I have two surgeons giving me very different targets for my L eye cataract surgery monofocals IOL. I like to set to see distance clear, and i am high myopic -11.5 in L eye while -10.5 in the other, what is a reasonable target that surgeons usually use ? one surgeon suggested -0.2, the second surgeon targets -1.0. Why a big difference? how accurate will these targets be after surgery (plus or minus 0.5 or more)?
i am at a lost here because i don’t know which surgeon to trust since the targets are so different. The last thing i want is blurry at all distance with a monofocals!
thanks for any help you can provide.
Yes the results can vary by as much as 0.5D over OR under the target. It usually isn't off by that much but it can be. The best target for good sharp distance is the -0.2 target. Predicted outcomes are usually in 0.34D steps so the next step down in power would be +0.14 which you do not want… you'd be far sighted for sure which results in poor vision at all distances. The next step up in power would be -0.44 which will almost certainly not result in 20/20 distance. Ypu would be slightly near sighted. So -0.20 is the way to go.
high myopes do well with residual myopia. j personally chose -0.45 even with trifocals and i am happy with the distance vision. i wear glasses for -0.75 astigmatism so i get the myopia correction with it for one eye.
because of the residual astigmatism, even if i were to go with a mini monovision i would target the plano (distance) eye to between -0.5 and -0.75.
also it is better to err on the myopic side as it is easier to fix with lasik.
you might do even better with more residual myopia given your high myopia.
good luck!!
the 0.34D is what the instrument will calculate in increment?
i am afraid if the -0.2 target is missed, i might end up hyperopia. is this target usually set for everyone doesnt matter high myopic or not?
i just got a message back from my surgeon that he plans to use a 8 diopters Alcon clareon on my L eye, the predicted outcome is -0.3. but he also said the calculation is not as precise!! that's very confusing to me!
did you have both eyes set to -0.45 as your target and you hit the target? what were your glasses prescriptions before surgery?
i dont know how good and accurate the calculation is but the surgeon who target -0.2 said its not precise but yet instead of -0.5 to -0.75, he target -0.2?? that doesnt make sense to me!
i have had 3 surgeries. for the iols in my eyes they were set for -0.4 and -0.45. the -0.45 ended up plano and -0.4 ended up -0.25.
on a previous surgery the iol chosen was for -0.37 myopia. ORA confirmed it during surgery at -0.19. ended up -0.25.
if he said we will choose -0.2 the your measurements with that iol are -0.2, -0.55, -0.9. increments of 0.35D. in such a scenario i would choose -0.55.
if he says outcome is -0.3. then your measurements are -0.3, -0.65, -1. you should be OK with -0.3. i would choose -0.65 because of the same fear as you. residual myopia is easier to fix with lasik. with high myopia -0.65 is going to be negligible for you.
clareon is a very good lens. as a high myope i would be tempted to use clareon vivity with -0.65 in the first eye. then play with contact lens and get more myopia with the vivity in the other eye for better near.
you should also research mono vision which works for many. ronaka has a combination like that. these options can help with glasses independence.
IOLs come in 0.5D steps which translates to about 0.34D in the eye. So people talk about targetting but the measurements and formulas tell you what the predicted outcomes are. If you want to "target" -0.50 you'd choose the IOL power that coincides with the -0.54 predicted outcome. If you want to target plano you'd choose the IOL power that coincides with the -0.20 predicted outcome. The +0.14 is closer to zero (plano) but they never choose a far sighted prediction.
did you have an IOL exchange?
whats the brand IOL do you have now that shifted from -0.45 to 0? monofocals?
my cornea surgeon who suggested -1 as target said the monofocals he will use is B&L Envista. He said my astignatism mostly from the lens as my cornea shape is almost perfect (i dont know if i have any corneal astigmatism but currently L eye glasses has -0.75 astigmatism corrected). However i havent had my measurements yet.
You have mentioned ORA usage in your first surgery. is it better to use ORA to measure during surgery for high myope like me so there wont be any hyperopic surprise?
yes. i had an iol exchange in left eye for lens edge glare.
i have clareon panoptix now.
astigmatism is unpredictable. mine is surgery induced.
ORA has divided opinions. it was accurate for me. for the second surgery the surgeon said he doesnt use it anymore as it has hurt him in the past.
get reading from multiple doctors. these are iol master readings. then they use different formulas for coming up with the iol power. compare them. i did it with 4 for first surgery. the calculations for the too surgeon in my city were way off. he would have left me hyperopic by 0.75.
as a high myope at least get a reading from a top surgeon. so that the right correction is applied
can you explain this line you wrote please? im confused..
"IOLs come in 0.5D steps which translates to about 0.34D in the eye. "
thank you
IOLs are made in 0.5D steps but that doesn't translate to 0.5D steps in the eye, it translates to approximately 0.34D steps in the eye. So if a 17.0D power IOL has a predicted result of 0 Sphere when implanted, then the 17.5D power of the same IOL will have a predicted result of -0.34 not -0.5. That's just how it works. It's because of where the IOL sits along the visual axis. It's the same reason that an eyeglass prescription isn't exactly the same as a contact lens prescription, because glasses sit on a different visual plane (further away from the eye).
this is correct information. 0.5D change in IOL power translates to 0.35D refractive change for me.
Yah maybe it varies ever so slightly from IOL to IOL. The 0.34 refractive steps I saw were from my calculation sheet for Eyhance.
is there a time frame for lens exchange?
do you know how the prescription on IOL is set? for example, lower number e.g 8D IOL is for high myope but 30D IOL is for non myope? the smaller the number on IOL, the higher the patients glasses presciption in the myopic side?
i would recommend do it right the first time. if doing an exchange go to an expert regardless of timeline. 3-6 months is preferrable. i did it at 5 years.
19D is about plano. lower than that for myopes and higher than that for hyperopes. i am 16 and 16.5.
For more info about a lens exchange, Google " Healio IOL exchange all about patient expectation"
It's a discussion with several cataract surgeons, written Dec. 2021
When targeting for distance it is normal to target -0.25 D. While 0.00 D would give the best vision there is always a margin of error in your actual outcome. It is better to be -0.50 D than to be +0.50 D. Both outcomes would give about the same distance vision, but the -0.50 D will give better near vision. That is why the target on the slight myopia side.
For high myopia it is good to get surgery on your worse eye first and target a bit of residual myopia, e.g. -1D to -2D. Then after you see the result (10 days post-op) you can use that result to help you target the second eye a little more for distance, if that's what you desire.
really you need to decide what would be an ideal outcome for you and your lifestyle, and whether you want your unaided vision to be best for reading, intermediate or distance. If you target -0.2D, there is a good chance you may end up with some hyperopia. Most likely you'll land within 0.5D of your target, so +0.3D to -0.7D, but it's not unusual to land up to 1D off. Personally I would be very unhappy to end up hyperopic and would target -1D.
If you choose a monofocal plus like the Tecnis Eyehance then you get a broader landing zone, and may have a better chance of getting 20/20.
I personally would like the crisper clearer vision of a monofocal which is good because with my vision loss due to myopic macular degeneration I would not be able to see well with a multifocal or edof.
Also know that you can choose to have both eyes the same for the best depth perception or you can have your prescriptions slightly different for a little more range.
With high myopia you are at higher risk for complications so it's good to have a really experienced surgeon.
You might find this article informative:
https://eyewiki.aao.org/High_Myopia_and_Cataract_Surgery