Contact lenses, also known as vision-correcting contacts, are thin, rigid plastic lenses placed directly onto the eye’s surface. Contact lenses are small ocular prosthetics ordinarily used by more than 150 million individuals world-wide, and they are often worn to correct poor vision or for corrective or aesthetic reasons. Some people wear contact lenses to improve their eyesight and some wear contact lenses to alter the color of their eyes or to provide improved vision in one eye. For those individuals who wear contact lenses because of an eye condition, there are several different options available to them to help them care for their contact lenses.
Individuals with astigmatism will have to deal with a slightly different set of complications than those who have a glasses eye condition. Astigmatism is an irregularly shaped cornea, which means that the curvature of the cornea when viewed with the naked eye is slightly off-center. When an individual wears contact lenses, the individual must take great care to ensure that their contact lenses are fitting well and also that they are not rubbing against one another. In addition, individuals with astigmatism will usually experience some degree of dryness of the eye at times, which can make eye wash-off difficult, if not impossible, for some individuals. For these reasons, it is very important for people wearing contact lenses to be sure to use high quality contact lenses that fit properly and that also dry quickly so that contact lens wearers can quickly apply eye wash.
Individuals who are looking at purchasing contact lenses may be confused by the different methods that their optometrist will recommend for care of contact lenses. Your optometrist will most likely prescribe contact lenses to you that are meant to be worn overnight and that must be thrown away the morning after you wear them. Your optometrist may also prescribe specially designed lenses, called “long wear” lenses, that are meant to be worn for at least two nights in a row, then discarded the day after you wear them. If you choose to purchase disposable lenses, your optometrist may suggest to you that you also purchase some sort of lens case that can keep your new lenses from getting contaminated when they are stored in the case.
The process of wearing contact lenses begins with your eye doctor finding the appropriate pressure points for your cornea. These pressure points are located around the perimeter of the cornea and help to define where the light can reach the retina. With your cornea still slightly open, the light rays begin to enter the eye and are refracted as they pass along the cornea. When you have refractive errors, your eye will refract the rays at different rates and result in the appearance of varying colors or shapes within the eye. If you have astigmatism, your optometrist can help you select from the various forms of correction that are available.
The type of correction that you choose depends on your particular eye problems, but in general can be categorized into two types: gas-permeable and disposable lenses. Both types of correction require that you either wear a gas-permeable form of contact lens or disposable lenses may be used. In the case of gas-permeable contact lenses, your eye will only breathe through the top of the lens, which allows a small amount of air to get through the pupil. This is why some people wear gas-permeable contact lenses during sports such as football, basketball and baseball. The risk of these types of complications includes a reduced ability to heal tears, damage to the cornea and infections. The risks of disposable lenses include eye infections, reduced vision quality, and even blindness.
Contact lenses require daily-wear lenses that are removed once you wear them for a certain period of time. Daily-wear lenses may be made from several different materials including polycarbonate, high index lenses, traditional rigid gas-permeable contact lenses and extended-wear. Contacts that are made from polycarbonate can provide softer contact lenses with greater comfort as they are more durable. Poly-carbonate lenses also give out a dimpled appearance to the eye and thus are often only worn overnight. High index lenses are great for anyone who is experiencing astigmatism and other problems associated with the cornea but may not be comfortable with the softer extended-wear contact lenses that are available.