Contact lenses are produced from a substance called PMMA. Their liquid and oxygen permeability is low. It is easy to apply but it may take long to get used to. They are widely used today. In the past, contact lenses were quite big and it was difficult to use but today smaller lenses only covering the transparent layer are used. Hard lenses are very common due to providing a good image for astigmatism, easy to clean cheaper and durable.
Hard contact lenses
Posted by begum on July 5th, 2010
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Tags: advanteges of rigid lenses, contact lenses, disadvantages of rigid lenses, feautures of hard lenses, Hard contact lenses, rigid contact lenses
