Types of Eyeglasses for the Nearsighted

If you cannot see things at a distance, you suffer from nearsightedness which is also called myopia. There are different types of materials used to make eyeglasses that help correct this condition. Prescription powers are written in diopters, a unit of optical measurement. If you are nearsighted, you will have a diopter power written with a minus sign by it. Understanding the specific kinds of lenses can help you choose which eyeglasses are right for you.

Plastic Lenses

• Plastic optical lenses are made from a material called CR-39, a type of resin. This kind of lens is generally recommended for people with mild to moderate nearsighted vision correction. In optical terms, this would be a prescription that is approximately 2.00 diopters or less, according to eyeglasses.com.

Polycarbonate Lenses

• Polycarbonate lenses are lighter and more shatter-resistant than plastic spectacle lenses. They are sometimes referred to as "safety lenses" because they are more impact-resistant. Because polycarbonate lenses are thinner and lighter, they work well if you need a moderate prescription, usually in the power range of 2.00 diopters or higher. Polycarbonate is recommended for children in all power ranges because children are active and more likely to need a safety-type lens.

High-Index Lenses

• If you are extremely nearsighted, high-index lenses are a good choice for you for everyday wear because they are the most cosmetically appealing. These lenses offer a different index of refractions, or IR. The higher the number, the thinner and lighter the lens. The IR is simply a calculation of the way the light bends inside your eyeglass lens to reach your eye, according to a study of hyperphysics optics at Georgia State University. Most high-index lenses are numbered from 1.56 to 1.70. Cost usually increases as the number gets higher.

Bifocals for Nearsightedness

• Around the age of 40, our vision begins to change and we become presbyopic, a correction that affects vision both near and far. People who are nearsighted can become presbyopic, too and may need bifocals to read. Bifocals for myopia are available with and without lines and may be made of plastic, glass or polycarbonate.

Using Lenses for Nearsightedness

• According to the optical lens manufacturer Varilux, the best way to get used to a prescription is to wear your new lenses as often as possible. Varilux also suggests only wearing your new prescription and not wearing your old one as this will make your adjustment more difficult.