Eyeglasses: How to Choose Glasses for Vision Correction

Eyeglasses Decision #1: What Type of Glasses Do You Need?

There are two main types of eyeglasses. Single-vision glasses have a lens designed to help you see either close up or far away. Multifocal glasses correct both near and distance vision — all in the same lens. One part focuses for distance vision and the other focuses up close for things like reading.

Single-vision lenses

People wear glasses with single-vision lenses to solve several types of focusing problems.

• Myopia or nearsightedness. People who have trouble seeing far-away objects can wear these glasses.
• Hyperopia or farsightedness. People who have trouble seeing up close can wear single-vision glasses also.
• Presbyopia. People with good distance vision can get blurry near vision with age. This is called presbyopia. Reading glasses have single-vision lenses that help you read up close. You can buy "readers" over the counter at drugstores, bookstores, and other retail shops. You can also get a prescription for reading glasses from your eye care provider.

You will probably need to change your reading glasses prescription from time to time. This is because between the ages of 40 and 60 your eye's natural lens will continue to lose flexibility. This means you will lose more and more focusing ability.

Some people worry that reading glasses might cause their sight to worsen more quickly. That's not the case! Delaying the use of reading glasses is of no benefit.

Multifocal lenses

Glasses with multifocal lenses correct distance vision along with presbyopia.

• Bifocal lenses correct for reading on the bottom and for distance on the top. Specialized “double-D” bifocals also have segments at the top for glancing up at objects in the intermediate or near range.
• Trifocal glasses have lenses with three different lens corrections. One pair of glasses correct for distance vision, intermediate vision and near vision.
• Progressive lenses work about the same way as bifocals or trifocals. Progressives, though, have a smooth transition instead of visible dividing lines between zones. Many people prefer the invisible transition of progressive glasses. The focused areas are smaller, though, because the transition areas use more space. Progressive lenses can cause more distortion than other types of lenses. This makes these types of glasses difficult to wear for about 10% of people.
• Computer glasses have multifocal lenses designed to focus on computer screens, which are usually positioned about 20 to 26 inches away from the face. These glasses help prevent eye strain. They also help office workers to easily switch focus between different distances. This could be helpful in a conference room, where you might need to look back and forth at whiteboards, printed pages, and computer screens.

Eyeglasses Decision #2: Which Lens Materials Should You Choose for Your Glasses?

The material you choose for your lenses makes a big difference in your glasses. Eyeglass lenses used to be made only of glass, but today most lenses are plastic.

Plastic lenses

Plastic lenses are lighter and more flexible than glass. They are also safer because the lenses are less likely to shatter. These lenses have inherent UV light-blocking ability.

Polycarbonate lenses

Doctors often recommend glasses with polycarbonate lenses for sports and other activities. Polycarbonate is highly impact resistant. These lenses can often prevent eye injuries.

Trivex lenses

Trivex is a newer plastic material. Glasses with trivex lenses meet the same safety standards as polycarbonate. The advantage is that trivex lenses are less distorting than polycarbonate lenses.

High index lenses

High index lenses are thin, lightweight, plastic lenses. Glasses with high index lenses are for people who need high visual correction. Because they are thin, they reduce the “coke bottle” look that comes with thick-lens glasses.

Eyeglasses Decision #3: Do Your Glasses Need Protective Coatings?

Protective coatings for eyeglasses are available to help you keep your eyes healthy.

Anti-reflective coatings

Anti-reflective coatings reduce glare. This makes eye contact easier, prevents eyestrain, and improves your appearance. Coated lenses also allow more light to pass through. This improves your ability to see small patterns and letters. These coatings are especially helpful for people bothered by the glare of headlights and other lights while driving at night.

Ultraviolet (UV) coatings

UV coatings helps to protect your eyes from the sun's harmful radiation. You may not need this type of coating with glasses with some types of plastic lenses. Some plastic lenses block UV light without a special coating.

Polychromatic coatings

Some people prefer to wear one set of prescription glasses for both inside and outdoors. You can choose glasses with photochromatic lenses to achieve this. These lenses adjust based on light exposure. They have a darker tint in sunlight and a lighter tint indoors. A disadvantage is that photochromatic lenses do not work well in cars or airplanes. This is because windows block the light rays that trigger the change in lens tint. In some environments, it may take several minutes for the lens tint to change from dark to light.

Thanks for reading.
010@mikeeyewear.com
Cherish Chen