Some Elementary Principles of Eye Care.. 

• Reading in dim light  may cause fatigue, but does not harm eyes.

• Bright light may cause disturbance,  but  does not harm eyes : Sunglasses are not necessary  !!!!

• Excessive use of eyes  may cause fatigue, but does not harm them, and "bad eyes" are not the result of overuse.

• Sitting too close to television may cause fatigue, but does not harm eyes !

• Too strong, to weak, or wrongly ground glasses may cause fatigue, but  do not harm eyes !

• Contact lenses neutralize refractive errors, but do not abolish them !

• The eyes clean themselves, and eye drops are not required unless prescribed by the physician. 

• Headaches usually do not occur because of eye strain. Organic headaches such as migraine never do !

• An eye with open-angle glaucoma does not appear abnormal !!!

• Cataract extraction is indicated only if the opacity interferes with activities.

• Persistent watering of an infant's eye suggests either congenital glaucoma or blocked tear duct  !!!

• Chemicals must be irrigated immediately from eyes with no delay to measure vision !!!

From : Frank W. Newell : Ophthalmology Principles and Concepts,
Page: 147, 4th. Edition