There are a variety of choices in eye glasses lenses and sunglasses lenses that are designed to fit your lifestyle. Are you very active (polycarbonate lenses)? Are you in the sun often (UV protection, sun-sensitive lenses)? Do you drive at night (anti-reflective coating)? The following list gives you an overview of the most common eye glasses lens choices and options, but don’t let this list overwhelm you.

Most prescription lenses are single vision lenses. Single vision means that the entire lens is designed for one focal length, usually distance vision. Reading glasses have single vision lenses designed just for reading. You are meant to use single vision lenses just for distance, or just for reading, or just for computers, but not for more than one of these. Lenses that are designed to help you see different focal lengths are called “multifocal” lenses—bifocal, trifocal, and progressive lenses.

Progressive lenses are multifocal lenses, and are also known as “no-line bifocals”. Progressive lenses have three viewing areas—near, intermediate, and far—so that you do not need to remove your glasses when looking from one area to another. The distance portion of the lens is at the top, the intermediate portion of the lens is in the middle, and the reading portion of the lens is at the bottom. Follow this link to read more about progressive lenses. There are some restrictions on the type of frame you can use with progressive lenses; follow this link to read about eyeglass frames.

There are no visible lines separating these viewing areas, which is cosmetically appealing to many people. However, in order to remove the visible lines, it is necessary to create large areas of the lens that cannot be seen through. For example, in each side of middle part of the lens the lens is blurry, so you are required to turn your head in order to see to either side of the center of the middle of the lens. Changing your habits so that you move your head instead of your eyes is called your “adjustment”. Some people become dizzy or nauseous during their adjustment period, and some people never adjust.

Bifocal lenses have two viewing areas—near, and far—so that you do not need to remove your glasses when looking from one area to another. The distance portion of the lens is at the top, and the reading portion of the lens is at the bottom. There is a visible line between the areas. There are several different types of bifocals which may locate the reading portion of the lens in a different place at the bottom of the lens.

Trifocal lenses have three viewing areas—near, intermediate, and far—so that you do not need to remove your glasses when looking from one area to another. The distance portion of the lens is at the top, the intermediate portion of the lens is in the middle, and the reading portion of the lens is at the bottom.

Most lenses are plastic, but the least expensive plastic used for eyeglass lenses is called hard resin lenses. Hard resin lenses are good for everyday use. These lenses have the least distortion of any non-glass lens. For children or active adults engaged in sporting activities, we strongly recommend polycarbonate (impact resistant) lenses. If the sphere on your prescription is +/-2.00 or lower, you will not benefit from the more expensive “thin” lens types (high index, or aspherics).

If the sphere on your prescription is higher than +/-2.00, you will benefit from the selection of a “thin” lens type. If the sphere on your prescription is higher than +/-4.00, we recommend a “thin” lens type. Thinner lenses have three advantages: they do not look “thick”, they do not magnify or minify your eyes when seen by others, and they are lighter.

Polycarbonate lens material is the best choice for children or active adults. Polycarbonate lenses are virtually shatterproof, provides the best eye protection of any lens, and includes 100% UV protection inherently. If the sphere on your prescription is +/-2.00 or higher, you should choose polycarbonate lenses. Polycarbonate lenses are very difficult lenses to tint and are not recommended for people who want custom dark sunglass lenses (we suggest Trivex lenses in this case). The suggested prescription range for polycarbonate lenses is plano (0, no Rx) to +/-8.00 sphere.

High index lenses are good for people with prescriptions over +/-4.00 sphere, because they are thinner and lighter. Thinner lenses have three advantages: they do not look “thick”, they do not magnify or minify your eyes when seen by others, and they are lighter. The suggested prescription range is +/-4.00 to +/-8.00 sphere. Thinner, lighter and more expensive than mid-high index or hard resin lenses, high index lenses are a good choice for every day use.

Polarized lenses are tinted lenses that block vertical light from hitting your eye and causing eye strain. Hunters, boaters and fishermen, golfers, and drivers are the most common users of polarized lenses. Any surface can create glare in sunlight, including water, sand, snow, windows, vehicles, and buildings. Polarized lenses ease eye stress and fatigue in the sun, and lenses are available in several color and density options. However, in some situations, glare can be beneficial. For example, polarized lenses could make it difficult for a driver to see ice on the road, or for a skier to see ice on the ski slope, or for a seaplane pilot to see the water when landing.

Polarized lenses function similar to window blinds with horizontal slats when open. You view the slats on the edge so they are very thin, and these edges hold the tint color. Polarized lenses block the vertical light that tries to enter your eye from down below or up above, and it only allow the horizontal light to pass through the lens.

Also known as photochromic or transition lenses, sun-sensitive lenses automatically darken to a moderate shade when they are exposed to the ultra-violet rays of direct sunlight. When the direct sunlight is removed, the lenses lighten again.

A photochromic lens sounds better on paper than in practice. First, the lens darkens only in direct sunlight, because the lens needs direct exposure to ultra-violet light. So if you are wearing a hat, or if it is cloudy, the lenses may not darken enough (if at all). Lenses only partially darken inside an automobile, since most auto glass has UV protection. Second, it could take up to eight minutes for lenses to transition from dark back to clear. So if you are in-and-out of the sun, the lenses may not be dark—or clear—when you want them to be. Third, photochromic lenses do not become completely clear indoors, but retain a light tint that may not appeal to people who want completely clear lenses indoors. Several manufacturers claim that their sun-sensitive lenses become completely clear indoors, but we have not yet tested a lens that does become completely clear indoors.

AR coating goes on both sides of an eyeglass lens, and on the backside of a sunglass lens, and it allows light to pass more freely through the lens. Anti-reflective coated lenses help to reduce eye fatigue in many situations, particularly while viewing computer screens and driving at night. Normally, approximately 8% to 10% of light is reflected away from the lens, “robbing” you of valuable detail for the eye. Also, as this light is reflected off the lens surface, it creates more glare that further impairs your vision. AR coated lenses allow approximately 99% of available light to pass through without interruption, thereby reducing glare considerably.

Actors and newscasters like anti-reflective coated lenses because it greatly reduces the glare reflected from camera lighting and flashes. Anti-reflective coated lenses makes it easier for other people to see the wearer’s eyes, and it makes it easier for the wearer to see through the lens.