Contact lens
device · 1949 · Digital age
A lens worn on the cornea.
Principles and materials it uses
- Plastic — is made of. Hard lenses are PMMA, soft ones hydrogel.
- Refraction of light — uses. It corrects the refraction of the eye.
- Soft hydrogel material — is made of. Silicone hydrogel that lets oxygen through.
History: what it evolved from and what it influenced
- Glasses — evolved from. A lens right on the eye.
What it is a kind of
- Lens — is a kind of. A lens.