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From: werner@aecom.UUCP (Craig Werner)
Newsgroups: net.med
Subject: Re: Reading in bad light
Message-ID: <1827@aecom.UUCP>
Date: Sat, 3-Aug-85 02:03:29 EDT
Article-I.D.: aecom.1827
Posted: Sat Aug  3 02:03:29 1985
Date-Received: Sat, 3-Aug-85 21:50:02 EDT
References: <1528@trwrba.UUCP>
Organization: Albert Einstein Coll. of Med., NY
Lines: 24

> This business about vision being damaged by reading in poor light
> has always seemed like an old wive's tale to me.  

	In dim light, with the pupil dilated, the lens has to be adjusted
more finely due to the reduced depth of field (this is a property of optics,
not of medicine) Whether this damages the focusing mechanism, I don't know.

	The follow anecdote, however, is something I just had to relate to
my mother, who has been yelling at me for reading in dim light for years, as
soon as I heard it in a lecture from a Retina specialist (a branch of
Opthmamology):
	"The process of projecting the image on the retina and turning into
a chemical signal generates a lot of heat, which is helped to dissipate it
by the underlying Chorion.  However, too intense light can overcome the
capacity of the system. So, IT'S PROBABLY NOT A GOOD IDEA TO READ IN TOO
*BRIGHT* A LIGHT OR YOU'LL RUIN YOUR EYES."

[Emphasis added by me, the cap's is an exact quote, the rest is less so]
[The irony need not be added]

-- 
				Craig Werner
				!philabs!aecom!werner
		"The world is just a straight man for you sometimes"