264 IMPORTANCE OF OUR EYES 



erate intensity are preferred to the stronger lights. Fine 

 print and the use of glossy or colored papers are also matters 

 that we should avoid. The use of large type for young 

 children is particularly important, because the eye then is 

 more elastic, and extra strain placed on the muscles of the 

 eye may lead to permanent harm to the curved surfaces. 



Color blindness. In order to qualify as an engineer 

 on the trains, or as pilot, where it is necessary to distin- 

 guish colors, one must first submit to a test for color blind- 

 ness. 1 From three to four per cent of boys and about 

 one per cent of girls are color blind. This is one reason 

 why some boys cannot match colors as well as girls can. 

 The most common form of color blindness is the inability to 

 distinguish between red and green. 



Suggestions for the care of the eye. i. Do not sit so 

 that direct light reflected from book, paper, or highly 

 polished floors will cause a glare. 



2. Do not sit facing strong artificial or natural light. 



3. Do not sit so that your shadow falls upon your work. 



4. Do not use a flickering light. 



5. Do not read on a train or other moving conveyance. 



6. Adjust the intensity of the light to your needs. 

 Strong light is needed to read fine print. 



7. Do not use the eyes when they ache or when you 

 yourself are fatigued. 



Correction of defects. If you have discovered from 

 the laboratory exercises that you have eye defects, go at 

 once to an oculist and have glasses to correct them. 



If the eyes are red or inflamed or if water runs from 

 them, or if the lids are sore, see a physician at once. Avoid 



1 Holmgren's woolens and Westcott's color slide are useful in detecting 

 color blindness. 



