Recommendation for upcoming cataract surgery
Posted , 7 users are following.
Hi All
I am 45 year old and I am scheduled to go for cataract surgery in January 2024 in my left eye and I have some anxiety related to it. My doctor has suggested J&J AR40E (J&J Sensar Monofocal 3-Piece) lens aiming for distance vision (with emmetropia as final refraction). Although he is also fine with aiming for near vision but leaves the choice to me. However, I feel I dont have all the understanding to make an optimal decision.
I am listing below my situation and preferences and will appreciate it if you can recommend, based on your experience, what can be a good approach for me. Also, please share any epxerience/opinion with J&J Sensar Monofocal 3-Piece lenses.
- I am highly myopic (around -15D in both eyes) and have been wearing thick glasses pretty much my whole life.
- My current visual acuity is .3 in the eye that is going to be operated and .5 in other eye.
- My work involves heavy computer work and reading.
- I currently have lot of issues with night vision; halos, glares, difficulty in dim/low light conditions. This makes it difficult for me to do things like driving car at night, being in low dim places like restaurants etc. My preference will be to get rid of these issues and I dont so much care about whether I have to wear glasses (either for slight myopia or reading glasses) after cataract surgery.
0 likes, 60 replies
trilemma sozkumar
Edited
Let me take the easy one. I think he is aiming for making your best focus to be about 2.13 meters (7 ft), which would be trying to give you good distance vision. He will not be able to get that precisely. It is a target. If he gets close, that will be wonderful.
sozkumar trilemma
Posted
Hi Trilemma
Can you please explain how you obtained 2.13 mts.
RonAKA trilemma
Edited
My guess was that the IOL power to be used is -2.5 D which is very low, but in the range needed for very highly myopic eyes. And the expect outcome is -0.47 D which means about -0.50 D myopic instead of -15.0 D as the eyes are now. This is basically distance.
trilemma sozkumar
Edited
The diopter (D) is a measure of focus, but it is the reciprocal of meters.
1 / 0.47 = 2.13
What is nice about diopters is they add. If you put a 0.5 D lens in series with a 2.0 D lens, in effect you have a 2.5 D lens.
If you put a +0.5 D lens in series with a -2.0 D lens, in effect you have a -1.5 D lens.
Dapperdan7 RonAKA
Posted
rom, is there a way to calculate how lens power equates to refreaction? is it different depending on each eyes unique features (axial length, anterior chamber depth, astigmatism, spherical abberation?
the -2.5 lens equates to around -.47 refraction. how is this done?
thank you
Guest Dapperdan7
Posted
It's done with the IOL Master (or similar) and whatever formulas you tell it up to use (Barett, etc). The main factor is axial length and yes each eye can be slightly different.
RonAKA Dapperdan7
Posted
It is as @david98963 explained. In the 1970's before the sophisticated instruments to measure the eye and modern computerized calculation formulas the old formula was:
18 + (Sphere refraction x 1.25)
So for a -15 D refraction that works out to be:
18 + (-15 x 1.25) = -0.75 D
However that is very crude and just puts you in the ballpark...
RonAKA sozkumar
Edited
Some further thoughts about your situation.
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On the targeting accuracy consider that for good distance vision without glasses you have to hit the window between -0.50 D and 0.00 D. That is a pretty small target, considering your extreme myopia. If you are targeting distance in both eyes you get two shots at it if you consider both eyes. However, the first shot will be the least accurate. It is kind of the same deal with targeting mini-monovision. You have one shot at the distance eye and one for the near eye. But, you need to be close on both of them. That is why choosing near vision is an easier target. As long as you get in the range of -2.0 to -3.0 D with the first eye and refine that hopefully to -2.50 D with the second eye, you should get good near vision without glasses.
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While I am not a big fan of doing lens replacement in an eye that has no cataract, your case may be one where it could be considered, especially if you have any signs of a cataract developing in the other eye. If you do both that addresses the big differential you will have between the eyes when just one is done.
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And due to your younger age, being male, and very myopic, you are at elevated risk of retina detachment as a result of the cataract surgery. Risk is still low, but the potential is there. Be sure to discuss that risk with your surgeon, and possibly consult with a retina specialist as well. There is not much you can do about it to lower risk, but you can be fully prepared for it by knowing what the signs are, and having a plan to get the eye looked at on an emergency basis if symptoms occur. Immediate treatment is required to prevent the damage from becoming permanent.
Dapperdan7 RonAKA
Posted
choosing near vision as an "easier target" is because he is already very myopic?
RonAKA Dapperdan7
Edited
No, it is an easier target because it is larger. Near vision between -2.0 and -3.0 gives a full 1.0 diopter target to hit. And it can be refined with the second eye after seeing where the first eye turns out. A target for distance vision is -0.50 to 0.00 D. That is half the size of the near target.
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I know some surgeons recommend near for pre-surgery myopic patients. I think that is a bit of a cop out. They give patients what they are used to, and overlook targets that may be better. I think their main objective is to minimize complaints and chair time instead of looking for opportunities to improve the vision of patients.
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I prefer mini-monovision but when you are starting at -15.0 D and need to get both eyes very close, that seems risky and I have a hard time recommending it in this case.
sozkumar RonAKA
Posted
Hi Ron
Thanks again for detailed replies.
I am now inclining towards going for near vision but I will have more consultations before the final decision.
I will get the study you have mentioned and read/discuss it with my doctor. It will give a good basis for discussion about the formula used and the choice of lens.
With respect to risk of retina detachment, I have had it in this same eye about 5 years ago and it was treated with Vitrectomy and silicon oil. The doctors are aware of this. So you are right about the risks related to retina detachment, but there is not much that can be done about it,
RonAKA sozkumar
Posted
It is not unusual to run your numbers through two or three different formulas that are appropriate for your very long eyes. The hope is that they all give the same answer and then you have high confidence that the right power is being selected. But, you also have to be prepared for them giving different answers on the correct power. Then a judgement call is needed, and you would be wise to depend on the judgement of a surgeon experienced in working with long eyes, to make the final selection.
Dapperdan7 RonAKA
Posted
so a longer eye makes for more difficult results?
RonAKA Dapperdan7
Posted
Yes, for sure, especially when you get into eye lengths greater than 30 mm.
RonAKA sozkumar
Edited
On a quick look I found this more recent article (Oct 1, 2023) which compared the modern formulas for accuracy with long (> 30mm) eyes. They further divide it into group 1 (30 < axial length ≤ 32 mm), and group 2 (32 < axial length ≤ 35 mm). Unfortunately you appear to be right in the middle of these two with an AL of 32. Splitting hairs it technically fits into group 1 as that includes 32 mm. It would probably be worth while to get the exact AL and each eye may fit into different groups.
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In any case from what I can see the top two formulas for group 1 are the Hill-RBF 3.0 and EVO 2.0. In group 2 the top two are the EVO 2.0 and Cooke K6. Since 32 mm is in the middle one would have to pay particular attention to the EVO 2.0 predictions. It is available on line.
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The other complication is that they make mention of a meniscus type lens needing something different again. The Sensar AR40M from the information I see is a meniscus lens and covers the range of -10.0 to +1.0 D, and may be the type needed for this eye. But, to make things even more complicated If one uses a target of -2.5 D then the power required may shift out of this range to the AR40E which is a bioconvex lens instead of a meniscus. If the meniscus lens is required then the best formula points to the Cooke K6. Very complicated!! One needs to proceed with care...
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In any case here is the name of the study which seems to only be available on line as an abstract. The full article in electronic form is listed at $40. It may be well worth buying it to see all the details.
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Accuracy of Seven Modern Online IOL Formulas in Eyes With Axial Lengths Longer Than 30 mm
Er Mo, MD, Zexin Chen, MD, Ke Feng, MD, Fuman Yang, MD, Jin Li, MD, PhD, and Yun-e Zhao, MD
Journal of Refractive Surgery, 2023;39(10):705–710
Published Online:October 01, 2023