Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site unc.unc.UUCP Path: utzoo!linus!philabs!cmcl2!seismo!harvard!talcott!panda!genrad!decvax!mcnc!unc!fsks From: fsks@unc.UUCP (Frank Silbermann) Newsgroups: net.med Subject: Re: Reading in bad light Message-ID: <114@unc.unc.UUCP> Date: Fri, 9-Aug-85 16:39:13 EDT Article-I.D.: unc.114 Posted: Fri Aug 9 16:39:13 1985 Date-Received: Mon, 12-Aug-85 08:21:55 EDT References: <1528@trwrba.UUCP> <1360@cbosgd.UUCP> <247@weitek.UUCP> Reply-To: fsks@unc.UUCP (Frank Silbermann) Organization: CS Dept, U. of N. Carolina, Chapel Hill Lines: 23 In article <247@weitek.UUCP> neal@weitek.UUCP (Neal Bedard) writes: > >With adequate light the pupil is smaller, resulting in a greater depth of >field. The net effect is that the eye has to accomodate less - very >important in warding off eye strain during extended periods of close work. >By the same token, one should not do near work at too close a distance: back >away from the work as far as comfortable, and/or use reading glasses. Both >tactics reduce the amount of accomodating the eye is required to do. > >Low light levels also reduce visual contrast, with similar eyestrain results. > >Then there are video terminals...... > >-Neal B. Doctors disagree on whether close work increases nearsightedness. If close work does actually encourage nearsightedness, then close work under dim light would be even worse, as the reduced depth of field prohibits "cheating" (under bright light, the eye could perhaps focus for 5 feet away and still be sharp enough to read 2 feet away). Frank Silbermann