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From: dr@ski.UUCP (David Robins)
Newsgroups: net.med
Subject: Re: Radial Keratotomy -- WARNING!! --
Message-ID: <212@ski.UUCP>
Date: Mon, 11-Nov-85 15:13:41 EST
Article-I.D.: ski.212
Posted: Mon Nov 11 15:13:41 1985
Date-Received: Wed, 13-Nov-85 07:19:54 EST
References: <203@bnrmtv.UUCP> <419@graffiti.UUCP>
Distribution: net
Organization: Smith-Kettlewell Institute, S.F., CA.
Lines: 34

> > resultant far-sightedness may need to then be treated.
> 
> A lot of people, particularly short-sighted people, tend to get more far
> sighted as time goes by anyway. Have the studies corrected for this (probably,
> but it's best to be sure)?

Near-sighted people do *NOT* become far-sighted at time goes on.

They do become presbyopic, as everyone does as they get older (past 40
or so), but this does not alter their distance refraction.  Presbyopia
is age-related decrease in accommodation, or ability to focus the eyes
from the relaxed distance focal point, to the accommodated near focal
point for reading.  Near-sighted (myopic) persons often become
presbyopic at a later age than normal (emmetropic) persons.  In
addition, if someone is very myopic, the minus lens they wear slightly
decreases the accommodation needed for a given near distance, due to
the optics involved.

{Presbyopia is when one has trouble reading at the normal reading
distance, but can read by holding the material farther away (at least
until one's arms cannot hold it far enough away for comfort)!}(get
longer arms? (:-).

The R-K studies follow the distance correction, which is a function of
the optics of the eye, rather than the accommodative reserve.
-- 
====================================================================
David Robins, M.D. 
Smith-Kettlewell Institute of Visual Sciences
2232 Webster St; San Francisco CA 94115
415/561-1705
			{ihnp4,qantel,dual}!ptsfa!ski!dr

The opinions expressed herein do not reflect the opinion of the Institute!