Re: RGP and large pupils

On Sep 25, 6:32 pm, "Charles" <nos...@xxxxxxxxxx> wrote:
Dr. Leukoma wrote:
On Sep 23, 7:15 pm, "Charles" <nos...@xxxxxxxxxx> wrote:
Mike Tyner wrote:
Changing the OZ might not fix starbursts around point sources in
your central vision..

OZ problems usually create rings and peripheral flashes that move
when you blink.

Starbursts sound more like surface effects, protein or crazing.

What happens to starbursts when you blink and move the lenses?

What happens if you clean your lenses right before driving?

The cornea isn't spherical. Changing the OZ changes the fit.
Peripheral curves are there to match the natural shape and to
reduce thickness.

-MT, OD

Thanks for the reply. The reason I think OZ is because it is so
obviously related to the size of my pupil. If I'm looking at a far
off light at night and it's totally dark, it'll have a big
starburst. Put some car headlights in the mix and it totally
sharpens up. I can watch the starbursts grow and shrink as the
light situtation changes. Would this be the case if it were
something else? He just recently increased the OZ size and it's
better, though not fixed. Worse in left eye too.

At night I can see pretty much the whole perimeter of something (OZ
or lens itself) in my peripheral vision. Like a halo kind of. That
itself doesn't bother me much.

I'll have to experiment with cleaning the lenses and then going out
at night. It's true that I've always had many hours of wear before
these night situations arise.

Okay, so a large OZ is good, but the trade-off is that you have a
thicker center potentially, and less lens to work with for comformat
around the edges (if I understand you right). Makes sense.

So if you were my doctor, what would you try to help fix the
problem, aside from seeing if cleaning them helps?- Hide quoted
text -

- Show quoted text -

Your aberration appears to be pupil dependent. It's probably
spherical aberration. Optics should be able to solve this problem.
You need to know the size of your dark-adapted pupil and the size of
the contact lens optical zone. It appears you don't have this
information.

The crystalline lens is also a potential source of aberrations,
although this seems unlikely in your case. There are instruments that
can measure these aberrations directly. They are called
aberrometers.

Thanks for the reply. I still need to do the experiment with cleaning
my lens in the evening and seeing if it helps. I tend to doubt it
will, but no harm in trying.

My night vision was generally excellent at night with glasses, to the
extent that my astigmatism was properly corrected. That's why I'm
noticing this so much. I assume this rules out my eyes themselves as
the problem, as opposed to their interaction with the contacts?

My optometrist seems to be acting like he's out of ideas, though I'm
only on my third try (first on the right eye). First out of the chute
were pretty good, but my left eye had some residual astigmatism. He
went to stiffer material, which pretty much fixed the astigmatism, but
the starbursts were terrible. This one has a bigger OZ, and the
starbursts are now almost equal on both. Tolerable, but somewhat
annoying.

Since I can read 20/20 in the exam room, he thinks I'm done, it seems.
Around here, the optometrists make all their money seling product, so
are they are disinclined to go into problem solving mode.

--- Hide quoted text -

- Show quoted text -

I still need to know the diameter of your dark adapted pupil and the
optical zone of the contact lenses.

.

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