Lenses | A Moment of Science - Indiana Public Media

Photocopying machines are fairly complicated devices, but the basic principal is pretty simple.

You probably have noticed that cats have slit pupils and humans have round pupils. What are the advantages of each pupil shape?

For those who strain to see both near and far, bifocals have been the answer for a couple hundred years. Until now.

Learn about the drugs put into contact lenses on this Moment of Science.

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