 Glasses correct and improve vision  The Lenses on the glasses increase the focusing power of the cornea of the eye.  They correct nearsightedness, which is when people cannot see things clearly when they are far away.  They also correct Farsightedness, which is a person cannot see things when they are Close up.

The lenses are the part of the glasses that help correct the vision. They are often made of glass or clear plastic. The frame is the part of the glasses that holds the lenses and also helps to keep the glasses on your head. They are curved so it can be attached to your ears to hold it on your face. Frames are made of a wide variety of materials. They are most commonly made of Monel Metal, Zyl, or Nylon Based Plastics.

Glass Lens Pros It can be made in any color imaginable It is extremely scratch resistant It is extremely inexpensive Cons It is very heavy Plastic Lens Lighter than the glass lens Cons Are more likely to scratch than a glass lens Glass Lens

o They are often made of a mixture of several metals called Monel. o It is corrosion resistant o Malleability: the ability to be permanently shaped or bent without cracking or breaking. o They are hypoallergenic.

 Zyl Can be made in any color desired extremely lightweight  Nylon based plastics are also strong and flexible, but cannot be made in a wide variety of colors.

 There is no known inventor, but glasses were created some time between 1268 and  They were first seen in Italy.  They originally were very tightly attached to people’s noses or held by hand instead of ear held/hanging glasses.  The Lenses were made out of quartz and the frames were made of bone, metal or leather.  We now use more clear, lighter materials for the lenses such as plastic because they are more convenient.  For the frames, we now use extremely light, colorful frames made from materials like plastic and mixed metals, because they look better and are more comfortable to wear.

FrameLens

Author Unknown. Children's Hospital Boston. Web. 21 Oct Morgan, Erinn, and Gina White. All About Vision. Web. 22 Oct Gorman, Tim. Ezine Articles. Web. 21 Oct Glass, Don. Moment of Science. Web. 24 Oct