Trying to understand diopter difference between 2 eyes...
Posted , 5 users are following.
I am trying to understand something.
As things stand, 7 days post OP my wife's LEFT eye is currently @ -1.5 (Premium Monofocal IOL)
Her NON operated right eye which used to be +0.5, just three months ago is currently showing +1.75!!! (Btw 5 days ago right eye was showing +1.5!)
Question 1- Is that big change from 0.5 to 1.75 in the right eye due to the cataract getting dense? It was a fast spreading cataract.
Question 2- Wife sees blurry far. I assume that is combination of right eye having dense cataract + left natural lens being removed and replaced by IOL set for near.
My question, is the big difference between left eye (-1.5) and right eye (+1.75) = 3.25 diopter truly REAL?
What I mean, is it"similar" to when people have full monofocal vision? OR does it not count as she still has accommodation in the right eye?
She feels slight nausea when looking far in crowded areas like railway station and airport. Could also be purely blur related rather than diopter difference related.
Could someone throw some light?
0 likes, 22 replies
W-H
Posted
TYPO
I meant-
What I mean, is it"similar" to when people have full MONO VISION?
Night-Hawk W-H
Posted
My right eye with a cataract got a lot more nearsighted due to the cataract effects so initially I could correct it by getting new eyeglasses with a bigger Rx, so yes the Rx can change quite a bit as you describe until it gets bad enough that it can't be corrected good enough with glasses and when that happened I went for the operation and got a Tecnis toric monofocal for that eye. My other eye doesn't need surgery (probably not for years) since it still corrects to better than 20/20 with glasses and has the same Rx its had for 30years or so.
If the eye still has a lot of accomodation (less than age 45 or so) then it would you would have to subtract some diopter, so the difference between the eyes wouldn't be as big as expected, so it wouldn't be the same as true monovision with IOLs in both eyes and no accomodation. Most folks can handle up to about 1.5D diffference but beyond that can cause issues.
W-H Night-Hawk
Posted
Thanks for the confirmation. Night- H
She is 43. The other eye will be targeted for -0. 25 end of the month so difference between the eyes will be around 1 to 1.25 diopter.
Her right eye cataract has become very dense so I don't think it can be corrected.
If she wears throw away glasses it just makes the blurry vision larger.
All 4 surgeons plus our ophthalmologist had said that it is fast spreading cataract and that they would get both eyes done within 3 months.
We got left eye done at month 3 and right will be at month 4.
Sue.An2 W-H
Posted
Hi Worried-H
Yes most definitely the cataract getting more dense and spreading can cause prescription changes and eventually she won't see well even with glasses. That can happen quickly. Mine changed within 6 months. Aug of 2016 my eyes could be corrected with glasses to 20/20 and in Jan 2017 I could not even read big E on eye chart with those glasses. At that visit I was diagnosed with cataracts and referred to a surgeon.
Yes due to wife's age she has a lot of accommodation so the diopter difference is not affecting her ability to see. Ideally you would not want that target / difference between eyes after 2nd surgery any more than 1.25 unless she was comfortable with that set up with contact lenses before cataracts. The greater the diopter difference harder it is for brain to adjust and blend the vision. Can result in double vision and depth perception.
Sounds like RE is doing well and focus is good now. She must be happier now to see!
W-H Sue.An2
Posted
I assume you mean the left eye, as that was the one operated, don't confuse me lady 😃
She is seeing SUPER SHARP and excited like a child! I am so happy for her.
That is the funny part, my wife's cataract came so fast that it went from all good to very bad in 3 months! There was no time period where glasses helped.
Using cheap readers helped for 2 weeks maybe but only for magnifying the blurred text. Sharpness was always GONE!
No one knows when the cataract actually started. My guess would be not more than 1 year ago...maybe 2 at max. I guess no one can truly answer that!
Sue.An2 W-H
Posted
Not trying to confuse - was referring to operated eye. And yes with everything so sharp, colorful and in focus one feels like a child taking in our beautiful world for first time.
I think you picked the right surgeon and it's obvious aftercare has been top notch. Whether Dr Rockstar would have been as attentive doesn't matter.
At this point don't stress and think about the diopters - IOL calculations are different from glasses - Danish I am amazed at all you know!
Worried I am positive wife's surgeon will know from follow up visit just where to target your wife's other eye so that vision is blended and she'll have best outcome possible.
Guest W-H
Posted
It will all be a totally different matter, when second eye is fixed.
When I had one eye fixed and one eye with cataracts, my brain was really having a hard time making the eyes work well together, it took a couple of weeks before it got semi-good, the wait between the surgeries was killing me.
But when the second eye was fixed, the blended vision worked great day after second surgery.
About all this diopter stuff - there is a big difference between the natural lens and the iol, so you really can not in any way compare now, and what you will have when both eyes are done.
And to make it even more confusing, diopter at iol plane and diopter at spectacle plane is not the same, and this is one of the reasons to many misunderstandings.
The ratio between iol plane and spectacle plane is different from person to person, it depends on eye measurements, but as I remember 1.0 at iol plane equals 0.7 at spectacle plane with a mean value of 15 diopters at far vision.
When eyes are measured to find out if we need glasses, it is usually spectacle plane diopters that are measured.
And when eyes are measured for calculating the right iol, off course it is iol diopters that are measured.
But sometimes the measurements are converted one way or the other, and when we don´t know if the measurements we have is one thing or the other, we could easily be trying to compare apples and pears.
soks W-H
Posted
yes. i went from -2 to -2.5 and now at -3.5. it is really more cataract in the line of sight.
can the right eye accommodate for all distances after +1.75 correction?
soks W-H
Posted
in the iol eye how is the distance vision? does it become blurry after certain distance? also how are the street lights at night?
W-H soks
Posted
Right eye already accommodates for all distances as it is non operated natural eye. Left eye is the operated eye and currently sitting at -1.50.
How do you correct +1.75 natural eye? I thought you can correct -1.75 by buying readers for +1.5 or +2.0 etc but I don't know what you do for a +1.75 eye? Are there -1.5, -1.75 cheap glasses?
Anyway her right eye is very badly covered with cataract so no glasses will help her. 20 more days and it will be gone!
Sorry if I did not understand your question 😃
*For sure it becomes blurry in the IOL eye as it is set for near and not distance 😃 She sees everything but can't pick the minute details. So for example she can see restaurant across the road, 10-15m away. She can see that it has a large red sign with restaurant name on it, but she can't read the name
Some quick tests we did when we read your post while we were out in the city on a rainy, cloudy and gloomy evening (6pm). Not bright as winter is kind of here in Europe.
Her Zeiss Monofocal -1.5 IOL left eye gives her sharp..ish vision upto 2m.
She can read parked car number plate at 2-3m.
She was able to read text on side of a car from 4m (with some blur), the text was 8cm in height.
She could tell correct time on top of a church tower clock 20-30 meter away (with blur). Clock is maybe around 1m-2m in diameter.
She checked street lights and car headlights for you using only one eye at a time...
I hope that helps. If anymore questions then let me know.
Sue.An2 W-H
Posted
With cataracts night vision for me was bot good. Halos around lights, glare, and contrast sensitivity really deteriorated at night. Got to a point I was concerned I'd not see a person crossing the street if they were dressed all in dark clothing.
Perhaps going from that state to where I am with Symfony night vision I can say night vision has vastly improved. Not nearly as bothersome as cataracts were. I bet your wife who had very good vision prior to cataracts (not needing glasses) will find it hard to recall what good vision was and all will be so much better with IOLs than it was with cataracts. I think primarily that is why lasik or clear lens exchanges are done on both eyes same day - so there is no comparing the operated eye with a good eye.
soks W-H
Posted
thanks for the tests. i would like to know how much she loses her near when she puts on -1.5 glasses on the operated eye. of course these glasses will make her distance crystal.
on the unoperated i thought she needed +1.75 glasses. thats means she would need +1.75 readers. i thought she went from +0.5 to +1.75 but it would appear that she went to needing -1.75?
looks like she has got a good result with the mini-combo. you should be relieved. the next eye will make distance crystal and add some more to the near due to binocular summation.
W-H soks
Posted
She has $3 glasses that say +1.5 on it not - 1.5
Anyway she put them on the operated eye for you and tested on her phone for near vision.
If without glasses she sees mobile phone super sharp @ 50cm then with +1.5 glasses on she sees mobile phone at the same 50cm distance very blurry, unable to read the text.
If she pulls the phone maybe 10cm closer then she sees it super sharp again.
No they won't and they don't 😃 We already tried that yesterday.
We have +1, +1.5 and +2 cheap readers in the house. None of them make her -1.5 IOL eye sharp for far.
I think it has to do with what Viking was saying earlier that - 1.5 on IOL plane is not same as the glasses plane.
Which is why based on her near sharp point distance I wrongly using online glasses diopter converter had assumed that her operated eye was off the target by a lot... - 2.5. When in reality tests showed it was at -1.5.
On Monday I will try more glasses on her in the shop. My guess is +3 or above glasses will make her distance vision sharp for her.
soks W-H
Posted
-1.5 glasses will make her distance sharp. the '-' glasses are not available over the counter in the US. the iol and spectacle
difference is about -0.5. but it is not big enough. the + glasses will make her more near sighted.
Guest W-H
Posted
Well, there is another difference between iol plane and spectacle plane other than diopter ratio.
Iol plane and spectacle plane have opposite +/- and it makes it all very confusing 😃
The reading glasses called +1.5 is moving the focal closer, if it was an iol with a +1.5 it would move the focal point further away.
Very confusing, even for a nerd like me, it took me a while to figure it out 😃
Anyway, you need opposite glasses than the ones you have now if you want to move the focal point to far vision, you need glasses made for nearsighted people for this task.
The glasses you have now is made for treating presbyopia.
So you need glasses named -1.5 (maybe -1.0 will do it) if you want to move the focal point to far distance vision.
And there are just as cheap "-" glasses on the marked, you just don´t find them in supermarkets that often, but i have seen these very cheap on the Internet.
W-H Guest
Posted
Good to know! Makes kind of sense. Normal shops around here don't have (- / minus) glasses.
Guest W-H
Posted
I am sure you can find minus glasses in a local webshop, many Danish webshops have them really cheap.
A quick search on ebay UK shows more than 1300 hits in Europe when I search "glasses myopia"
W-H Guest
Posted
Online yes, I meant for trying temporarily on Monday for Soks 😃
We don't really need it otherwise or do you think we should have couple of them like -1.5 and -1.0 handy?
Guest W-H
Posted
No, there will be no use of minus glasses at all when the other eye is fixed 😃