Description
Today's contact lenses have virtually eliminated the earlier hard lenses. Hard lenses were made from a material that din't allow valuable oxygen to pass through to the cornea. They had to be small (to leave the cornea as uncovered as much as possible),and their size often made blinking uncomfortable and allowed the lenses to "pop out".
Today's lenses are made from materials that allow oxygen to pass freely to the eye, allowing it to "breathe" comfortably. This enables today's lenses to be bigger in diameter, greatly enhancing comfort and peripheral vision,whilst reducing the image distortion that can be caused by some spectacles.
Soft lenses
Modern soft contact lenses are made from gel-like plastics, often with a high water content, that allow oxygen to pass freely to the eye.Because of thi, soft lenses can be made much larger which in turn makes them very comfertable and easy to adapt to. Some of the new ultra-thin soft lenses are so comfortable that new wearers can leave them in all day right from the start. New users usually find that they are only mildly aware of standard thickness soft lenses and that tolerance can be built up fairly easily so that most people are able to wear them all day within a week.
Disposable Lenses
All tyoes of contact lenses are now available on a planned replacement programme. New manufacturing techniques have made it possible for users to have a fresh pair of lenses regularly for about the same cost over a period as non-disposable lenses. Daily disposable lenses ara becoming increasingly popular as they eliminate the need for a lens care routine, but depending on the type of lens and the environment in which it will be worn, the replacement period can be anything from one day to two years.
Extended wear lenses
Most contact lenses are worn on a daily basis, being removed in the evening and put back in next morning, Special extended wear soft lenses are now available which may be recommended by your practitioner, which allow you to sleep in them. Typically they are replaced weekly or monthly.
Solutions
Information to come here