Eyeglasses and Your Eyes
What Are Multifocal Eyeglass Lenses?
People who have more than one vision problem often need eyeglasses with multifocal lenses. Multifocal lenses, such as bifocals and trifocals, are eyeglass lenses that contain two or more vision-correcting prescriptions. In years past, you could spot a multifocal lens by the line separating the two sections. But today, multifocal lenses, called progressive lenses, can be made to look seamless.
Bifocals. Bifocals are the most common type of multifocal lens. The eyeglass lens is split into two sections; the upper part is for distance vision and the lower part for near vision. They are usually prescribed for people over age 40 whose focusing ability has declined due to presbyopia. Presbyopia is an age-related change that affects the natural lens in the eye.
Trifocals. Trifocals are simply bifocals with a third section used for people who need help seeing objects that are within an arm's reach. This additional segment is above the bifocal portion of the lens and is used for viewing things in the intermediate zone; for example, looking at a computer screen.
If you have questions about which eyeglass lens is right for you, talk to your eye doctor. He or she can help you choose the lens that best fits your lifestyle and vision needs.
Eyeglass Lens Coatings
There are almost as many eyeglass lens coatings as there are types of lenses. They include:
Anti-reflective coating. If glare becomes a problem, consider an anti-reflective coating applied to new eyeglasses. Anti-reflective coating will reduce reflections, decrease halos around light, and create a nicer cosmetic appearance.
Scratch-resistant coating and ultraviolet coating. Most eyeglass lenses today have built-in scratch resistant coatings and ultraviolet protection.
Tinted lenses. Sometimes a light or dark hint of color on the eyeglass lens can be beneficial to aid in vision. For example, a yellow tint may increase contrast and a gray tint may not alter color perception with sunglasses. A light tint can also hide the signs of aging around the eyes.
Mirror coatings. If you are looking for a purely cosmetic lens that allows the eyes to be hidden from view, then this is the coating for you. Mirror coatings come in a variety of colors such as silver, gold, and blue.