From: francis@ircam.fr (Joseph Francis)
Subject: Re: Can't wear contacts after RK/PRK?
Keywords: radial,keratotomy,contact,lenses
Organization: IRCAM, Paris (France)
Lines: 45

In article <1993Apr16.063425.163999@zeus.calpoly.edu> dfield@flute.calpoly.edu (InfoSpunj (Dan Field)) writes:
>I love the FAQ.       
>
>The comment about contact lenses not being an option for any remaining
>correction after RK and possibly after PRK is interresting.  Why is
>this?  Does anyone know for sure whether this applies to PRK as well?

I've had PRK.

I would suggest asking a doctor about contacts. Mine said yes to
contacts. I think the scars from RK would preclude contacts.

>Also, why is it possible to get a correction in PRK with involvement of
>only about 5% of the corneal depth, while RK is done to a depth of up to
>95%?  Why such a difference?  I thought the proceedures were simmilar
>with the exception of a laser being the cutting tool in PRK.  I must not
>be understanding all of the differences.

No. RK makes radial cuts around the circumference of the cornea, up to
8 I think, and these change the curvature of the cornea through stress
chages. PRK vaporizes (burns) away a thin layer from the front of the
cornea making the optical axis of the eye shorter. The laser doesn't
cut in PRK, it vaporizes. In RK, the eye is cut into.

>In the FAQ, the vision was considered less clear after the surgery than
>with glasses alone.  If this is completly attributable to the
>intentional slight undercorrection, then it can be compensated for when
>necessary with glasses (or contacts, if they CAN be worn afterall!).  It
>is important to know if that is not the case, however, and some other
>consequence of the surgery would often interfere with clear vision.  The
>first thing that came to my mind was a fogging of the lense, which
>glasses couldn't help. 
>
>would not help.

I find my vision is more clear for some things, and less clear for
others, only at night. I notice a definite haloing at night in the
darkness when I look at automobile headlamps, though this is not
something I spend inordinate amounts of time doing. For ordinary
things, my vision, in particular having a fully-operating peripheral
vision, is clearer than with glasses, or contacts.

-- 
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| today; American - All American; doing, a bit so, and even more so.
