plano, even that the vision get worse and worse, the more out of focus the image get.
So with a monofocal 2.0 from plano, most people would experience usable vision from 1.0 to 3.0. This is why most people would get good reading vision with a monofocal at 2.0, because it covers the reading reading range at 3.0 as well, even that the best focus will be at 65 cm at 2.0
A monofocal set to 1.0 (minimonovision) will in most cases give useable vision from 0.0 to 2.0. Off course the peak focus will be at 1.0 (95cm) but still usable vision at far 0.0 (often 20/32) and also usable vision at intermediate 2.0 65cm (often 20/32)
But in real life the human factors comes into play, so what we end up with is always a bit of a gamble, some get more, some get less 😃
gmag21 Guest
Posted
Very Interesting.... So the perfect focus point for a -2.0 IOL target is 65 cm, not 50 cm? My doctor told me you take the 1/diopter to calculate the focus point in meters. 1/2 = 0.5 m = 50 cm
Guest gmag21
Posted
Sorry, I hate it when people in forums think they no more than the experts, like I do now - but in this case, I think your doctor have told something a little bit from the truth.
As I mention, trifocals have a lot more than 2.0 for near vision, my Zeiss Lisa trifocal have 3.33 for near, 1.66 for intermediate.
The edof lenses, Lara and Symfony, makes about 2.0 of usable vision, and they normally gives you clear vision within an arms length, they do not give you real near vision. Unless you are one of the lucky few, that get more from a lens than most others.
To make it all more confusing, iol diopters and glasses diopters are not the same, there is a 1/3 difference.
And to make it even worse, the iols diopters are calculated at a mean iol power at about 15. If the iol for your specific eye is lower or higher, the iol diopter will/must be tweaked accordingly.
So it is much more complicated than us "Google experts" can figure out, and the eye doctors are saving us from all this confusing information 😃
.
I can not put in links here, but please make a google search for this text, and go to the site, here you will see a simple explanation, with some images to show how it all works:
blog/symfony-or-trifocal-intraocular-lens
ara21947 gmag21
Posted
My eyes are both monofocal set to near 1.5. My computer vision is probably my best vision, as is dash on car. I can see tv with or without glasses but it is clearer with glasses. I use glasses for driving. I am astigmatic and have toric correction in iol and a bit in glasses too. I do read without glasses tho not as easily pre surgery when I was very near sighted. If my vision was set to any closer, I would have lost more of my intermediate and distant vision.
gmag21 ara21947
Posted
Thanks for your feedback! Are you happy with the -1.5 in both eyes? Do you wish one of your eyes was set slightly closer for improved reading ability or perhaps you prefer/appreciate the balance you have with both eyes being equal?
Mutti3 gmag21
Posted
just as a side note, i have my left eye set at -1.50. i noticed that my intermediate distance was good, but the distance was a tiny bit blurred. when i had my right eye, i choose more distance. Now i have a mini mono. No glasses for distance, intermediate is good, wear" cheap reader" for close. But if i am in a well lightened area, i see great in all distances.
ara21947 gmag21
Posted
I asked for the 2nd eye to be set maybe 1.75, just a little closer, and he said that small a difference wouldnt do much. The concern is the closer you see, the more you lose in distance including intermediate. (in my heart I do wish I was a teeny bit closer but I read books ok. I was just used to seeing the smallest print in any light so maybe I need a different mindset.) The balance between my eyes is important to me for near tho one is 20/40 for distance and the other worse. They even out when my glasses are on.
gmag21 ara21947
Posted
Do you wear bifocal glasses during the day or just regular single-vision glasses for distance correction?
ara21947 gmag21
Posted
Glasses just single vision set for distance. Just got them and Im marveling at the blue sky but so is everyone else so weather might just be splendid these days in my area. Ive never worn bifocals.
'I dont know what the future brings since our eyes with IOLs single focus no longer accommodate.