Surprisingly, contact lenses were invented over one hundred years ago. Since then numerous improvements have been made. People who were not candidates for discount contact lenses in the past may be good candidates now. If you are interested in contact lenses in order to correct vision problems, or for cosmetic purposes, this article provides a brief overview of what contact lenses can, and can not, do for you.

The first step for people interested in getting lenses is to see an eye care professional for an examination, and to discuss the situation. Whether for vision correction, cosmetic appeal, or any other use, contact lenses are classified by the FDA as medical devices requiring a script from a licensed professional.

The discount contact lenses can correct for the same vision problems as eyeglasses and corrective surgery, including astigmatism, near-sightedness, and far-sightedness. Unlike eyeglasses, lenses provide an unobstructed field of view while remaining cosmetically invisible. Furthermore, lenses resist fogging, or becoming splotched with rain drops. As such, many people choose to wear contact lenses while playing sports.

lenses are categorized by the contact material, the duration the contact can be worn, the frequency of contact replacement, and by the design or shape. As far as materials, contact lenses are available as hard lenses, soft lenses, and oxygen permeable lenses. Having been supplanted by the other two types, hard lenses are very rare these days.

As far as the duration of time worn, lenses are available for daily wear, extended wear, and continuous wear. Daily wear lenses must be taken out each night before going to sleep. Extended wear lenses can be worn for up to a week without removal, including overnight. So-called continuous wear lenses can be safely worn for up to thirty consecutive days and nights.

However, each person may have different circumstances that require different types of contact lens usage and your eye care professional would be able to fit you for the most suitable contact lenses for your situation.

One downside of contact lenses is the need for occasional replacement due to breakdown of the contact lens material. The frequency of replacement is divided into daily disposable, disposable, continuous wear, and planned replacement. As the name suggests, daily disposable lenses must be replaced following each daily use. Disposable lenses require replacement every week or two. Continuous wear lenses must be replaced monthly. Planned replacement lenses are to be replaced on a periodic basis of one month or longer.

The design and shape of a lenses determine its intended use as a corrective appliance. The lenses are shaped spherically to correct for a single deficit, such as far-sightedness, as a bifocal lens for better vision near and far, and as astigmatism contacts to correct for astigmatism.

If you are prepared to purchase discount contact lenses, the next step is to schedule an appointment with an optometrist. After receiving a prescription, discount contact lenses are available from many sources online. A search for "Shoplens" will reveal popular selections.