Description

This article is from the Vision and Eye Care FAQ, by grants@research.canon.com.au (Grant Sayer) with numerous contributions by others.

3.1 Difference between soft and hard contact lenses

Soft lenses are manufactured from a plastic hydrogel polymer,
HydroxyEthylMethacrylate (HEMA) which has a varying water content
(38% - ~70%). Lens size is between 13.00 and 14.50mm. Centre thickness
from ~30um

Hard contact lenses are manufactured from a rigid material,
PolyMethylMethacrylate (PMMA). This material can be combined with other
plastics to increase the oxygen permeability. Lens size is between

 

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health, vision, eye care, contact lenses, spectacles, eyecare, prescriptions, sunglasses, surgery