The contact lens is placed directly on the eye to improve vision the same way glasses do without touching the eye. Two percent of all the seven billion people around the world wear contact lens. In the United States alone, 28 to 38 million people wear them. Needless to say, it is a prosperous industry.
It is a medical device and used to correct vision and sometimes for cosmetic purposes. However, most people wear them for cosmetic reasons, mainly to avoid wearing glasses. Sometimes they are frivolously worn to change eye color temporarily.
There are practical reasons for wearing them as well. Compared to eye glasses, the contacts are preferable because they give better peripheral vision. They are unaffected by snow, rain and sweat. Two eye conditions, aniseikonia and keratoconus, are helped more by wearing contacts than if they wore glasses.
The contact lenses are made to be disposable. One type is worn for a day and disposed of when removed at night. This is the shortest replacement schedule. Since they do not have to last for any length of time, they can be made thinner and lighter in weight. This makes them more comfortable.
There are extended wear lenses that can be worn continuously, even overnight. The ones that are made of innovative new materials can be worn for a month before they are taken out and disposed of. This is possible because they have a high oxygen permeability. This means the eye will remain in good health even when kept closed overnight.
The most recent material, silicone hydrogel, is having great success as the material extended wear lenses are made of. The rigid permeable lenses are heavier, require daily cleaning and last for over five years. There are wearers of these lenses that think the disposables are recommended by manufacturers because they make more profit.
Many people assume the FDA approves a replacement schedule. However, the wearing schedule is recommended by the manufacturer who makes them. The silicone hydrogel extended wear contacts deliver more oxygen to the eye.
No comments yet.