Prescription for progressives post surgery in one eye

In the 5 weeks between my surgeries, I had about a 4-5D difference between my eyes. I got used to it in most situations. For distance, my brain essentially shut off my near eye and for very near it shut off my far eye. There wasn't any overlap in the distances where both eyes could see decently so I had minimal binocular vision, if any. But I don't think I suffered from anisometropia.

There was a noticeable difference in the size of the objects seen out of my eyes when I had just one surgery. The brain has problems processing when the images are different sizes. I suspect that anisometropia is a much bigger issue when the difference between the eyes is closer to -2D and your brain attempts to use binocular vision. If one eye sees distance and the other near and the brain attempts to use both for intermediate then it would have problems fusing the images.

My near eye wasn't remotely capable of seeing intermediate so my brain learned to ignore it.

That's interesting. With the 1.5 offset glasses it's like either eye's vision is ok but kinda like a film comes over them when using them together.

This is very helpful. I am considering having -1.5 in my second eye instead of plano. Now I am thinking that both eyes plano would make it easier to have the best possible vision with progressives. Because of the remaining astigmatism in the eye that has had surgery, I can see that I will need to wear glasses for the best distance vision, such as for night time driving and even for reading text that shows up on the television that is not a bold font.

The negative effects of glasses with an offset (monovision glasses) is worse than it would be with contact lenses or IOLs. I've done -1.35 in one eye with a contact lens without experiencing the same level of negative impacts.

Your remaining astigmatism might not be as noticeable when both eyes are set for similar distance. It seems that the magic of binocular summation helps with that as well.

Low levels of uncorrected astigmatism have only a small effect on binocular visual acuity under normal binocular viewing conditions. However under monovision conditions, low levels of uncorrected astigmatism have a significantly greater effect on binocular visual acuity. This presumably occurs because of the diminished opportunity for binocular summation under monovision conditions.

That quote is from an older study titled "Binocular summation of astigmatism with reference to monovision".

thanks for this information about astigmatism

Myope here is a question for you and others. Looking at a prescription from my optometrist for glasses, I see the sphere at +1.0. I have assumed that this is the amount by which the glasses are to correct the vision in the eye. If the eye needs +1.0 to see the eye chart the best, does this mean the eye with the iol can be described as 1.0 sphere? It seems more logical to me that the iol is a different number which requires the addition of +1.0 to read the chart to the best possible extent. So how would one figure out the number that describes the iol eye? No one has said my eye can be described as +1.0. What has been said is that the eye needs a prescription with a sphere of +1.0 to see as well as possible. Would you say that +1.0 is the same as plano? The opthalmologist has described the vision with the iol as having a sphere of plano. I am confused by the way in which the numbers are used in our discussions.

The terminology used in this issue of where the eye is can be a bit confusing. The term plano I think can be used somewhat loosely. It can mean that you can see distance well without eyeglass correction, but "well" may not be as well as if you wear glasses. Technically it would mean that both your sphere and cylinder is 0.00. But, when used loosely that may not be the case. Based on your posts so far I have concluded you have the following eyeglass prescription in your IOL eye. I am not sure if it is your left or right, so I will call it your IOL eye:

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IOL Eye: +1.0 D Sphere, -1.0 D Cylinder, 30 degrees Axis, +2.5 D Add

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Technically it would be incorrect to call this eye "plano", as both the sphere and cylinder is off by a full diopter, which is a lot. However, the most important number is the sphere as it is the basic shape of the eye. Based on that number you have been left far sighted or hyperopic by 1 diopter. The complication is that you have also been left with significant astigmatism. Astigmatism is a hourglass or bow tie shaped error that is essentially overlaid on the sphere error. There will be two maximum - error points and two maximum + error points around the eye. The angle to one of the - error point maximums is 30 degrees. What this means is that as you go around the circumference of the cornea at 30 degrees the effective power will be +1 sphere + minus 1 cylinder for a total of 0.0 D. The portion of your eye at 30 deg is "plano". However when you go another 90 degrees to the 120 degree portion the effective power will be +1 sphere, plus +1 cylinder for a total of +2 far sighted. Not good! Since these plus and minus portions of the eye are hourglass shaped there is another minus area and another plus area.

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Now, for reasons I do not totally understand, the convention in the optical field is that the overall spherical equivalent of this is that you add 50% of the cylinder to the sphere to get what is called a spherical equivalent. In your case that would be +1.0 plus one half of -1.0 or a total spherical equivalent of +0.5 D. In other words mildly far sighted or hyperopic. The assumption seems to be that the eye/brain can make use of some of the cylinder minus, while ignoring some of the cylinder plus.

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I would technically not call that plano, but since you have apparently tested at 20/20, you would appear to be functionally plano. That brings up a point. When they tested you at 20/20 was that with correction, or with no correction? If it was with no correction, then I would expect you could get 20/15 with eyeglass correction of the sphere and cylinder.

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Does that help, or further confuse?

with the eye that has the iol, and the other eye closed, I find tht the near vision "slice" on th progressive lens starts too low. So maybe they can adjust that. But the question will be whether the reading slice has to start at the same height for both eyes. It seems likely

I didn't respond initially as essentially almost all of your post was cut off. Thanks to @Myope_PSC I now see the question you were asking.

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I went nearly 1.5 years with one eye corrected with an IOL and the other with good vision but not corrected with an IOL. I initially corrected the IOL eye and the unoperated eye with progressives. While it basically worked and both eyes had good vision, there was something "off" about it. I think the reason is that there is a difference between correcting the vision at the IOL/lens plane and at the eyeglass plane. They both can present an in focus image to the retina, but the image is not the same size. The brain does not seem to like that so much and I suspect it gets worse when the correction amount is higher. I was about -2.5 D for myopic correction and the issue was noticeable, but I suspect it is much more of an issue for someone that is much more myopic in the -4+ range.

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My solution was to correct the vision in the unoperated eye with a contact instead of eyeglasses. Because the contact is much closer to the lens in the eye, the difference is much less and more tolerable. My progressives went essentially unused. I used the opportunity to trial monovision and under corrected the the unoperated eye by -1.25 to -1.5 D.

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Now that I have had the second eye done, I got an updated prescription for the recently operated eye, and got a progressive correction for both eyes. I sent my glasses back to have the lens in one eye updated. My distance eye has zero sphere correction and only 0.5 D astigmatism. The close eye in my monovision has -1.0 D sphere and -0.75 D cylinder for about -1.40 sphere equivalent. Distance vision is definitely crisper with my glasses on. Close and intermediate is good too (+2.5 D add) but with all the associated issues of progressives.

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To answer what I think is your basic question, I don't think there is a difference to the vision with progressive glasses if you correct both eyes for distance with an IOL or if you go for monovision and any correct the close eye to -1.5 D. The eyeglasses will easily handle the difference. But, there will be a difference in what you see without glasses. If you do monovision with the close eye at -1.5 D SE then you are going to see much better without glasses than if both eyes are corrected to full distance. It essentially eliminates the need to carry around readers everywhere you go.

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My recommendation based on my experience would be to correct your second eye to -1.5 D SE, and then get progressives. You will then have two options for vision, no eyeglasses, and progressive eyeglasses. My experience is that I almost never use the progressives, and infrequently use some +1.25 D readers.

Ron -

Is there enough light available when looking through a progressive lens sliver to read ingredients lists in grocery stores or other less-than-optimal lighting? Low-light performance with IOLs is mediocre and viewing through a slices in progressives just seems like it wouldn't work, especially for the larger add values. I'm wondering if I'd be better off with glasses just made for close up (essentially prescription readers). That way more useful light could pass through the lens and be focused on the retina.

You have said you can read with -1.5. I have been told by 2 different ophthalmologists that I will not be able to read with -1.5 in the second eye. I will just have a little better vision so I am more comfortable doing things without glasses, like cooking ....but not reading. So there is something different about my situation than yours. I don't know what it could be. And the readers I need in my eye with the iol at present are +2.5, per my written prescription. With my prescription reading glasses, I can see well until things get closer than about 5 inches, when my vision gets blurred. I hope there is a way to get readers that let you see even closer than that.

I have worn progressives since I was about 45 and I am now pushing 73. I never really had any significant issue getting used to them. There are some tricks to learn, such as not looking down at your feet when on stairs. Don't look, "use the Force Luke!". There is an occasional issue when working on something over your head and close. When you look up then you are looking through the wrong part of the lens. When I was myopic I would just take my glasses off. Now if I had a distance correction in both eyes, I guess I would use some readers.

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Now with monovision I certainly appreciate being able to look up and down without moving my head to see close. But you do get used to it. With progressives it is much better to have a computer monitor sitting as low as possible instead of at eye level.

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I don't find that the viewing area of progressives to like a "sliver" if you have reasonably deep frames. That gives them more room to spread the progression over. For 45 years or so, my "Add" has never changed. It is always +2.5 D. I wondered why it never changed as my eyes changed, until I realized the "add" is as the name suggest an overlay of that power on top of the distance prescription. So in absolute terms the power of it is changing, but not relative to the distance correction.

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I would suggest the main difference between the quality levels of progressives is not in the up down progression of the correction, but in how far it goes sideways in the lens. Cheap progressives can have a very narrow width of close correction. It means you not only have to move your head up and down but also sideways for the best vision.

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Yes, having special full lens close correction is nice to have but only for the distance it is correct for. You still get into the eyeglasses changing thing again. Progressives in my experience are put on in the morning and left on all day.

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With monovision I was worried that standard readers with the same correction in both lenses would not work for me, and I might have to get special readers made. That has not turned out to be the case. When I need better close vision than my approx -1.5 eye gives me I just put on some +1.25 readers. This shifts my distance eye to -1.25 D and the close eye to -2.75 D. It is kind of a close monovision set up, and seems to work. But, looking up and across the room is a no go. I take the readers off as soon as I am done the close work task. There is no way I could tolerate being -1.25 and -2.75 D and without glasses around the house for any time.

I think we have had this conversation before about what is needed for close vision in mini-monovision. My close eye tests at -1.0 D sphere, and -0.75 D cylinder. Unfortunately I did not end up with a clean -1.5 D sphere, which is what I think would have been ideal. On a spherical equivalent basis correction for astigmatism where you add 50% of the cylinder to the sphere, this is a SE of about -1.38. There is no way I could see well at 5"(and really have no need for it), but I can see well at 12" with this eye. This is enough to read almost all text on paper and my iPhone. Super small print requires some +1.25 D readers. With distance in my other eye I am about 95% free of glasses. Weeks will go by without a need for readers. There is nothing special about my IOL or my eyes that lets me do this. I am older at nearly 73 so my pupils will be smaller, but that is about it.

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I see that you have plano in your IOL eye and 20/20 vision. That is very good. Do you have an eyeglass prescription for that eye? That is the most accurate way of determining where it stands. But, lets assume it is 0.0 sphere and less than 0.75 cylinder. If this is the case you can do a simple test to determine how you will see if you target the other eye to -1.5 D. Just buy some Dollar store readers with a +1.5 D correction. When you put them on, that will be a very close simulation of what your close vision will be with a target of -1.5 D for an IOL. Close your unoperated eye so you only look through the readers with your IOL plano eye.

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The Add for progressives is pretty much standard at +2.5 D. Every pair of glasses I have been prescribed have been with a +2.5 add. Keep in mind that the power in the bottom of a progressive has a MAXIMUM of +2.5 D, and you will probably look through them higher up using a less powerful section than the +2.5 D. Testing with the Dollar store +1.5 D readers does not have that complication, and will give you a good simulation of a true -1.5 D target.

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Hope that helps some. If you post your eyeglass prescription I could be more specific with the power to try with the Dollar store readers.

Freddi can I ask you what sort of things you like to see closer than 5 inches and wouldn't you be able to get prescription readers that will let you see pretty much at any

distance you want?

Ron I know you discussed this before but can you expand upon "on a spherical equivalent basis correction for astigmatism where you add 50% of the cylinder to the sphere..."?

Does this mean that half of any residual astigmatism after cataract surgery could in effect be added to the targeted diopter and improve near vision?

Astigmatism essentially has a + and a - component to it. The assumption seems to be that the - portion is somewhat additive to - sphere and improves closer vision. I guess your brain ignores the + component? I strongly suspect that the - effect is not as good as pure sphere -. The practice in setting an IOL target when there is astigmatism involved is to use the SE method and target based on SE.

Prescription for operated eye is:

sphere + 1.0

Cylinder -1.0

Axis 030

Add 2.5

by the way my progressives prior to surgery had an add of 2.75 in each eye.

The Spherical Equivalent of that prescription would be +0.5 D. I am a bit surprised that you have 20/20 distance vision. In any case to approximately simulate -1.5 D vision you would need some dollar store +2.0 D glasses. They would give you a good idea of what your reading vision would be like with an IOL targeted to -1.5 D SE.

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Have you been given an expected astigmatism (cylinder) outcome for the second eye?