Recommendation for upcoming cataract surgery

Thanks a lot David for your reply.

0.3 and 0.5 are my current best corrected visual acuity (BCVA) on left and right eye in linear scale. This translates to 20/63 on left eye (which is up for operation) and 20/40 on right eye.

I will ask my doctor about why they chose the sensar lens. So thanks for pointing out some of its characteristics.

Night vision is important as I currently find low light conditions difficult to cope with.

are you saying the glasses are "optical surfaces to generate glare"? explain please

The glasses can be progressive or bifocal.

Yes. I mentioned that at the end of the same paragraph. The point is everyone (doctors included) thinks the objection is to wearing glasses. It's not. Not exactly. I've worn single vision glasses my whole life. I don't care about wearing glasses. The issue is the constant mode switching in certain scenarios once you become presbyopic either due to age or getting an implant.

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I experienced that last weekend doing some body repair on my car. The constant switching between intermediate to do the grinding, masking, painting vs. near vision to see the area in detail, read instructions on products, read grit numbers on sandpaper, etc… was a huge pain. I had to be constantly swapping what glasses I was wearing.

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Another example is when I'm doing night activities with Search and Rescue switching between seeing where I'm going and reading my notes, or compass or GPS. These are the situations that are a pain, not using the computer… because computer use is in one place (I leave the glasses on my desk) for prolonged periods (I'm not frequently switching tasks).

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Young people who still have accommodation before surgery may fail to fully appreciate that. And yes progressives are a good option but they're not perfect and not everyone can adapt to them. And they can be very expensive. I'm between surgeries so I don't want to spend money on those yet… and again, getting properly made ones can be expensive (don't ever buy progressives online).

I agree that progressives are very annoying when doing auto work or any situation where you have to look up at close objects. It forces you to look through the top of the lens which only has distance correction. Now with mini-monovision I only use safety glasses to keep the dirt out of my eyes.

are you saying the glasses are "optical surfaces to generate glare"? explain please

You have seen reflections in eyeglass lenses. That light goes places. It will reduce the available light, but can also provide artifacts other than a dimming.

Many TV shows have the actors wear glasses frames with no lenses.

If the lenses are not perfectly clean, this increases the artifacts.

"The issue is the constant mode switching..."

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Yes, that is exactly what I am trying to avoid.

• Putting on glasses, then taking them off
• Switching from reading to progressive glasses, and vice versa
• Needing to carry one or more pairs of glasses with you
• Misplacing a pair of glasses, and needing to hunt for them
• Losing your glasses and replacing them

It just seems like a giant hassle. I recently had a visit from my brother, and saw him misplace his glasses as soon as he arrived, and then spend a week with three pairs of glasses strewn about the house, constantly switching between glasses on and off or tilting his head this way or that, for computer work, driving, and other tasks. And even that was not enough - when he washed dishes (he is a model guest!) they ended up filthy because he was not wearing his reading glasses and could not see well enough to determine when they were clean. That is no way to live, if you don't have to.

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I have no problem keeping a pair of glasses in my car for driving, so long as I can spend the other 98% of my life not fiddling with eyeglasses.

Thanks Ron and David. I will read more about mini-monovision. I have noticed that you have made a very good post on the same. Does mini-monovision ensures good night vision?

I drive in the city with street lighting without eyeglasses and just mini-monovision. When I drive in the country with no street lighting I feel safer using my progressive glasses that corrects both eyes to plano. That is about the only time I use my progressive glasses.

did you do mini monovision?

I got monovision in 1995 via LASIK. I have not had my first cataract surgery yet, but it's coming up soon. I am planning to retain my monovision with a new artificial lens.

I assume those are logMar values with 0.3 being about 20/40 and 0.5 about 20/60? And if that is with cataracts that is not too bad. No red flag there.

I had suspected they were the numbers in the Digital column of the last table of the Wikipedia "Visual acuity" article.

I am not familiar with the Sensar lenses but your surgeon may have picked them because they are available in very low powers and even negative powers. A very rough estimate of the power needed for -15 D eyes would be a +1 D power. Most IOLs only go down to +5 D. The Sensar AR40E (uppercase E) goes from +2 to +5.5 D, so may be still a little too much. the Sensar AR40M goes from -10 to +1.5 D, so that may be needed. Have you had your eyes measured yet? If so, the surgeon will know what power is needed. Another alternative would be an Alcon AcrySof lens that is available in those low power values. The MA60MA is listed for -5.0 to +5.0 D.

Good point. No toric available for those?

Not sure if torics are available in these very low power ranges.

Hi Ron

I will try to reply point by point as you have made some very good points.

1. I am only going for my left eye currently and as you suggested will continue to use contact lens in my non-operated eye. I am currently also using contact lenses in both eyes.

2. The 0.3 and 0.5 are my current best corrected visual acuity (BCVA) on left and right eye in linear scale. This translates to 20/63 on left eye (which is up for operation) and 20/40 on right eye on Snellen Chart. This visual acuity is with glasses/contact lenses (Since I am highly myopic, I don’t see much without glasses/contacts).

“That is the normal add for progressive or bifocal glasses and provides very good near vision. You will of course need eyeglasses for distance and driving. However, they will be much thinner and lighter than the glasses you have now. A third option is mini-monovision where the dominant eye is corrected to distance (-0.25 D), and the non dominant eye to -1.50 D. Together you can have good vision from about 1 foot out to infinity, if the targets are hit.”

a. If I go for the second option (correction for near vision), will the glasses that I will need for good distance vision ensure good night vision as that is quite important for night driving.

b. Same question for third option. Will mini-monovision ensure good night vision or are there any factors that I should be aware of.

c. Alternatively, if I go for distance vision, will I have poor night vision for near vision situations like reading (or being) in low light, walking in dark etc, as this is what I experience currently and find very uncomfortable. And how do people deal with that.

4. If I go ahead with current plan for distance vision and if that misses the target dur to really long eyes in my case, then can you summarize what can be the implications.

   My eyes have been measured and in doctor’s notes I can see the following:

IOL proposal IOL: J&J AR40E (located in the back)

Diopter: -2.5

Expected refraction: -0.47

The first one is IOL choice but I am not sure about what is meant by Diopter and Expected refraction. May be I should consult him on this and also find out what formula has been used.

Lastly, I would also like to let you know that I have very long eyes (32 mm) if that is of any help in this discussion.

3 a

If you correct to near vision in the -2.5 D range you should get very good night vision with eyeglasses. I am thinking your current issues are due to cataracts. If there are other issues then vision might not improve as much as expected. If you only have a cataract in one eye, it would make me think there may be other issues associated with the very high myopia.

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3 b

Mini-monovision without glasses is unlikely to give quite as good vision in the dark. With glasses it should be just as good as the near vision solution.

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3 c

If you have distance vision you will need reading glasses or progressives for near vision. Vision should be good with appropriate glasses.

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4

A miss with distance vision will mean you will need eyeglass correction for both distance and near. Progressives would be the best solution.

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I suspect the Diopter -2.5 is the power of lens they are predicting. That is a bit more negative than the +1 I guessed at. And based on the range I found on line for the lenses it would require the AR40M lens and not the AR40E, but perhaps what I am looking at is not currently accurate. The expected refraction is the predicted eyeglass correction you will need to get full distance vision. This is a reasonable amount under 0.0 plano. In theory it should get you close to 20/20 vision unless there are other issues with the eye.

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I think your single biggest issue is accuracy of predicting your power needed. For sure you should ask what formulas are being used and why. The article below suggests the Barrett Universal II is the most accurate for eyes with axial length greater than 30 mm. This paper is from 2019 and the Hill-RBF 3.0 formula is much newer than that and may be good to. As minimum ask to see the predictions of the Barrett Univeral II and the Hill-RBF 3.0. The Hill formula is AI based and has been recently updated with new data. It is said that it will warn you if the eye dimensions are outside of the range it is accurate for.

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https://pubmed.ncbi.nlm.nih.gov/30876784/

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You can go as far as asking for the detailed IOL Calculation sheet which will have the eye measurements on it. There is another recent thread here where I posted links to the IOL formula calculators on line. With the detailed eye measurements you can enter the data yourself and do the calculations with the various formulas. Here is a link to the formula thread.

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https://patient.info/forums/discuss/iol-power-calculation-formulas-805028

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I like the mini-monovision option, but with the issues in predicting a power I think the -2.5 D near vision option is safer. With mini-monovision you need to get both eyes close. With the near option if you get one of two close you should get good eyeglasses free near vision. Either option is correctable with eyeglasses so you don't paint yourself into a corner.

"There are some good calculation formulas like the Hill-RBF 3.0 and I believe one of the Barrett formulas is suitable for long eyes (high myopia)."

I also see some research indicating that the ORA system (Optiwave Refractive Analysis) is superior to preoperative biometry formulas for long eyes. It might be worthwhile to consult a doctor about whether ORA could be helpful in this case.

I recall two contributors here that had ORA. In one case it turned out to be a benefit and the other, it did not, if my memory is right. I also believe that it is hefty add on cost.

Hi Ron

If you only have a cataract in one eye

I have cataract in both eyes but it has not progressed that fast in the other eye.

You can go as far as asking for the detailed IOL Calculation sheet

That is a good suggestion. I will ask the doctor to provide me that and will also try to learn from him more about what formula has been used.

A miss with distance vision will mean you will need eyeglass correction for both distance and near. Progressives would be the best solution.

This is my biggest worry, I dont want to be in a situation where I need two glasses. Do you have any suggestion on what is safer; to go for near vision or for distance vision, such that even if it is a miss, I only need one pair of glasses.

I am based in Denmark, so all this is part of public system, which means that state will bear the cost. But may be that also affects the choices one have with regards to lens and whether ORA is an option or not.

I will investigate more on this.

The IOL Calculation sheet should detail the lens they plan to use, the formula they are using, the exact axial (AL) of your eyes, as well as the predicted refraction for each power of lens considered.

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No matter which way you go, progressive eyeglasses will be a single eyeglass solution.

ORA may be an option. It is a process/instrument sold by Alcon. I think for your eyes the Sensar lens is a good choice. You may need the meniscus version of it, which requires some special consideration.

Do you have any suggestion on what is safer; to go for near vision or for distance vision, such that even if it is a miss, I only need one pair of glasses.

Reading glasses are cheap and are widely available.

ron, can you explain low and negative power lens? and are we talking about the power needed to get him close to plano? wouldnt that be considered high power to get his eyes from -15 to near plano? justtrying to understand the terms better.

thank you

lucky guy. i will need to pay thousands out of pocket here in the good ol usa

IOL power is confusing. In a perfect eye the natural lens has a power of about +18 D. So if an IOL is placed in the eye of a person that needs no eyeglass correction the power will be about +18. It is like the 0.0 D of an eyeglass lens.

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In the case of myopia the cornea is too steep and the eye too long. This results in the cornea focusing the light short of the retina. To correct that an IOL power less than +18 is used. The more myopia and the longer the eye, the lower the power of the lens. Most IOLs are available from +5 to +30. But, in those that have very high myopia even +5 D is too much. For that reason there are lens powers that go lower, and even negative.

ok maybe i can understand by explaining. correct me if i am wrong. when he mentions diopter -2.5 (power of lens as you mentioned) and expected refraction of -.47 that is low power since he would be aiming for distant vision, correct? and if he wanted both eyes set for near, he would need "high power lens". is this correct?

thank you again

i think i understand. the longer the eye, the lower the power needed to give him plano. does that also mean he needs a lower power to get -2.5 refraction than someone would with a shorter axial length (or whatever is causing myopia)?

yeah, its confusing that the power or iol lens and refraction are both expressed in diopters. would you agree?

Another way to think of it is, the more powerful your eye is (i.e. seeing close up) the less powerful the implant had to be to get you to plano.

Yes, way different. A person with normal plano vision before surgery would need something like a +16 D IOL to get -2.5 D.

by saying the "more powerful", you mean the more myopic?

if so, thats deeply confusing to me since a more myopic eye i would assume needs more "power" to get to plano. can you explain a little more? does the removal of the natural lens with it up to 18 diopter refraction ( depending on age) have anything to do with all this?

i reread rons explanation. i think i understand there is an inverse relationship between the + # on the iol power and the negative number of the refraction.. ie +18 to get a perfect eye to plano as opposed to a lower strength if we wanted to give that person some myopia

and as an example, what would a person say -5.25 need in an iol to get to that -2.5? would it be a greater power like +18 in an iol?

i think im getting it slowly lol

I misled you with this post:

"Yes, way different. A person with normal plano vision before surgery would need something like a +16 D IOL to get -2.5 D."

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I got it backwards. A plano refraction would need something like a +20 D lens to end up -2.5 D myopic. It is confusing!

The issue is that a myopic eye is too powerful which is what bring the light to a focus, short of the retina. You need a lower power lens to "undo" some of the power.

got it.

and can you answer 2nd half of question with the example of how powerful an iol needed to get a-5.25 eye down to -2.50?

longer axial length (myopia) means higher power to get to -2.50 (such as +22 or something)?

Using the old formula the IOL power to correct to -5.25 D to plano would be:

+18 +(-5.25 x 1.25) = 11.5 D

If you want to be left with -2.5, the power would be about 3 D higher, to leave you with more uncorrected myopia.

I misled you with this post:

"Yes, way different. A person with normal plano vision before surgery would need something like a +16 D IOL to get -2.5 D."

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I got it backwards. A plano refraction would need something like a +20 D lens to end up -2.5 D myopic. It is confusing!

I agree that it can be confusing. If an 18 D IOL gives plano, to go -2D nearsighted you would need to add "-2" to that 18, which would give +16D.

is not the axial length the most origin of myopia? so how is "too powerful" explained??

If you think about a thick lens being more powerful, the longer the eye, the thicker the lens. It is worth keeping in mind that this formula is very crude. It is a method of estimating the axial length of the eye based on the total refraction before surgery and before the influence of cataracts in the lens. It is the combined effect of the lens and cornea. However it does not distinguish between the relative contribution of each part of the eye, and the lens is removed along with the cataract. This discussion is a good reason why these kind of crude formulas are not used any longer, and now we use AI and computers to figure out what the correct IOL power is...

ok that makes sense.

hey ron:

so i have an expensive out of pocket appt in the am with an ophthalmologist i hope will eventually do my eyes,

beyond getting my iol master chart with all my data, is there any other info/data i should as for or questions i should ask? i already have lots of questions.

any suggestions most appreciated

A printed IOLMaster calculation sheet will have a lot of the data you need. You will want to ask what your astigmatism will be if you do not get a toric. And obviously, what the cost will be for the lens options available.