Measure twice (or more), cut once?
Posted , 7 users are following.
As I wrote in another post, I ended up with an expensive multifocal (Acuity) giving me intermediate vision (and not that clear yet—but it's been only 9 days). I wanted very clear long-distance, OK intermediate, and I was fine to needing glasses for reading. Now long-distance is
Since the lens seems to be placed properly and there are no other problems, I believe that this undesirable (to me) result is due to miscalculation in choosing the lens.
Frankly, I am suprised that they only took on set of measurements because even woodworkers know how important it is to measure twice and cut once. And if that applies to a $3 piece of 2x4, one would expect a series of measurements averaged over, say, a couple of days—because, I assume the eye changes a bit throughout the day.
Before I end up with another lens miscalculation, I am thinking of getting a second opinion or measurement of my eyes. Probably with another optometrist/dr.
Does this make sense? Have any of you done that?
Thank you!
1 like, 25 replies
RonAKA RandallG
Posted
I have not heard of an IOL with the name of Acuity. Are you sure that is the brand name? They should have given you a card at the time of your surgery that gives the brand name, model number, and serial number of the lens.
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The first thing I would suggest is waiting 6 weeks and then getting an accurate measurement of where you ended up with the lens. The best way to do that is to see an optometrist and get an eyeglass prescription for the eye. That will tell you where the sphere ended up along with the amount of cylinder (astigmatism). Once you have that information then you can made a better decision about what to do with the second eye.
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I ended up having at least two measurements of my eye, but I think that was a result of the long wait time from the first consult to when the surgery was going to be done. On the astigmatism amount the surgeon used two different methods to predict what I would get. One thing to keep in mind is that unlike eyeglasses you typically (hopefully) only get an IOL once over your lifetime. And, fortunately the eye tends to remain quite stable and does not change that much if at all over time.
RandallG RonAKA
Posted
Thank you Ron, sorry, I meant Vivity, not Acuity. I will correct that.
Waiting the full six weeks sounds sensible—although I am not expecting (hoping for) that dramatic a change.
I got none of that. I will ask the next time I see the dr.
Thank you!
RonAKA RandallG
Posted
You are advised to keep that card in your medical records in the unlikely event that there is a recall of the lens. Then you can confirm if your lens is affected or not.
RonAKA RandallG
Edited
I had forgotten your other post. I believe you have a Vivity lens by Alcon based on it....
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There are different methods/instruments used for measurement. I think the best one is the IOLMaster 700, and I would seek out a surgeon that uses that instrument. And for most eyes there are a couple of formulas that can be used for the best accuracy. One is based on artificial intelligence and is called the Hill RBF 3.0, and the other the Barrett Universal II. It is best if they run both of those formulas using the IOLMaster 700 measurements to see if they agree. If they agree then the outcome should be good. But, there can always be "surprises"....
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The other credible instrument is the Haag-Streit Lenstar LS900, but it seems to be a little less popular than the IOLMaster.
RandallG RonAKA
Posted
Wow, you know your optical instruments Ron!
I believe in being an informed patient. I am not sure that the office/surgeon like that. However, given the very disappointing results from the first operation, I will seek to be more informed and ask for multiple tests/opinions before committing to a surgeon or specific lens.
PS I am surprised that they actually need AI to determine the best lens!! I thought that it was a relatively straightforward optical calculation.
I wish I had found this forum BEFORE my surgery and decision, but I am thrilled to have found it now—especially with such knowledgeable and helpful people as you, Ron.
Thank you!
RonAKA RandallG
Edited
Actually the process of taking measurements and determining the correct power of IOL is quite complicated. It depends to some degree on whether you are short sighted or far sighted and by how much. The main measurement is the length of the eye. Some older formulas require adjustment based on the length of the eye. The newer ones do not. If you google this you should find some information and a table comparing the different formulas. This site is by Dr. Hill who runs a clinic in Arizona and is behind the Hill RBF method. It may talk about RBF 2.0, but that has been replaced with the RBF 3.0. I presume they have updated it with more data from the AI process. Look for a tab/link called Calculation Formulas. I believe Dr. Hill favours the Lenstar instrument, but says his formula works well with the IOLMaster as well.
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doctor hill iol calculation formulas
Guest RandallG
Edited
I've also heard that having a healthy tear film is important for getting good readings. And most older people nave some degree of dry eye. I've heard of some ophthalmologists that recommend using eye drops like Systain Complete (for example) for a month before the measurements. I'd say the overwhelming majority of surgeons do NOT do this though so maybe it's not that important. But it does seem to make sense.
RandallG Guest
Posted
Thank you, David.
I followed my dr's orders to use dry eye drops the day before and the day of the exam. Although I did not use the Systain drops at the time but TheraTears. I am using the Systain ultra now.
I appreciate you taking the time to answer!
greg59 Guest
Edited
Yes, one of the surgeon's that I talked has published research on the importance of tear film on biometry and he wanted me to use preservative-free drops like Sustane Complete (Alcon) at least three or four times per day. Also wanted me to redo the biometry after one failed attempt to get good readings without the drops. I took his advice and ended up with reasonably good biometry and hit my targets fairly well in both eyes.
Bausch&Lomb has BioTrue (Glycerin) PF that is a simple solution and seems to work as well for me as Sustane.
RonAKA greg59
Posted
My wife likes HYLO eye drops, but I find it ridiculously expensive for what you get. I don't use drops very often any more since I stopped using contacts after my second cataract surgery. But, when I do put them in occasionally I prefer the HydraSense Advanced for Dry Eyes from Bayer. It contains 0.15% Sodium Hyaluronate (50% more than HYLO), which I believe is the most effective ingredient in these drops. HYLO on the other hand contains 0.1% Sodium Hyaluronate. At Costco HYLO costs about $38 for 10 ml, compared to HydraSense at about $8 for 10 ml.
RandallG RonAKA
Posted
Thank you, Ron. I'll add that to my Costco shopping list.
RonAKA RandallG
Posted
It is available in Canada, but not sure about the US. It may be possible that hyaluronate is not available OTC in the US? Or, Bayer markets it under a different name. In Canada it is hard to miss as they have constant adverts on TV for HydraSense.
billy111 Guest
Posted
David,
What you said about healthy tear film is spot on. Dry Eye Disease can affect cataract measurements and even the recovery from surgery. It is recommended to instil artificial tears right before you have measurements done.
Sue.An2 RandallG
Edited
Just to add to everyone else's comments. Were you wearing contacts prior yo surgery? normally they should be removed for 2 weeks prior to the eye being measured.
Also if you had prior lasik or PRK surgery for improving distance note that too makes it more difficult to get an accurate measurement - helps if one has those pre-lasik measurements.
Then there is the fact IOLs come only in .50 increments (unlike glasses in .25) . Healing processes can shift the iol a bit adding to a variance from target.
This is so much better than our grandparents surgery and will get better in time. Maybe there will be a non surgical procedure developed too.
But this is main reason most of us are not for having cataract surgery on both eyes same time. Time allows for adjustments to 2nd eye.
RandallG Sue.An2
Posted
Thank you, Sue.
No I did not wear contacts before. Nor did I have lasik.
I was farsighted from ~40 to 58 yo, then developed a myopic shift and became nearsighted in both eyes from 58 until now, 62 yo.
For sure. We should be grateful!
Agreed. I cancelled my 2nd surgery that was scheduled just 2 weeks after the first.
Seeing my eye dr. on Monday—that would have been 2 weeks since the operation. Let's see what happens.
Thank you for your help and advice!
RonAKA RandallG
Posted
I think the big issue with contacts are the hard ones. They do change the shape of your eye and it takes some time for the eye to go back to the natural shape. Hard contacts are not that popular any more, as most use the soft ones. It is not clear that it is necessary to go without soft contacts for a week before measurements. But, I was aware of the issue and stopped wearing them a week before, even though the surgeon did not warn me.
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Google cause of IOL Refractive Surprise to find articles on the issue. Here is a quote from one article.
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"Main sources of postoperative refractive surprise are errors in biometry, such as, inaccurate preoperative measurements (axial length [AL] or keratometry), IOL calculation formula, IOL insertion, and lens constant’s errors [1]. Other common reasons for ‘wrong’ IOL implantation as reported by Steeples in their study of 178 cases are: inaccurate biometry, wrong IOL selection, transcription errors, handwriting misinterpretations, change in list order, right/left eye confusion, patient identification issues, misfiled biometry, wrong IOL written on theater white board, optimal IOL power unavailable in stock, wrong IOL power implantation after complicated surgery, wrong patient notes, communication errors, or - as in the case presented herein - an IOL mislabeled by the manufacturer [2]."
RandallG RonAKA
Posted
Thank you, Ron.
So many different potential causes of error ... scary!
RonAKA RandallG
Posted
One thing you can do on your second eye is to ask for a copy of the IOL Calculation sheet. I believe both in the US and Canada there have been court decisions which have determined that medical test results are the property of the patient and you have a right to see it. It is really only the click of the mouse for them to get a copy for you. Then you can take the measurement data and use a few different on line power calculation formulas to "check the work" of your surgeon. I was much less aware than I am now of this kind of detail, and never asked for it when my measurements were taken. My brother is now about to get surgery and I have been helping him. He got a copy of his measurements and I have run the calculations. My thoughts are that the surgeon is off by 0.5 D in his IOL power selection. So then what do you do? Tell the surgeon he is off? Or, just accept they are the expert with experience doing thousands of eyes and go with the flow? So, it opens a can of worms that you may not want to deal with....
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If you google Zeiss IOLMaster 700 Quick Guide Printing Functions EN PDF you should find a document that shows what the data sheet looks like and explains what it is all about.
RandallG RonAKA
Posted
Thank you, Ron.
You are right about the can of worms.
I need to get both the information about the IOL that they implanted (the card with the specs and the serial number) and all the measurements that they took.
Of course, my surgeon is not going to take kindly to that.
A real dilemma and a tough spot.
Sue.An2 RandallG
Posted
Randall your surgeon should be willing to have a dialogue. If the mere question sets him off maybe get another opinion from another surgeon (might even be worth it anyways.
RandallG Sue.An2
Posted
Thank you, Sue.An,
I definitely plan to get a second (perhaps even a third) opinion and measurements and lens choice before my next surgery.