Almost guaranteed.

Better, maybe the best compromise.

-MT, OD

I don't believe that glasses would work with one eye plano and the
other -6D.  (Your mother would probably have double vision with
glasses.)  She would have to wear a contact lens in one eye to have
comfortable, acceptable vision.

If the eye with the cataract were corrected to -4D (and the other was
-6D), glasses would probably work.  But what a missed opportunity to
finally have good uncorrected vision (in my opinion, anyway).

I suspect that your mother is anticipating that cataract surgery is
much worse than it is.  I found it to be a painless procedure.  I only
had to spend about 90 minutes in the surgery center that morning, and
the surgery itself took only about 10 minutes.  After lunch that day.
I walked over to the local multiplex to see a movie.  (I hated the
thought of wasting an afternoon off work.)  But the eyes are your
mother's, and she should have the final say about how she wants her
vision corrected.

The problem is not that she would see so much better (corrected) in the right
eye than the left eye, instead it will be the amount of discomfort from the
brain trying to fuse, two different size images. The discomfort can be severe,
with the potential for diplopia, that's remedied only by occlusion or contact
lens. And that's just the distance vision. There will be additional
complications with the near vision, although these may be minimized with
specially made glasses (Slab).  

I wear a -4.50 Rx and have very clear vision (corrected). Moreover, I read
comfortably in bed at night without glasses, and can see very small objects and
very fine print uncorrected. Ask your mom if she takes her glasses off on
occasion when performing near tasks like reading the instructions on
medications. Ask her if she would prefer to put on reading glasses along with a
magnifier instead.  

Too much of a compromise unless it's short term. I don't understand the
compromising- unless your mother strongly desires to reduce her reliance on
eyeglasses. If true, then she needs to have both eyes done in a relatively short
time frame, and the Rx goal should be about -.50 sphere equivalent. If not, then
compromise should not be in your surgeons lexicon, at least not in this case.

-6.00 and  plano won't work. Her brain might accept -6.00 and -2.00 without
diplopia but there would still be some degree of discomfort. Moreover, there
would still be a need for specially made lenses to decrease the discomfort when
reading. I don't see why -2.00 should be on the table- unless the fellow eye
will get an IOL in the very short term, which seems unlikely.

Strong consideration should be given to matching, especially on the vertical
meridian, the Rx of the fellow eye. The result will be comfortable vision (if
there are no complications with the surgery) at all distances- essentially no
change from the pre to post-op.

Hope this helps

Robert Martellaro
~~~~~~~~~~~~~~~~~~
Optician/Owner
Roberts Optical
Wauwatosa Wi.
~~~~~~~~~~~~~~~~~~
"Science is a way of trying not to fool yourself."
- Richard Feynman

I am not a doctor, but was in a similar situation just a few months
ago.  I asked the same questions, did my research and reached my
conslusions.  The following is my opinion, based on the above.

First, I would delay surgery on the non-cataract eye until it becomes
necessary. Any surgery has some risk involved, even if only minimal,
but why take the risk as long as it can be avoided?

Given this, I would go for a difference of  -2D between the eyes, i.e.
she'll have -6D in one eye and -4D in the other.  This will improve
your mother's vision in the operated eye without causing any problems
of disparity.  Why not take advantage of the opportunity?  Please note
that a disparity larger than 2D will cause unwanted problems that
would force her to operate on the other eye that does not need a
cataract removal at this time.  Also be aware that the results of the
surgery in terms of visual acuity cannot always be predicted with
accuracy and they depend on the position that the IOL will eventually
settle on within the eye.

When your mother needs a cataract surgery on the second eye, have -4D
IOL, aiming to leave her at -2D.  Thus she'll end up with the first
eye at -4D and the second at -2D -- again a tollerable difference
resulting in improved vision.

Your mother will still need eyeglasses (or contacts) for some
activities, regardless of what course of action she chooses.  Even if
she does the two eyes now and achieves 20/20 vision in both, she'll
need reading glasses, and perhaps another prescription for mid-range
activities.  It is my opinion that the mid-range (computer, TV,
sitting with family and friends, cooking, etc.) is the most important
range in which most of us spend most of our time, and the desire to
achieve 20/20 with no ability to accommodate is not justified, giving
us freedom of glasses when driving or hunting, but short for all other
activities.

Not everybody would agree with me, but please consider my advice and
let us know what you decided.  Good luck to your mother.

Thanks to Mike, Jane, Robert and Ms Brainy for replying.  I had some
follow up questions but then I looked and found a trove of background
material here on cataract surgeries by y'all and others, so I'll read
that.

Armed with the helpful ideas here, I emailed the surgeon and he wrote
back this morning saying he could do -4.50, instead of -4.0 for margin
of safety, then do -2.5 or -3.0 on the fellow eye whenever later,
which "would allow the fellow eye to read without glasses."  I think
my mother should be comfortable with this option that won't
necessitate immediately surgery on the good eye.

Follow up questions, Ms Brainy brought up the issues of accommodation
and distance.  I guess keeping the fellow eye natural will preserve
whatever accommodation there is?  (don't know if she has an ADD for
reading.)  about distance, this is not something i had thought
carefully about.  i had been willing to leave it in the surgeon's
hands.  but i should ask.  is the default IOL correction for
"distance" far distance?  and is mid-distance a more practical
distance and something that has to be specifically asked for?

Robert, 'matching the fellow Rx along the meridian axis' -- how does
the surgeon do that?  by selection of the IOL?  positioning?
incisions?  would it still matter for gapping -2.0 or -1.5 as we plan
to do here?

thanks,
Ming

btw, Feynman rules :-)

I encounter this situation no uncommonly.

Firstly, most myopes I have encountered do not like being plano afterwards,
unless they are sports types who really want plano outdoors. Most are better
off being slightly myopic, in the -0.75 to -1.00 range, so indoors, without
glasses, they can function pretty well. Plano, around the house and kitchen,
is still blurry for the typical indoors distances. This would still give a
large anisometropia if the other eye is -6D.

Secondly, if the other eye is rather clear, I would first try to find out if
they can wear a contact lens. This is done in the non-operative eye, so it
can be made about the same power as the operated eye, allowing one to use
equal glasses. That is, if I plan to make the operated eye -1D, I would use
a -5D in the other eye, leaving about -1D for each eyeglass lens. This does
take time, and has to be done in advance of surgery, of course.

If a contact cannot be used, and the other eye is a long way off from
surgery, I would then recommend making the operated eye no more than 2D from
the unoperated eye, aiming for -4 or -4.50, as mentioned in a later post. I
would encourage not doing this, if the contact can be used, so I often do
take the long road of trying a contact, unless the pt really does not want
to try, or if they have experienced conacts before, and failed.


David Robins, MD
Board certified Ophthalmologist
Pediatric ophthalmology and adult strabismus subspecialty

On 9/13/07 1:10 PM, in article
1189714253.734339.208780@r29g2000hsg.googlegroups.com, "FourEyes"
<minger@gmail.com> wrote: