To Dr. David Robins --response to your letter of twop weeks ago.

To: Dr. Robins

Thank you for your thorough answer.

And I'm an E.E. too.

I found my surgery bill. It says I had:

"cataract surgery w/iol, 1 stage (66984-RT)"

Is that not an extracapsular cataract extraction?

"Extracapsular cataract extraction" sounds like more surgery than
I had. The MD talked about taking out the cateract whole. Phaco
did not work. He did not say anything about removing the capsule.

I followed what you said about the stitching leading to the astig., but
don't you mean 10 deg and 100 deg? (rather than 80 deg),
or are the cyl angle and eyeball location measured in opposite directions,
coinciding at 90 deg?

Since the cyl went down from -4 @ 10 deg to -2 @ 10 deg over
the first few weeks, I thought the stitches dissolved at that time. You
think they just loosened. They were never removed nor even cut. You think
they should still be cut for less astig. The cyl has been fairly stable for
the 8 months after the first month, but the needed sph went more neg
by more than -1.00 diop. I sure would like the Rx to stablize. The
left eye faces cataract surgery now, with its Rx sph zooming negative and
cyl growing rapidly too.

I now see my R. optimum cyl. varying between -1.75 and 2.00 over hours. Not
a problem.

But is this kind of variation expected, given my surgery?

What about the asymmetry in quality of focus at the two meridians?
A thin line at 100 deg. focuses sharply with its best correction, but
a thin line at 10 deg. is less sharp with its best correction. This is not
a question of getting the correct Rx cyl.

Perhaps the stitches pulled something in the optical path into a
slightly non-toric shape with the higher-order variation somehow
aligned with the 10- deg meridian.

I hope you have patience for all these questions.

Thank you again,

Jack

 

Sorry - I must have missed the several posting you have made in the last
couple of weeks.

The code description (1 stage ) means the cataract and IOL were done at the
same time, rather than 2 operations. In addition, phako is sometimes
referred to as a type of extracapsular cataract surgery, since it does not
involve remving the capsule, just the innards. Whether the nucleus is
removed in 1 piece (extracapsular extraction) vs by ultrasonic
emulsification (phako) is not always mentioned in the code.

Your Rx, converted to plus cylinder, is -2.75 +1.75 @ 100 deg. Yes, I did
add wrong, and mention 80 deg, when the tight suture would have been at 100
deg.

The sutures are usually nylon, which do not dissolve in the usual sense, but
do degrade over many years. Some loosening does occur. Usually, at the 6-8
week time, on tries to reduce the astigmatism (as measured in refraction, no
necessarily the K-readings) to about 1 diopter at the LEAST. Going lower has
the risk of later slippage going the other way. Leaving it at 1.75 - 2.00 is
a bit higher than I'd like.

The issue of the sharpness at the 2 medians not being equal means the
medians are not equally displaced from the optimal focus plane, which is the
sphere error. If the sphere where correct, both lines would be slightly,
equally, out of focus. (However, the optics of using the astigmatic clock
is something I haven't had to deal with in years, some one of the
optometrists here may correct me.) The cylinder is caused by the sutures
pulling the cornea into a non-sphere.


David Robins, MD
Board certified Ophthalmologist
Pediatric and strabismus subspecialty
Member of AAPOS
(American Academy of Pediatric Ophthalmology and Strabismus)