I don’t have much info. on target focal points. I assumed the monofocal that I have ZCB00 was ordered from J&J and they put in the target focal point? I was aware that often one would not get the exact target focal point but the ones that I heard about were not that far off. I know that every eye is different so it is difficult to predict exactly where it will land.
However, I had a Tecnis ZCB00 put in the LE about 5.5 weeks ago with a target focal point of -01.29 and just found out it turned out instead -01.75 which seems pretty far off. I have excellent very close in vision to about 20 inches which is ok but not what I really had wanted. The RE which was done about 5 days ago was targeted at -0.39 and now seems more like -01.00 or -01.29 from what I can guess.
Who would be responsible if the target focal point turns out to be very far off?
Unfortunately cataract surgery is not super precise and the actual result can vary by as much as half a diopter (0.5D) above or below the target. So your result is unfortunate but it is still within the margin of error. My target for my first eye last year was minus a quarter and it ended up being plus a quarter.
Probably not since I can live with what I have. It is good enough but was wondering who is really responsible for targets that are off? Could the surgeon affect this? Are the len's fp set by Johnson and Johnson? Should that be checked in the event of their possible error? These are questions I have not been able to answer due to lack of knowledge on who sets the fp and whether the surgeon has any effect on it during the surgery?
Thought mine was really off but sounds like not. I am reasonably happy with it but was surprised! Wondered who might be responsible since I didn't have any info. about who sets it? I wondered if the surgeon tweeks it in surgery?
The target is set by the surgeon based on your preference, measurements and then running it through a calculator like the Barrett calculator. That said, it is not a 100 % exact science.
the lenses typically come in 0.5D power increments and the clinic/surgeon take a bunch of measurements and use formulas to try to estimate the outcome. as others have said, it is not perfect. I also ended up a bit off target in my first eye.
Yes, I do know that as both my doctor and I set the target but then the question is does J&J or the group the monofocal is ordered from create the monofocal and send it to the surgeon with the target imprinted in the monofocal? The surgeon then does not put in the target but it is put in by the company it is ordered from? If that is the case, does the surgeon tweek it or have any effect on the outcome of what target you will actually end up with?
My targets are so off I can't believe that my doctor would not get a lot of flak from other patients if that happened often. I can live with the targets that I have as it is not affecting my vision very much and some of my vision is much better than before. I am basically pretty happy with these targets but still can't believe they are that far off??
OK in summary you are saying the lenses are pre packaged in 0.5 increments. For example, I wanted to target-0.50 for RE and my surgeon conveyed to me that it would be -0.39....was that the estimate you are talking about? So again in summary you would order from J&J a pre packaged lenses of -0.50 and would expect an outcome of -0.39? Is that how it is done?
Unfortunately, I got from about 15 inches to about 62 inches which is not -0.39 but something far different. I do notice after sleeping it is much more clear and I get a lot more inches up to 130 inches but during the course of a day it reverts to about 62 inches. I also wonder why that is the case?
J&J does not set the "target". They just supply a range of IOL powers from about 5 D to 30 D in 0.5 D steps. It is up to the surgeon to select the correct power for you based on your eye measurements and your desired outcome in diopters. You should be given a small credit card sized card that gives you the model name, serial number, and the power in diopters that was put in your eye.
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The normal practice is to do one eye, wait 6 weeks for it to heal, and then do a refraction test to determine how close the surgeon came to the target you set. Then based on the error, the surgeon should then adjust the calculation to be more accurate on the second eye.
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The first eye error was more than one would hope for but within the +/- 0.5 D standard. However, the second eye should have been closer. The surgeon should have learned something on the first eye. However, if you are only 5 days out, the refraction can still change. You will need to wait a minimum of 5 weeks and then get a refraction (eye test with an optometrist) to find out where you really ended up.
Thanks for this info. I waited 5.5 weeks for the second RE to be done and was planning on going to an Optometrist to get a reading on the LE but did not keep the appointment. The card says LE +24 and RE+23.
I am happy with the outcome but did wonder why it seemed far off from the target. One thing I have noticed is how much clearer the RE is for distance in the morning after sleeping. It gets a lot more fuzzy as the day progresses. I'll assume that is normal as I recall that from my former RE.
When everything is completed in about 6 weeks I will be posting the final outcome hoping that will give some good information to others since I have truly benefitted from this site myself! This forum provides an excellent and necessary wealth of information. Glad I stumbled across it accidentally one day! Thanks again for shedding light on this.
In reviewing this again, I am confused about one thing. Originally the target was -0.50 LE at( -039 likely outcome) I got -01.75 LE. Isn't that more than -0.5D standard?
I found this on "Review of Ophthalmology" which I thought was interesting.
“After the removal of outliers, and following lens-constant optimization, the average ophthalmologist gets about 78 percent of patients within ±0.5 D of the target refraction,” he says. “Six percent of surgeons are at 84 percent or better. Fewer than 1 percent of surgeons in that database are at 92 percent or better. Different studies around the world have found rates ranging from 55 to 80 percent. So 71 to 80 percent is sort of the acceptable range. That’s what most people achieve using the older formulas.
You said in your original post that your LE target was -1.29 D and you got -1.75 D. That is 0.46 D off the target.
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In any case have you had an optometrist eye exam done on the left eye and if so what is the written prescription for the required refraction. This is the test where the optometrist asks you which is better one or two? It should consist of a sphere diopter, plus a cylinder diopter and angle if there is any residual astigmatism. If you can provide those numbers I can try and make some sense of it.
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I assume this has not been done on the right eye as it is only 5 days post surgery and would not be meaningful. At this point the optometrist may test your right eye but will not give a written prescription as it would likely be wrong.
I can't believe myself in getting confused on the two eyes!!?? Yes, you are right LE was -01.29 and not -0.50 so, yes, indeed it fits in the -0.50 range.
The way I found out the LE was -01.75 is the day of the post op for the RE my doctor at my request sent me to technician with a machine that gave this reading. It was all very quick and he didn't guarantee it. I will go in 4.5 to 6 weeks for both eyes to an Optometrist and find out then. I will keep in mind what how you said they are supposed to test to make sure it is done right (I have had that type of test before so know what you are talking about).
In reading more about the way Ophthalmologists do the calculations for the target FP I have become aware that there are more advanced ways of doing it which can guarantee better outcomes. I find it hard to believe my young, modern thinking doctor would use an old method so I don't know how she got this result which was far off of target?
Oh, well more mysteries that are unsolved rendering one forever questioning! Thanks again for your help on this!
Did you have an ORA scan done at the time of surgery? If so, then the surgeon will choose the target from that, and decide if there is any astigmatism present (and then possibly choose a Toric lens instead). How and where the lens is placed will affect the results also. You could ask the surgeon what they hit with the RE eye like I did -- the info should be on the computer (at least that's where my surgeon checked). Ask also for a copy of the pre-scan results and post them here -- Ron can analyze them for you, lol. It looks like your surgeon hits their targets on the more myopic side. If so, I would have thought that they would have suggested a different target for the second eye, maybe -0.25D. Although I know that you were concerned about too much of a difference between both eyes, so maybe they stayed with the original target because of that. How are both eyes working together?
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"One thing I have noticed is how much clearer the RE is for distance in the morning after sleeping. It gets a lot more fuzzy as the day progresses."
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The eye is still healing, so as others have said, I'd give it more time, and from my own experience use preservative free lubricating drops regularly for at least the next month or so, with the prescription drops if you're still using those -- just time putting them in at least twenty minutes apart. They will reduce friction and scratchiness in the eye and promote healing. I also found that my eyes got tired more quickly post surgery so I made a point of not spending as much time on the computer in particular. I know they tell you that it's okay to use one, but they don't really specify for how long, and since people's eyes get strained from it to begin with, I thought I'd regiment my usage for the month post surgery.
Both eyes seem to be working well together and overall I am not unhappy with my new eyesight. I have gotten some good things like excellent close in vision for those trips to the book store when I previously could not read through the books since I never had glasses with me or used them!!I And the RE distance that I now have although not what I had wanted at least allows me to see the pavement when I walk. I had tripped and gashed my head severely about a year ago since the pavement was so vague with my old cataract laden eyesight!
I did a scan which is probably the ORA scan in early February. They said the results lasted for 6 months so my surgeries fell within that time frame. Maybe i will check into it more and post something for analysis.
Your eye could still change in the next month or two while healing continues.
I'd suggest going to an optometrist about 3 months after the cataract surgery to get a precise Rx for comparison.
The auto-refractor used may give a reading off by 0.25-0.50D too.
Get a full refraction after the full healing period and after you have stopped using the Rx eyedrops, I found they affected my vision until I could stop using them a few months after surgery.
But as has been noted, an error up to 0.50D in either direction is possible with cataract surgery using standard IOLs. Thats one of the reasons the new type of IOL that is adjustable after surgery with UV light are becoming popular since they can be adjusted after eye healing to get an exact result unlike conventional IOL cataract surgery. Only option to adjust the eye Rx for conventional IOLs is with Lasik.
My refraction changed after 6 months
The ORA would have been done during surgery when they opened the eye and removed the old lens -- I guess you could request a copy of that if you had it done, I didn't think of it at the time for myself. I was referring to the results from a Lenstar or a IOLMaster scan. Those are most likely what was used in your pre-op scan. Just call the office and ask them to either print a copy out for you, or email it. It took them fifteen minutes when I asked for a copy of mine when I went in for the second day checkup of the second eye.
Interesting about the new IOL. I am sure that will be a hit.
Yes, I will be going 4 to 6 wks to the Optometrist for another reading.
Interesting info. about the auto refractor being off possible which the nurse had mentioned to me also.
I didn't know the drops affected eyes after stopping usage. I can't tell now if the steroid drops are affecting my vision. Seems the same.
Overall happy with results I have gotten as I walked around for years with weaker eyes never wearing glasses. I can adjust to anything it seems!!