Contact Lens Types
Todayís contact lenses have virtually eliminated the earlier hard lenses. Hard lenses were made from a material that didnít 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".
Todayís lenses are made from materials that allow oxygen to pass freely to the eye, allowing it to "breathe" comfortably. This enables todayís lenses to be bigger in diameter, greatly enhancing comfort and peripheral vision, whilst reducing the image distortion that can be caused by some spectacles.
Todayís lenses are made from two general types of materials:
Soft Contact Lenses are made from oxygen permeable, water-loving plastics that actually become pliable during manufacturing. Soft contact lenses contain between 30 and 80 per-cent water, depending on the type of lens. Many people enjoy the comfort of soft lenses; they are easy to adapt to and fit both comfortably and securely. There are now soft lenses to correct many types of astigmatism and presbyopia.
Most contact lenses are worn on a "daily-wear" basis. They are removed in the evening and put back in the next morning. Sleeping in your contact lenses is not advisable unless it is specifically recommended by your practitioner.
New advances in contact lenses have made it possible to have a fresh pair of lenses at regular intervals at about the same cost as wearing traditional daily-wear lenses. Frequent replacement programmes have become increasingly popular and also allow the contact lens wearer to spread the cost through monthly payments.
"Disposable" soft lenses are just what they say: after a prescribed period of time, the lenses are thrown away and replaced with a new pair.