What Lens Is Used for Nearsightedness?

Squinting is a good look for Clint Eastwood or Robert De Niro, but for most of the rest of us, it's a hassle. When you are nearsighted, or myopic, you have difficulty seeing in the distance without glasses or contacts. Lenses that correct nearsighted vision have special features and properties.

Function and Significance

• Spectacle and contact lenses help you see better by redirecting light rays through the lens and into your eye. Lenses work by adding or subtracting the focusing power of your cornea and crystalline lens. Nearsighted lenses are concave and are thicker at the edges and thinner in the center of the lens.

Nearsighted Lens and Diopters

• Nearsighted prescription lenses are written in minus power. A spectacle or contact lens power will have a (-) sign in front of a number, which indicates the amount of prescription needed in the lens, also called a diopter. Lens power ranges from 0.00 to 20.00 diopters or even higher and is prescribed in .25 increments. An example of nearsighted lens power is -2.00 or -2.25. The higher the number, the thicker the lens.

Material

• Most lenses for nearsighted vision are made from plastic but are available in many materials. Glass is the heaviest type of lens material and is not used very often for myopic prescriptions. Polycarbonate is an ideal material if you are nearsighted because the lenses are thinner and lighter and also more shatter resistant than regular plastic or glass.

  Another lens option for nearsighted correction is called photochromic, a lens that gets darker outdoors and lighter indoors. Photochromic lenses are useful if you have a strong prescription and do not want to switch glasses every time you go outside or inside.

Contact Lenses for Nearsightedness

• Contact lenses correct vision the same way spectacle lenses work. Contacts are made from special types of plastic and silicone and bend light to correct vision. Contacts lenses for nearsightedness are thicker at the edges than in the center, just like lenses for glasses. Your contact lens prescription power may have a slightly different number than your spectacle prescription because contact lenses sit closer to the eye and refract light differently.