What are Contact Lenses?

Photo courtesy DHD Multimedia Inserting a contact lens

Contact lenses are thin transparent plastic discs that sit on the cornea. Just like eyeglasses, they correct refractive errors such as myopia (nearsightedness) and hyperopia (farsightedness). With these conditions, the eye doesn't focus light directly on the retina as it should, leading to blurry vision. Contact lenses are shaped based on the vision problem to help the eye focus light directly on the retina.

Contact lenses are closer to natural sight than eyeglasses. They move with your eye and correct the refractive error closer to the eye to allow for a more natural field of vision. They don't get in the way of your line of sight, like glasses can. Contact lenses can be worn all day, or even several weeks at a time, so you don't have to worry about putting them on and taking them off.

Contact lenses stay in place by sticking to the layer of tear fluid that floats on the surface of the eye. Eyelid pressure also holds them in place. As the eye blinks, it provides lubrication to the cornea and helps flush away any impurities that may have become stuck to the lens.

Next, we'll look at some vision problems and find out how contact lenses can correct them.