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Radzwill A

on 5 May 2014

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Transcript of Eyeglasses

how it works
how it's made
human perception
of light
Positive Impacts
Negative Impacts
Eyeglasses help near and far sighted people for them to see.
There are two different types of lenses: a plus and a minus lens.

A plus lens is used for farsighted people to help them see objects closer, while a minus lens is for nearsighted people to help them see far.

Using the right lens can correct the eyes to focus on a clear image.

Lenses can either be made of glass or plastic. Plastic lenses are more popular as they are much lighter than glass lenses.
Helps (near and farsighted) people see by correcting their vision
Most people who are nearsighted may experience their eyesight getting weaker and worse

Reading with glasses is bad for your vision
Eyeglasses are used to bend light rays so that they can enter your eyes and focus it on the retina.
Step 1: Start with a lens blanks
A lens that has no prescription.

Step 2: Surfacing
The lens is put in a lens lathe and a computer that has your prescription is used and layers of material of the back side are shaved.

Step 3: Fining
The lens is put on a fining machine as the lens back side is rough.

Step 4: Edging
The lens is cut down to size.

Step 5: Coatings
Lenses can then be coated to resist scratching, to block UV light or to reduce reflections.

usefulness of eyeglasses
The purpose of eyeglasses is to help people correct their vision. It is very helpful, especially if you have very bad eyesight. It makes it possible to see clearly.
Full transcript