About 6 out of 10 Americans wear some kind of corrective lenses. And the runaway favorite is eyeglasses. About 8 out of 10 Americans with a prescription for vision correction choose eyeglasses.
 |
| Can Glasses Correct Vision |
The variety of eyeglasses to choose from can seem staggering. Thousands of frame styles and hundreds of lens designs are on the market. And you can buy them from your eye doctor, small optical shops, department stores, discount centers, nationwide optical chains or on the Internet. Eyeglass lenses are made of glass or plastic. Nearly 9 out of 10 eyeglass wearers choose plastic. Once you select the material, you'll be asked to make other eyeglass choices, many of them related to your lifestyle. Your eye doctor can make recommendations if you take a few minutes to discuss the kinds of things you need to be able to do with your glasses. Here are some common lens choices you may need to consider.
Lens materials
Glass. Although glass lenses are usually more scratch resistant than plastic, they can be about twice as heavy. That may be more weight than you're comfortable with, especially if you buy big frames. Another drawback of glass is that it's more prone to break or chip, though it must pass a breakage standard set by the Food and Drug Administration.
High-resin plastic. Costing about the same as glass lenses, these standard plastic lenses are made from a resin called CR-39. They will be a bit thicker than glass but about half the weight. They are also prone to scratching, and for that reason some manufacturers routinely put a scratch-resistant coating on them.
High-index plastic. Lenses made with high-index plastic are lighter and about 20 percent thinner than high-resin plastic lenses. That makes these lenses ideal for moderate or strong prescriptions. Unfortunately, they can cost considerably more than high-resin plastic. They always come with scratch-resistant coating and ultraviolet (UV) light protection.
Polycarbonate plastic. Lenses made from polycarbonate plastic are the strongest available, which makes them the preferred choice for active kids and for use in safety glasses and sports glasses. Though these lenses aren't as lightweight as the high-index lenses, they're lighter than those made of high-resin plastic. They always come with scratch-resistant coating and UV protection.
Lens coatings
Scratch protection. A clear, hard coating is applied to lenses to make them more resistant to scratching. In most cases scratch protection is automatically included with high-resin plastic and high-index plastic lenses. Occasionally it's an additional charge. It's a good idea to check that both sides of a lens have been treated because you can accidentally scratch the inside while cleaning it. Be careful where you store your glasses because in extreme temperatures the scratch-protection coating can crack and peel.
UV protection. UV rays may contribute to several age-related eye diseases, such as cataracts and macular degeneration. So when you're outside, it's a good idea to wear glasses that filter out both UVA and UVB light. High-index plastic and polycarbonate plastic lenses will have UV protection. So don't let an unscrupulous or rookie salesperson talk you into paying extra for UV protection that you've already bought.
Antireflection coating. Reflection and glare can make driving difficult, particularly at night. Antireflection (AR) coating helps block the light reflected off surfaces such as pavement, water, snow and glass. This is a big help if you have a stronger prescription, which increases glare. AR coating also reduces the light reflected off your lenses, which makes them nearly invisible. This makes the coating especially useful for public speakers or people who are frequently photographed.
 |
| Can Glasses Correct Vision |
The chemical makeup of this coating makes it harder to keep your lenses clean. And frequent, hard cleaning can rub off the coating. Try to always wipe your lenses carefully with a lint-free cloth moistened with water or a lens cleaning solution. The scratch-resistant coating is generally applied before the antireflection coating, which leaves the AR coating vulnerable to scratches. To find out more, you can check out Can Glasses Correct Vision.