Aa
Glasses equivalent to monofocal IOL - cataract
Hello!
I am a 60 years old architect spending most of working time behind computer or with pen and paper. In 2017 I was diagnosed early cataract in both eyes. During the time that followed I developed a bit cloudy central vision on my left eye and nigh times became much darker than ever before to me. Obvious effects of the cataract. Since then, with everyday use of Can-C eye drops I managed to clear my left eye and to maintain relatively crisp vision in both eyes, while researching on IOL (and postponing decisions :).
A month recent eye test result:
R sph +1.75, cyl -0.25, axis 180; reading add +2.0, intermediate add +1.25
L sph +1.75, cyl -0.25, axis 55; reading add +2.00, intermediate add +1.25
My ophthalmologist had diagnosed cataract stage 2 and referred me to NHS for surgery.
Now, doctor in Moorfields Hospital, London, UK challenged my idea about choice of IOL. In the past years I visited three private eye hospitals to gather some knowledge and opinions. Mostly I've heard recommendations for multifocal IOL. This time the Moorfields doctor recommended monofocal as the one next best to natural vision, explaining all of the pros and cons, to which I agree. I don't mind wearing glasses for reading and computer as long as they give me better vision than without glasses with IOL, but I do not like to wear glasses outside in open or when driving, which with cataract evolving it is becoming more disorienting and confusing.
I put decision on hold and meanwhile have made two pairs of distance glasses; one with Cyl powers and one without. The reason for making this glasses was to mock-up the situation of monofocal IOL.
My question is : Can glasses mock-up vision given through IOL at all? My main concern here is astigmatism which is not large but it does affect my vision.
Here in the UK NHS is only installing monofocal lenses and toric lens for astigmatism only above I think 2 which my eyes don't come under. So if I am to take toric lens, which I am considering the surgery would have to be done at private care.
Also, would aspheric type of lens here give any additional vision improvement?
Many thanks for your answers.
I am a 60 years old architect spending most of working time behind computer or with pen and paper. In 2017 I was diagnosed early cataract in both eyes. During the time that followed I developed a bit cloudy central vision on my left eye and nigh times became much darker than ever before to me. Obvious effects of the cataract. Since then, with everyday use of Can-C eye drops I managed to clear my left eye and to maintain relatively crisp vision in both eyes, while researching on IOL (and postponing decisions :).
A month recent eye test result:
R sph +1.75, cyl -0.25, axis 180; reading add +2.0, intermediate add +1.25
L sph +1.75, cyl -0.25, axis 55; reading add +2.00, intermediate add +1.25
My ophthalmologist had diagnosed cataract stage 2 and referred me to NHS for surgery.
Now, doctor in Moorfields Hospital, London, UK challenged my idea about choice of IOL. In the past years I visited three private eye hospitals to gather some knowledge and opinions. Mostly I've heard recommendations for multifocal IOL. This time the Moorfields doctor recommended monofocal as the one next best to natural vision, explaining all of the pros and cons, to which I agree. I don't mind wearing glasses for reading and computer as long as they give me better vision than without glasses with IOL, but I do not like to wear glasses outside in open or when driving, which with cataract evolving it is becoming more disorienting and confusing.
I put decision on hold and meanwhile have made two pairs of distance glasses; one with Cyl powers and one without. The reason for making this glasses was to mock-up the situation of monofocal IOL.
My question is : Can glasses mock-up vision given through IOL at all? My main concern here is astigmatism which is not large but it does affect my vision.
Here in the UK NHS is only installing monofocal lenses and toric lens for astigmatism only above I think 2 which my eyes don't come under. So if I am to take toric lens, which I am considering the surgery would have to be done at private care.
Also, would aspheric type of lens here give any additional vision improvement?
Many thanks for your answers.
MEDICAL PROFESSIONAL
Wearing glasses before surgery with and without cylinder lens does not give a good approximation of post op vision because you are looking through visually significant cataracts in each eye. Let me assume money is not a problem. Assuming you can find an experienced surgeon, the world state of cataract surgery is Light Adjusted Lens (LAL). They correct large amounts of astigmatism and the post opertive refractive error can be adjusted to the patients liking and then 4-6 weeks post op can be 'set' and become permanent. If I were having cataract surgery that is what I would do not, however I don't need surgery now. The second best vision without glasses would be a toric IOL with post op power set for mini-mono distance bias or near bias. Multifocal IOLs with and without toric corrections are highly prone to unhappy patients. Our practice no longer uses them instead doing the LAL. A spherical IOL should give you improvement because most important the cataract has been removed. You would need to decide what option you wanted without glasses distance bias or near bias. Your best vision of course will come with glasses on for distance and near. (progressive bifocals)
4 Comments
I suspect what you really want to find out is how your close and intermediate vision will be with monofocal lenses set for distance. If your cataracts are bad in both eyes that will be hard to determine due to the blurry vision from the cataract itself. However if at least one eye has vision that is correctable to 20/20 visual acuity (6/6 in UK I think) or close to it then your distance eyeglasses will be a good approximation. The only caveat is that at age 60 you are likely to still have some accommodation and it will be somewhat optimistic.
Hello again doctor John C Hagan. I am glad to find you still here on MedHelp platform. Thank you very much for your answers. I am at the stage where every question asked opens another "can of worms" and is shifting me further from decision. Your challenge with LAL technology suggestion came welcome here and I started looking into it. It seems so far there are no many practitioners in the UK who are doing LAL procedures. Perhaps in a year or so when I am planning my operation the situation will be different. Many thanks again.
You are welcome.
The best simulation of a monofocal IOL with eyeglasses is to use lenses set for distance only, not bifocals or progressives. This is not a perfect simulation as at age 60 you will still likely have some accommodation (ability to focus nearer). The IOL lacks that ability.
An IOL set for distance of course will give you good distance vision providing the surgeon hits the target for correction. And most people will see well down to 2 to 3 feet, and then it starts to get blurry. Most see their car dash well. Readers are needed for near vision though. You do not have to target them for distance and they can be set for -2.0 D which will allow near vision but you will need glasses for distance and driving. Vision would be very similar to what you have now without glasses.
Have you had your eyes measured to determine what the estimated astigmatism (cylinder) will be after surgery assuming no toric correction? That is the only way to decide if a toric IOL is worth it. The eyeglasses cylinder you have now is the result of astigmatism in the cornea plus in the lens, and the impact the cataract is having on the lens. The astigmatism in the lens will be gone after cataract surgery as the whole lens is replaced with the IOL. So what you need to know is the astigmatism in the cornea which will remain. As I understand it NHS will not provide a toric lens so they may not do the measurement (typically a Pentacam) to do the cornea astigmatism. You may have to pay extra for that or get it done at a private clinic. The reason I say this is that 0.25 D of cylinder is a very small amount and if that is your cornea astigmatism too small to be corrected with a toric lens. The minimum toric correction with an IOL is about 0.75 D, and if you used that with only 0.25 D or cylinder it would be an over correction and make your astigmatism worse not better.
I think monofocals are a good idea if you want artifact (halos and flare) free vision. And you can achieve 95% eyeglasses free vision with monofocals if you use mini-monovision. One eye is targeted to distance and the other eye to near (typically -1.50 D). That is what I do and while I have progressive glasses I virtually never wear them. I do use some +1.25 D reader occasionally, but never carry them with me. They sit on my desk for the odd task with very small print in dim light. If you want to go down that route it is best to do the first eye with a monofocal for distance and then simulate monovision with a contact in the other eye while your operated eye recovers. If you like it then you can get the second eye done for say -1.50 D. If you do not, then you could carry on and get the second eye done for distance as well.
Here is an article by Dr. Barrett who is a world recognized expert in IOL power calculation methods. I agree with his thinking on mini-monovision except that I determined the -1.25 D in the near eye was not enough for me and targeted -1.50 D instead. I have actually ended up at about -1.60 D.
https://crstodayeurope.com/articles/2009-oct/1009_12-php/
Most monofocals today are aspheric correcting. Some like the Tecnis 1 fully correct all positive asphericity. The Alcon Clareon or AcrySof IQ correct about half of it. The B+L enVista is called asphericity neutral and corrects none of it. There are pros and cons to both ways. The Tecnis 1 provides the best distance vision providing the target it hit. However it gives the least depth of focus. The enVista does not give quite the same visual acuity but the most depth of focus (ability to see nearer). I think either the Clareon or enVista are good choices if they are available to you.
An IOL set for distance of course will give you good distance vision providing the surgeon hits the target for correction. And most people will see well down to 2 to 3 feet, and then it starts to get blurry. Most see their car dash well. Readers are needed for near vision though. You do not have to target them for distance and they can be set for -2.0 D which will allow near vision but you will need glasses for distance and driving. Vision would be very similar to what you have now without glasses.
Have you had your eyes measured to determine what the estimated astigmatism (cylinder) will be after surgery assuming no toric correction? That is the only way to decide if a toric IOL is worth it. The eyeglasses cylinder you have now is the result of astigmatism in the cornea plus in the lens, and the impact the cataract is having on the lens. The astigmatism in the lens will be gone after cataract surgery as the whole lens is replaced with the IOL. So what you need to know is the astigmatism in the cornea which will remain. As I understand it NHS will not provide a toric lens so they may not do the measurement (typically a Pentacam) to do the cornea astigmatism. You may have to pay extra for that or get it done at a private clinic. The reason I say this is that 0.25 D of cylinder is a very small amount and if that is your cornea astigmatism too small to be corrected with a toric lens. The minimum toric correction with an IOL is about 0.75 D, and if you used that with only 0.25 D or cylinder it would be an over correction and make your astigmatism worse not better.
I think monofocals are a good idea if you want artifact (halos and flare) free vision. And you can achieve 95% eyeglasses free vision with monofocals if you use mini-monovision. One eye is targeted to distance and the other eye to near (typically -1.50 D). That is what I do and while I have progressive glasses I virtually never wear them. I do use some +1.25 D reader occasionally, but never carry them with me. They sit on my desk for the odd task with very small print in dim light. If you want to go down that route it is best to do the first eye with a monofocal for distance and then simulate monovision with a contact in the other eye while your operated eye recovers. If you like it then you can get the second eye done for say -1.50 D. If you do not, then you could carry on and get the second eye done for distance as well.
Here is an article by Dr. Barrett who is a world recognized expert in IOL power calculation methods. I agree with his thinking on mini-monovision except that I determined the -1.25 D in the near eye was not enough for me and targeted -1.50 D instead. I have actually ended up at about -1.60 D.
https://crstodayeurope.com/articles/2009-oct/1009_12-php/
Most monofocals today are aspheric correcting. Some like the Tecnis 1 fully correct all positive asphericity. The Alcon Clareon or AcrySof IQ correct about half of it. The B+L enVista is called asphericity neutral and corrects none of it. There are pros and cons to both ways. The Tecnis 1 provides the best distance vision providing the target it hit. However it gives the least depth of focus. The enVista does not give quite the same visual acuity but the most depth of focus (ability to see nearer). I think either the Clareon or enVista are good choices if they are available to you.
1 Comments
Thank you very much Ron_AKA for your detail answer and explanations. My apologise for the late response.
"Have you had your eyes measured to determine what the estimated astigmatism (cylinder) will be after surgery assuming no toric correction?"
No I haven't neither I was aware of it, but thank you for mention, next time I am in an eye hospital this will be a topic for discussion. Your tips for monofocal mini-monovision are also very appreciated. At the moment I feel uneasy with this option as I like to focus through one eye only from time to time, somehow from this knowledge my grasp says that mini-monovision might be confusing for me. The more questions I ask the further I drift from decision. I guess the learning curve is quite a long one when it comes to IOL's. However, many thanks for your clarifying answers.
"Have you had your eyes measured to determine what the estimated astigmatism (cylinder) will be after surgery assuming no toric correction?"
No I haven't neither I was aware of it, but thank you for mention, next time I am in an eye hospital this will be a topic for discussion. Your tips for monofocal mini-monovision are also very appreciated. At the moment I feel uneasy with this option as I like to focus through one eye only from time to time, somehow from this knowledge my grasp says that mini-monovision might be confusing for me. The more questions I ask the further I drift from decision. I guess the learning curve is quite a long one when it comes to IOL's. However, many thanks for your clarifying answers.
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