IOL power meaning please

Posted , 6 users are following.

My sister had two dense cataracts removed in May and July. The only information she has is a card to give her optician when she visits for prescription glasses for distance about 6 to 8 weeks after the July operation

The first card is for the Right Eye.

It says::

CT Asphina 409MP (which is a type of IOL lens)

ØT = 11.0             Ø body = 6.0

Right eye D +23.0

The second card is the same except

Left eye  D: +23.5

I was wondering if someone could give me any information on the meaning of those measurements with the limited information available. She wasn't told anything about type of lens or whether it was for distance or near vision. 

Her previous history was that she didn't need glasses as a child, but over the last 10 to 15 years she needed both distance and reading glasses getting progressively stronger but she doesn't know the strength.. I was unaware that she was almost blind in one eye and the "good one" had a permanent smudge in front of it. She thought her clear glass was frosted!

The surgeon told her she let her cataracts grow too dense before having them removed. . (I believe it is more difficult to measure for IOL power if cataract is too dense).

She was scared after first surgery on right eye because she couldn't read the numbers on the wall clock in a classroom and could only read medium sized print. However she was almost blind before the operation so it was a great improvement on pre-op.

But WHAT IF THE OTHER EYE HAD THE SAME RESULT? We both foolishly thought that all cataract operations were a magical process that gave you perfect vision for both near and far!!!!    This was a rude awakening! 

Luckily the other eye was a much better result. She can now drive around quite confidently in her local area and will require prescription glasses to see further into the distance in order to read distant signs.  She needs +1 reading glasses to read the paper. Everything is much clearer and colours are sharper than she has seen in years, so she is happy with the outcome considering she left it so late.  

As I, too, have early stage cataracts, I'm trying to understand what happens.

0 likes, 9 replies


9 Replies

  • Posted

    Hi Mary - did your sister have regular yearly visits to her optometrist?  Usually that is the place one learns they have the beginning of a cataract and it will be checked at each subsequent visit to see if it is worsening.  A lot of countries do the cataract surgery for free once your vision is 20/40 or worse.  Sometimes it can take years for the cataract gets bad enough to need surgery and other times it progresses rapidly.

    The lens type isn’t one I am too familiar with (not used or available in Canada where I live) but upon looking it up it is manufactured by Zeiss and is a Monofocal, aspheric (aberration neutral) lens made of Hydrophilic acrylic (25%) with hydrophobic surface properties.  Optic diameter of 6mm which is pretty standard.

    The numbers are the diopter used in each of the lenses.  That lens comes in increments of .50 diopters (also standard for most IOLs)

    If you are concerned about your own cataracts ask your optometrist for a referral to an opthamologist.  An opthamologist will be able to exam your eyes and let you know if they are bad enough to warrant surgery at this stage.

    Report Reply
    • Posted

      Yep, thats why annual eye exams are important - can detect cataracts years before they affect the vision, so you have lots of time to plan ahead.  My right eye's cataract was detected nearly 10 years before I needed the surgery and even by then it wasn't very dense yet just affected the vision enough that it wouldn't correct to better than 20/40 or so.

      Report Reply
    • Posted

      That why I was shocked to learn I had cataracts bad enough to need surgery when the year prior’s exam nothing was said.  I think my case is more rare - most likely they are slow to develop.
      Report Reply
  • Posted

    Cataract surgery results can vary quite a bit, there is the unpredictability of the healing of the eye and that can sometimes leave some residual astigmatism.  Also the IOLs come in 0.5D steps, so that can mean an error of 0.5D is possible and even more if the measurements of the eye are a little off like in the case of dense cataracts.

    So eyeglasses may still be needed after the surgery to correct the refraction errors remaining, or an alternative is getting laser cornea surgery to try to correct the errors, but that can introduce night vision artifacts.

    There is no perfect artificial IOL lens yet, so no guarantee on the results.  Most likely will need eyeglasses in most cases at least for some forcus range(s) like near or far.

    Report Reply
  • Posted

    The IOL prescription, which your sister received is useless to your optometrist when he/she tried to prescribe glasses. 

    This IOL prescription was of benefit to the ophthalmologist for the purpose of procuring what he/she needed for your sister, would have been useful to tweak the IOL prescription for the second eye, would be useful if she decided to have the IOL changed (not recommended), but there is no benefit in figuring out the glasses prescription which she will need. The glasses prescription will be based by an eye examination and looking at the eye chart, just like she had before she developed the cataract.

    Report Reply
  • Posted

    Well, I think you would have to be an eye doctor to know what those number mean!   I'm glad the other

    eye was a success!! 

    Report Reply
  • Posted

    My surgeon said +20.0 is a plano lens..simply corrects for cloudy cataracts, needing no vision Rx.

    I had +13.0 lenses put in my eyes to correct a -5.0 eye glass correction for being mainly nearsighted.

    My guess is that the +23 you mention was for a farsighted Rx.  Maybe glasses were about +2.0 Rx prior to cataract surgery?

    Report Reply
  • Posted


    I am having cataract surgery next week & knew  I was getting cataracts over 12 years of yearly eye exams. About 2 years ago vision in 1 eye got blurred & went to my local eye Dr.who wanted to do cataract surgery. I am having a highly regarded surgeon do the operation. Just got one of my questions answered by him:

    Is my cataract considered dense or a brunescent cataract?

    His answer:

    Yes, very dense and brunescent in the left eye - I will use techniques to mitigate the increased risk of cataract surgery on a brunescent lens. In my practice, I frequently operate on brunescent cataracts.

    Report Reply

Join this discussion or start a new one?

New discussion Reply

Report as inappropriate

Thanks for your help!

We want the forums to be a useful resource for our users but it is important to remember that the forums are not moderated or reviewed by doctors and so you should not rely on opinions or advice given by other users in respect of any healthcare matters. Always speak to your doctor before acting and in cases of emergency seek appropriate medical assistance immediately. Use of the forums is subject to our Terms of Use and Privacy Policy and steps will be taken to remove posts identified as being in breach of those terms.

newnav-down newnav-up