Uh-oh, it looks like your Internet Explorer is out of date.
For a better shopping experience, please upgrade now.
How can people become blind even if their eyes are in perfect condition?
This can happen if there is damage to the part of the brain that controls sight.
Inside, You'll Find:
How glasses and contact lenses work
Diagrams, a time line, photos-and some tricky tricks for your eyes
Surprising, True facts that will shock and amaze you
Table of Contents
1 Sight and Light What does light have to do with seeing? 7
2 Working Together Why doesn't it go black when you blink? 15
Optical Illusions Can your eyes play tricks on you? 26
3 When Things Go Wrong What did Benjamin Franklin do to help people read? 29
4 Life Without Sight How does vitamin A help you see? 35
5 Stand Guard! Why must you never look directly at the sun? 41
True Statistics 43
Important Words 46
About the Author 48