IOL Monovison Simulation with a Contact Lens
Posted , 6 users are following.
I am a little over 3 weeks out from my cataract surgery in one eye. My opposite eye has a minor cataract but with eyeglasses I can get 20/20 vision with it. What I have found however is that while I don't have a lot of correction needed for that eye (-1.5 Sph, -1.0 Cyl.), when I wear my eyeglasses with no lens in my cataract surgery eye (20/20 with no correction) I get an odd sensation and feel kind of dizzy. When I wear a contact in my non IOL eye, this effect goes away. So what I am trying is to do is two things as a trial. First I want to find a contact that I can wear for 15 hours a day. And, second I want to simulate monovision by under correcting this non IOL eye. My thinking is that while I still have good vision in my non IOL eye this would be the best time to evaluate whether permanent IOL monovision is a good solution for me when it comes time to do the second eye. I thought I would start a thread here to share my experience and also if others have experience with contacts and/or monovision trials I would be happy to hear it.
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On the contacts subject I have worn soft contacts since 1975 or so, but not much in recent years. I had some on hand that I have never liked as they are hard to put in and get uncomfortable too quickly. They are J&J Acuvue Moist 1-Day lenses. I really hope to find something better. My first try for a better lens has been the Acuvue Oasys 1 Day. It is definitely more comfortable longer than the Moist version. Out of 4 days I made the 14 hour mark once. Today is my first day with an Alcon Total1 lens. It seems pretty good, but I am not half way through the day yet. Both the Oasys and Total1 lenses are easier to put in than the Moist ones. Costco also gave me some B+L Biotrue to try, but I have not yet, and am not all that optimistic about them as they are Hydrogel like the Moist lenses. The Total1 and Oasys are the newer Silicone Hydrogel type. This trial part is going to take some time, but I hope I find something that gives me a full day. I would like to try the Alcon Precision1 lenses, and the B+L Infuse lenses but they are not available at Costco in Canada yet. I see they are in the US though.
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As far as the monovision trial part, I think I pretty much have that sorted out. My non IOL eye prescription converts to a non toric power of -2.0 (spherical + 50% of the cylinder). From that I subtracted what I want to trial for an under correction of -1.5 and -1.25. This becomes -0.5 and -0.75 in a lens. What I have found so far is that the -0.5 gives me better reading, but it leaves kind of a hole in good vision at the computer screen distance. The -0.75 does not let me read very small print, but I can read my iPhone quite well, and the computer screen is quite OK. At this point I am pretty settled on a -1.25 monovision solution, and am quite satisfied with the outcome. Using both eyes I have a fairly easy 20/20 vision, and about half the letters on the 20/15 line. I don't see that much difference between the two under corrections at distance. It is in the intermediate distances that they differ.
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So, I hope this is of some help to others, and I welcome any comments or assistance with my "monovision project".
0 likes, 40 replies
soks RonAKA
Posted
the problem i see with the trial is that the non iol eye with contact lens will still have accommodation which the the iol implant wont. with your numbers it is very likely that your near vision during trial will be a lot better than near vision with a -1.25 monofocal.
good luck.
RonAKA soks
Posted
Yes, that is a concern that I have thought about. The last words I had with the surgeon that did the IOL was about that. I asked if I tell him what contact lens power works for me, can you convert that into an IOL power to give me the same effect. He said yes.
RonAKA
Posted
As a bit of an update I have tried 5 different brand/models of contacts. While I still have some of each left here is my current rating of them:
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Hope that helps some who are using contacts to make do with an IOL in one eye. I think the first three are all worth trying, and the last two, not so much. I get my contacts at Costco and in the US they have the very new Alcon Precision1 lens, but not in Canada. When and if they arrive at my Costco I think I will give them a try too. Until then, I will go with the Kirkland. The Precision1 have specs similar to the Kirkland lenses and a tighter still 8.3 BC. I am thinking they may work well too, and are cheaper than the Total1 lenses. Also note that some of these lenses are spherical only with no toric models available.
RonAKA
Posted
I basically finished my testing of contacts and ordered the Costco Kirkland Daily lenses in the -0.75 power which gives me about a -1.25 D under correction or myopia. As I used up the remaining trial contacts I pretty much confirmed the rating order of them above, except that I would rate the Acuvue Oasys Daily and Alcon Total 1 the same.
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I also tried the remainder of -0.5 power lenses which give me -1.5 D of under correction or myopia. They are really not that bad either. Since one cannot get a correction as exact with an IOL, when that time comes, assuming I go with a monofocal lens, I will ask for an under correction that puts me between -1.25 and -1.5 D. I'm pretty sure I can accept anything in that range of monovision. For sure I will still need reading glasses for the very fine print. When I get near to the end of the 180 Kirkland lenses I've ordered, I may do a trial of the -0.5 power contacts again to see if I am more tolerable to that much anisometropia. It would seem one should have neuroadapted as much as I am going to by that time.
RonAKA
Posted
Another update. I am coming to the end of my initial supply of -0.75 non toric Kirkland contact lenses. They have worked very well for me in simulating monovision. But, before I order more I wanted to try a toric lens to see if I could get better vision with my left nearer vision eye (not IOL yet). Stopped today at Costco and picked up some trial toric lenses, Acuvue Oasis 1-Day for Astigmatism.
My eyeglass prescription:
Spherical -1.25 D, Cylinder -1.25 D, Axis 77
The lens I got to simulate -1.25 D monovision:
Spherical 0.0 D, Cylinder -1.25 D, Axis 80
My first impression is that there is an improvement over my -0.75 D Kirkland non toric lenses. Distance seems to be a little better and reading is a little better. In bright light I can see J2 easily and J1 with a little more difficulty. The only issue is that the Acuvue lens does not seem to be quite as comfortable. They are a little stiffer than the Kirkland (CooperVision 1 Day), and have a slightly different curvature. Perhaps will get used to them with more wear.
In any case I think I have already determined what I was mainly wanting to know which is that an astigmatism reduction which I hope to get with the cataract surgery may give me better monovision, and not worse.
Dapperdan7 RonAKA
Posted
ron, it seems amazing that there is no model of capitalism that allows someone to experiment with different brands, types and prescription optics of contacts lenses without BREAKING THE BANK. i am going to costco next week (per your recommendation) going to try mini monovision. UNLESS i can find a doctor who will let me try this experiment a bunch of times (not sure how likely these days) i have to get the first or second choice pretty close to correct.
question, since i assume there is more precision with an contact than an IOL ,should i not get one eye set for plano (as opposed to undercorrection in surgical situation) and then the other in the 1.25-1.50 range?
as always thx. these threads really are educating me!
RonAKA Dapperdan7
Edited
It may vary from country to country, and also from optical supply place to another, but in general I believe the manufacturers like Alcon, J&J, and CooperVision provide these optical supply places with free sample contacts typically in packages of 5 lenses. They should not sell these trial packages and I believe there is a warning on them that they are not intended for sale, just a free trial. So a cooperative optical outlet should be quite willing to give you a trial package for each eye.
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There is no need to target a -0.25 D for the distance eye like you would with an IOL. The contact should perform as they are marked. The only bit of an adjustment is that with a higher power lens like yours at -6.50 D for eyeglasses there will be a small adjustment in going from an eyeglass prescription to a contact lens prescription. On a quick check if there is no astigmatism it converts to -6.00 D in a contact. This is because the lens sits closer to your natural lens with a contact, compared to the lens in eyeglasses. In any case CooperVision has an online calculator to convert from eyeglass to contact prescriptions. You should find it if you google this.
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CooperVison OptiExpert Contact Lens Prescription Calculator
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On the near eye only reduce the sphere component by 1.5 D after you get the required value from the calculator. Keep in mind that they do come in power increments of 0.25 D like glasses, the angle of the astigmatism unlike glasses is not provided to the exact degree. The calculator will determine which of the available angles is closest and best for your correction.
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If you can provide your exact eyeglass prescription for sphere, cylinder, and angle for each eye, I can run the calculator and give you what it recommends for that prescription along with the reduction in the near eye for monovision. Also do you know which eye is the dominant eye?
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One thing to keep in mind is that at least at the Costco I go to, there can be a significant difference in the skill/knowledge of individual contact lens fitters. If you get one that is not so cooperative come back another day to get someone different.
Dapperdan7 RonAKA
Edited
this is from 3/15/2022
OD -6/+1.50 175 /+2
OS-6.5/+1.00/005/+2
i beliece my left eye is the dominant based on the finger in front of the eye test. im left handed if that means a damn thing.lol
would i get the toric contact exam with my astigmatism?
thx much
RonAKA Dapperdan7
Posted
This is what OptiExpert gives for a conversion from eyeglasses to contacts. The other complication here is that you must have gotten this prescription from an ophthalmologist, and not an optometrist? Ophthalmologists express astigmatism in positive numbers and optometrists do it in negative terms. The conversion is a little wonky. To convert you add the sphere and cylinder together while respecting the signs to get the optometrist sphere. The cylinder sign just flips to negative. And 90 degrees is either added or subtracted to the angle to stay between 1 degree and 180 degrees.
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OD Right Eye (assumed non dominant)
Glasses: -6.0 D sphere, +1.50 D cylinder @ 175 deg (ophthalmologist convention)
Glasses: -4.5 D sphere, -1.50 D cylinder @ 85 deg (optometrist convention)
Contact: -4.25 D sphere, -1.25 D cylinder @ 80 deg (full distance correction)
Contact: -2.75 D sphere, -1.25 D cylinder @ 80 deg (-1.50 monovision)
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OS Left Eye (assumed dominant)
Glasses: -6.5 D sphere, +1.0 D cylinder @ 5 deg (ophthalmologist convention)
Glasses: -5.5 D sphere, -1.0 D cylinder @ 95 deg (optometrist convention)
Contact: -5.25 D sphere, -0.75 D cylinder @ 100 deg (full distance correction)
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This was more complicated than I expected to make the conversions, and I hope it is correct. You should of course get the contact lens fitting tech to check the numbers. I suspect they have a computer to do it. Make sure they get the conversion from + cylinder to - cylinder correction right.
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I am not sure what you were meaning by this question?
"would i get the toric contact exam with my astigmatism?"
Dapperdan7 RonAKA
Posted
am i to assume costco does not employ an optometrist for the 150$ price? seems pretty high.
they offer a higher priced toric contact lens exam. would i choose that exam since i have an astigmatism?
RonAKA Dapperdan7
Edited
It sounds like you must have made an appointment for an eye exam with an optometrist at Costco. I have an independent optometrist that I get an annual exam with and do not use the optometrist service at Costco. My regular optometrist receptionist often asks me if I wear contacts, and I always say no, as their prices for contacts are high. But, I always ask for a written prescription for eyeglasses. Then I take that prescription to the Costco optical supply desk (not the optometrist) to buy either eyeglasses, which are 1/3 to 1/2 the price that my optometrist wants, or to buy contacts. Where I am, as long as you have a valid eyeglass prescription that is less than a year old, you do not need to see an optometrist at Costco. You just go to the optical supply desk with your prescription and ask to do a contact lens trial. If they are not too busy they will take you right then, and if they are busy they will make an appointment. There is no charge for this service. If you are some distance away from Costco, it would be best to make an appointment for the contact lens trial. Tell them you already have a prescription and don't want to see an optometrist.
Dapperdan7 RonAKA
Posted
ahhhh..thank you. i will do that! my prescription is 10 months old
Dapperdan7 RonAKA
Posted
but, can i get a toric lense sample or do i then need an appt w optomitrist? or would u recommend doing the trial w/o the toric?
Dapperdan7 RonAKA
Posted
one more question.
since an exam for contacts is more expensive and i assume a different exam , dont i need a contact lens before getting contacts? confused
thx
dan
RonAKA Dapperdan7
Posted
If your glasses that have this prescription are doing a good job of correcting your vision, I would not bother with an optometrist exam just to do a contact lens trial. To my knowledge there is no special exam for astigmatism. It is part of a normal eye exam and writing a prescription for glasses. The prescription you have includes a correction for astigmatism. That is the cylinder number and angle. Your astigmatism corrections (in optometrist format) are:
Right eye:-1.50 D cylinder at 85 deg.
Left eye: -1.0 D cylinder at 95 deg.
This is all that a contact lens tech at Costco should need to prescribe a toric contact that corrects for astigmatism as well as the sphere. I have never had to get any special exam for a toric contact. I just use my standard eyeglass prescription. The contact lens fitting tech should be trained to make the conversion from an eyeglass prescription to a contact lens prescription, and also should be smart enough to make the further correction to simulate a -1.5 D monovision for a near eye.
Dapperdan7 RonAKA
Posted
hey ron, did u say you were in canada?
i stopped off at the wal mart vision center here and asked the employee if i could get contacts with only an eyeglass prescription and she said no. they would need base curve and something else so i would have to pay for a contact lens exam. so i wonder how you were to get the trial lenses a regular prescription for eyeglasses.
as always...thank you
RonAKA Dapperdan7
Edited
It sounds like you are getting the run around. At least here in Canada, Costco does not do that. I have never tried to buy at Walmart, so don't know about them.
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The process that Costco uses here is just trial and error. The fitter has no way to measure your eye, and the range of BC values of lenses is very limited (8.3 to about 8.6). One brand and type is typically only available in one size. It is kind of a take it or leave it thing. They just put a lens in to see how it fits on your eye. You blink and they check to make sure it stays centered on your eye. I have tried various different lenses and they gave them all the thumbs up. They basically left it to me to decide if I liked them or not. The game may be played differently in the US, but my experience here with Costco is that they are happy to do this trial and error fitting at no cost. Remember that they get trial contacts from each manufacturer at no cost. It is like the food samples they hand out. The cost of those is paid by the supplier of the product.
It is probably best to go to a Costco and talk to them directly at the optical supply side of the business that does the glasses and contacts. Things may be different in the US.
Dapperdan7 RonAKA
Posted
ok. will do.
thx
jimluck Dapperdan7
Posted
I just emailed my ophthalmologist, told him what I wanted to do, and asked him to do a prescription to Walmart for soft contacts. He did. No charge. He guessed at the base curve and noted on the prescription that if I wanted a different base curve that was okay too. Not all doctors would be that helpful, of course.
I got the lenses. They didn't work for me, but that's a different story.
RonAKA Dapperdan7
Edited
Out of curiosity I went back to my contact lens comparison spreadsheet to see what the specs are for BC and diameter. This is what I found for the toric lenses I suggested trying.
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As you can see there is not much difference between them. I would suggest the other properties of the lens are much more significant than the BC or diameter.
Dapperdan7 RonAKA
Posted
so costco wont fit for contacts unless i get the exam so im on the hook for 150 fee.oh well.
RonAKA Dapperdan7
Posted
That is sure different than the way they operate in Canada, but I guess in the scheme of things it is a relatively small cost to get prepared for cataract surgery down the road. And, you will get the best up to date prescription for contacts to do a trial with.
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Perhaps part of the difference is because of regulations we have here. An optometrist cannot both do eye exams and also sell glasses or contacts. While there are many optical businesses that have an optometrist, there will almost always be an optical dispensary at the same site. Behind the scenes the eye exam part has to be a legally distinct business from the optical dispensary. The optometrist business is obligated to provide a prescription for the eyeglasses but cannot sell you the eyeglasses or contacts. It is kind of an odd arrangement, but it lets the customer shop around for glasses and contacts without being stuck to buy from the optometrist. Here at least it lets anyone with a prescription to shop where they want to buy glasses or contacts.