Contact lenses are small, concave devices used for corrective, therapeutic, or cosmetic purposes and is placed on the eye's cornea. It is first used to replace the use of glasses for people who have eye problems.
Because of this, some contact lenses are considered corrective. A corrective lens can improve a person's vision. Only eye experts prescribe corrective lens. The common eye conditions that are corrected by the lenses are near and far sightedness, presbyopia, and astigmatism.
Doctors recommend therapeutic lens so that existing conditions in the eye, such as corneal edema and ulcers, are protected allowing it to heal faster. This type of lens works by shielding the eyes from rubbing, blinking of the eyelids, and the dust and dirt in the air.
If contact lenses are used for medical purposes before, its use took a drastic turn when cosmetic contact lenses are introduced. These types of contact lens are especially designed to radically change the color, style, and even the design of the eyes. If you want to change the color of your eyes overnight, or make look like a zebra to match your Halloween costume, these are the lenses that you need.
Aside from these three, lenses can be further classified according to the material it is made of, its wear time, and its disposability. The shape and the number of its focal points are considered as well. To know more about the basics of a contact lens, read on:
1. Material. When contact lenses are first introduced, it is made out of glass. But glasses cause eye irritation, making it inapplicable for long use. And so Plexiglass, RGP, and Hydrogel lenses came about.
2. Wear Time. Some lenses have to be worn during the day only, and so they are called daily wear contacts. Before you sleep at night, daily wear contacts have to be removed. Consequently, there are also contact lenses that can be used overnight, up to a maximum of one week. These are called the extended wear contact lenses.
3. Disposability. If some lenses can be worn during the day only, some are scheduled for a single use alone. After taking it out for the night, it has to be thrown away. Some lenses though, are made to last for a week, a month, or even a year.
These are the common types of lenses, classified according to their functionality. If you are looking to wear contacts, it pays to know these things. You will not only be rightfully informed when you walk into the store. You'll be able to select the one most fitting you as well.