Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!purdue!bu-cs!husc6!rice!sun-spots-request
From: Dunstan_Vavasour@gec-epl.co.uk
Newsgroups: comp.sys.sun
Subject: Re: Severe Eyestrain--SUN Workstation problem
Keywords: Miscellaneous
Message-ID: <8904261411.AA23085@uunet.uu.net>
Date: 6 May 89 05:29:44 GMT
Sender: usenet@rice.edu
Organization: Sun-Spots
Lines: 30
Approved: Sun-Spots@rice.edu

It has recently been suggested that the 100 Hz (120 Hz in US) flicker from
fluorescent light tubes interferes with the human eye's ability to rapidly
move from one point of text to another, and can cause the eye to
"overshoot" the new point of focus. This considerably increases the amount
of eye movement involved in reading text, causing eyestrain. 

A hypothesis: Could it be that conventional (White/green/orange/whatever
on black) terminal screens have longer decay times on their screen
phosphors ? If there were to be even a very slight oscillation on the
screen brightness levels this could lead to eyestrain via the
aforementioned mechanism. The comments about colour tubes being easier on
the eye COULD result from colour phosphors having slower decaying screen
phosphors than monochrome ones. 

Someone who knows about screen phosphors might be able to totally dismiss
this hypothesis. It is quite likely, though, that the benefit of
extinguishing nearby fluorescent tubes is not only the reduction of glare,
but the removal of a light souce of oscillating amplitude.


Dunstan Vavasour                                                           
Systems Design Division                                                    
GEC Electrical Projects                       "Solving your problems       
Boughton Road                                    is our business"          
Rugby, Warwickshire, CV21 1BU                                              
Tel: (+44) 788 542144 Ext: 3535                                            
Fax: (+44) 788 60767                                                       
Email: dv@gec-epl.co.uk                                                    
       dv%uk.co.gec-epl@uk.ac.ukc (JANET)                                  
       ...mcvax!ukc!uk.co.gec-epl!dv