How close can I see with Alcon Clareon monofocals set to distance?

my surgeon said will target for -0.2D for distance. Is that good? how precise is this target? i don't want to end up hyperopic!

i do have -0.75 astigmatism which the surgeon said i dont need a toric IOL. hiw do i know my astigmatism is against the rule? what does it mean by "against the rule"? why would having some astigmatism help with improving closer range of vision?

thanks!

Yes, in nominal terms -0.25 D is a good target for distance vision with an IOL. However, that said, there is no way for an ophthalmologist to dial in a -0.25 D outcome. The IOL powers come in 0.5 D steps and what they actually do is set a nominal target, and then see what the available IOL powers in that range will actually produce based on the IOL calculation formula. So what they will see is a column of power choices with a predicted outcome for each. If the nominal target is -0.25 D then there will likely be one power that will be above that, and one power below. They ideally with your input will have to decide to go with the one higher or lower. Or you could win the lottery and one power will be exactly -0.25 D. So, perhaps what your surgeon is saying is that their prediction for a certain power that they are planning to use is -0.20 D. That is very close to the nominal -0.25 D, and that is a good choice.

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Normally when the predicted astigmatism is less than -0.75 D then a toric is not warranted. When the astigmatism is in optometrist format with negative cylinder my understanding is that against the rule is when the axis is around 90 degrees. With the rule is around 0 deg or 180 deg. With the rule is more common in younger people, and against the rule more common in the elderly.

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Think about sphere being the basic power with -1.50 giving good near vision. When you have -0.75 D cylinder (astigmatism) part of the eye is actually at -2.25 D (the sum of the two. That gives you nearer vision, but also with less visual acuity.

hi Ron,

so the target my surgeon will dial in -0.20 D can be used for a high myope? i am highly myopic with L eye -11.5 and R eye -10.5. if he chooses the one power above -0.20D, that means i will have a bit more than -0.20D myopic (maybe -0.3 or higher)?

does against the rule or with the rule astigmatism affect cataract surgery outcome?

if after surgery, my residue myopia is -0.50 D , with a -0.75 astigmatism, is it like a power of myopia of -1.25 D so I might see intermediate better?

Yes, that target is still ok with high myopia. Your myopia is quite high, and that would require a fairly low power IOL. A rough rule of thumb calculation would be in the range of a +4.0 D lens. That may be a problem as at least early on, the lowest power the Clareon was initially available in, was +6.0 D. However, if your surgeon has already measured your eyes and is recommending it, then there must be a suitable power available. It would be worth asking what power of lenses are available. Sometimes when you get to the extremes of the lens power range the steps between sizes increases from 0.5 D to 1.0 D. That would make smaller adjustments more difficult.

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When you choose a higher power than what is needed for plano vision then you leave some more of the myopia. And if -0.20 D is possible, and you choose an IOL with 0.5 D higher power that will bring the residual to about -0.50 D, which if you are really afraid of going positive or far sighted, it is an option. It puts 20/20 distance vision at risk though.

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There are some IOL Calculation formulas that are more suitable for high myopes, and I would hope the surgeon would use them. Another option to consider is using a surgeon that has the Alcon ORA intraoperative aberrometer system. They measure your eye again during the cataract surgery, after your natural lens is removed, but before the IOL is inserted. They make the final lens power choice at that time. I believe it is fairly expensive add on option, but may make sense in your case if your objective is to be eyeglasses free after surgery. If that is not a priority, and you are willing to wear glasses then a more accurate correction is not essential. One contributor here was highly myopic and had the ORA system and got a very accurate outcome. Another I recall used it and there was a miss. So YMMV. It may be worth discussing with the surgeon if they offer it.

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With or against the rule astigmatism does not really affect the outcome. Some surgeons choose the incision location to minimize the surgery induced astigmatism, and it may be a minor consideration. But, beyond that there is not much they can do differently.

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IOL Power calculation predictions are done on a spherical equivalent basis. That is (when astigmatism is reported as negative) the sphere plus 50% of the astigmatism. So, in your example of -0.5 D sphere and -0.75 D cylinder that works out to be -0.875 D, or about -0.9 D. Nearer vision will be better due to the more myopic spherical equivalent, but perhaps not as sharp. My distance eye was targeted to be about -0.3 D SE, and ended up at 0.0 D sphere, and -0.50 D cylinder for a SE of -0.25 D, pretty much right on target. However, on my last vision check my astigmatism had increased to -0.75 D with sphere remaining at 0.0 D. So I am no at about -0.375. My near vision is pretty good. I can see very well down to 2 feet and with a computer monitor I can still read normal size text at 18". But, individuals vary on what they get with near vision. A more typical expectation would be 2-3 feet.

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Hope that helps some

ORA is not an option for my surgeon. unfortunate! but my cataract is a 2+ and they said its mild, so i am guessing they can get my eye length measurement quite accurately?

i thought the power of the IOL should have similar number as my myopic rx but with the opoosite sign? for example, my L eye is -11.5 so i would need a + 11.5 IOL?

how accurate is the formular to calculate the correct IOL power? according to my surgeon, he said quite precise. But i will have a pre-op with him to finalize the details of the IOL and power in Dec.

Ron, since you have arysoft in one eye and clareon in the other, are they any different? how much do you know about dysphotosia from these IOL? i heard minimal people still complain about positive dysphotosia with monofocals, so i am worried even choosing monofocals, dysphotosia still happens!

The old formula that I used to make the rule of thumb estimate is to take your pre-cataract eye prescription for sphere multiplied by 1.25 and then add it, respecting signs to +18 D to get your IOL power. So for a -11.0 D prescription for sphere the calculation would be as follows. The cataract may have changed your prescription, so you could possibly get some better accuracy if you can find what your eyeglass prescriptions were a year or so before cataracts started to appear.

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(-11.0 * 1.25) + 18.0 = +4.25

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Keep in mind this is a very crude formula used in the 1970's before today's advanced measurement instruments and computerized formulas. There can be a lot of error in this old rule of thumb formula, and it would never be used today. Google this for some information on it:

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Dr. Hill IOL Power Calculation formulas

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Dr. Hill is the originator of the Hill-RBF 3.0 formula which is based on AI and is considered one of the best. You should ask your surgeon to show you the predictions for your power need based on this Hill formula and the Barrett Universal II. They are two of the best for high myopes (long eyes). The Hill formula will issue warnings if it considers your power is out of the range that it is accurate in.

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This said if the rule of thumb is in the ballpark you may have issues getting a Clareon lens that low in power. Alcon makes some AcrySof lenses however that actually go into the minus power range, but they come in 1.0 D steps instead of 0.5 D steps. AcrySof is optically identical to the Clareon lenses.

The prime difference between the Clareon and AcrySof IQ is the new material used in the Clareon that is claimed to be much more resistant to the formation of glistenings. It also is said to have a higher light transmittance - possibly the source of the Clareon name. It also has sharper edges which is supposed to make it more resistant to PCO.

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My experience is that I essentially see no difference in clarity or optical side effects like dysphotopsia. With very specific conditions of near total darkness and a point light source off to the side, I do see some arc shaped flashes in my peripheral vision with both lenses. I suspect it is reflections off the edge of the lenses when my pupils are wide open. That said it is more of a curiosity than a problem. I almost never see them, but they do happen.

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Interestingly with respect to PCO my optometrist is now telling me that he sees some in the Clareon eye (which is supposed to be more resistant to it) which has been in for about 18 months now. I don't see it though. He says he sees nothing in the AcrySof eye which has been in for about 3 years. He is suggesting I consider YAG in the Clareon eye. Will be getting a second opinion on it later this month.

With monofocals, dysphotopsia is much less likely. But yes, it can happen. Still, if you have cataracts, they will certainly become more dense over time, making eye measurements and even the surgery itself more difficult.

I can actually read J1 with my Eyhance set for distance (i.e. small print at 14"… a very unusual result)

That very unusual . My Ehyance set at distance struggle with J8.

Yes I was shocked too. I got very lucky I guess. I do have -0.75D of astigmatism helping me out. And again it requires very good lighting (like direct sun is best). But I can read it. Can read my Phone / iPad as well starting at about 10-12" away. Bit that is very atypical. The final refraction for that eye was +0.25 Sphere, -0.75 Cylinder @ 168° Axis.

your final refraction of +0.25 means you became hyperopia? were you far-sighted before surgery? i heard if you were short-sighted and became hyperopia, it can be extremely uncomfortable even though i dont know what the uncomfortable means!

We use Barrett Universal II which outputs predictions as spherical equivalents. The target was -0.21. And so on a spherical equivalent basis we actually came close to nailing it as the SE is slightly near sighted. I was -4D uncorrected before surgery (near sighted / myope)

hi David, your final refraction is -0.2 or +0.2? if it is +0.2, i heard that will be unconfortable for myopic patients to become hyperopia. how do you feel and see?

My target prediction was -0.21 spherical equivalent. My final refraction was +0.25 Sphere -0.75 Cylinder which is -0.125 spherical equivalent. So on a spherical equivalent basis I am not hyperopic and we essentially nailed the target.

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I can read J1 in very bright light (like full sun) and read my iPhone 12 Mini, iPad, and 44mm Apple Watch good light (daytime or overcast but still bright). It's okay but not not razor sharp but that is still much better than what most monofocal recipients achieve. Near vision drops off very fast in low light, as expected.

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Distance vision is good but I'm not happy with the Astigmatism. It is most noticeable with thin high contrast subjects like power lines or twigs in trees… they can exhibit a slight "smudge" or ghosting effect. But with glasses to clean up the Astigmatism the distance vision is razor sharp. I had -0.50 Astigmatism before surgery too though, I just never noticed it because my Sphere was -4 and I always wore glasses.

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I also developed Starburts 6 months AFTER surgery and I have PCO that started within a month of surgery so that is likely what is causing that, not the lens. If it gets bad enough I may have to consider YAG which would hopefully resolve that issue. I'm worried about YAG. The can opener pattern risks a big floater from the capsular flap and the cruciate pattern risks pitting which could cause even worse starbursts.

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So it's a mixed bag. Overall though I guess I did pretty well. The near vision in particular is beyond my expectations (in good light and especially in bright sun… in bright sun it's incredible). Distance is very good without glasses and spectacular with glasses (to clean up the Astigmatism). The Astigmatism and Starburts are a bit of a drag though. And it is disappointing how I lose my near vision in low light but again that is 100% expected with ALL lenses given today's technology.

david, do you have Alcon Clareon as well?

Eyhance

@henry35359, @david98963 did your surgeon use laser or traditional for eyhance? i was told by my surgeon he only uses laser with eyhance to treat my astigmatism at the same time but i wonder if LRI or toric can be used instead. did you have astigmatism? thanks.

Your surgeon may be using laser to do the LRI.