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65 Raymond Road
(across from REI)
West Hartford, CT 06107
Brian Mann, OD PC
Independent Doctor of Optometry
Call (203) 557-8440 to schedule an eye exam
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 dont let this list overwhelm you.
When you use our Lens Wizard, it will guide you through the process so you can easily make the best choices for you and your lifestyle. If you would like to learn more about choosing eye glasses lenses to fit your lifestyle, preferences, and bank account, follow this link to prescription glasses.
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 lensesbifocal, trifocal, and progressive lenses.
Progressive lenses are multifocal lenses, and are also known as no-line bifocals. Progressive lenses have three viewing areasnear, intermediate, and farso 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 areasnear, and farso 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 areasnear, intermediate, and farso 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.
Frames with a rimless design have no frame around the lens. Rimless eyeglasses lenses come in three pieces (two temples and the nose part). The lenses are actually part of the strength of the frame, so it is important to only use polycarbonate or Trivex or high index lens material on rimless glasses.
Mounting lenses into rimless frames is tricky and requires a skilled and experienced technician. Each lens must be drilled perfectly so that the frame fits snugly into the lens. A poorly mounted rimless frame will begin to rattle, and then eventually crack the lens. If you purchase a rimless frame and lens at the same time from eyeglasses.com, we do not charge extra to mount the rimless lenses. However, because rimless lenses require a significant amount of additional labor for lens installation, we do charge an additional fee to mount replacement lenses into a rimless frame that you send us.
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.
Trivex is a new plastic lens material that is being used as a substitute for polycarbonate lenses. Trivex is optically superior to polycarbonate and it is lighter. Like polycarbonate it provides 100% UV protection and it is extremely durable. Most importantly, Trivex is a great substitute for polycarbonate lenses that need to be tinted, because Trivex can be easily tinted but polycarbonate cannot. Trivex is much better suited for tinting and is an excellent choice for rimless drill mounted frames. The suggested prescription range is Plano (0, no Rx) to +/-8.00 sphere.
Trivex may be slightly thicker than polycarbonate lenses, but due to its specific gravity the weight will be similar.
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 darkor clearwhen 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 wearers eyes, and it makes it easier for the wearer to see through the lens.
Flash mirror lens coating applied to the outside of a lens helps to deflect reflected light from entering the eye. However, the flash mirror lens coating does not reflect all light the way that a pure mirror lens coating does, so in certain lighting conditions other people can see your eyes. It is important to know that the wearer does not see the flash mirror coating from the inside, but only sees the lens tint. For example, if the lenses had a brown tint with a blue flash mirror, the wearer would see only brown, and other people would see only the blue flash mirror. This is a useful combination because, optically speaking, blue is the worst tint for seeing objects clearly (brown is best), but blue is fashionable; so the wearer gets the benefit of seeing through a brown tint as well as the benefit of having other people see only the blue flash coating.
A pure mirror lens coating applied to the outside of a lens helps to deflect reflected light from entering the eye. The outside of the lens looks just like a mirror. It is important to know that the wearer does not see the mirror coating from the inside, but only sees the lens tint. For example, if the lenses had a brown tint with a blue mirror, the wearer would see only brown, and other people would see only the blue mirror. This is a useful combination because, optically speaking, blue is the worst tint for seeing objects clearly (brown is best), but blue is fashionable; so the wearer gets the benefit of seeing through a brown tint as well as the benefit of having other people see only the blue mirror coating.
We provide scratch resistant coating on all lenses that we sell at no additional charge. We highly recommend a scratch-resistant coating on any lens you purchase. Before you purchase a lens, check to see if scratch-resistant coating is included, or if it requires an additional fee. Most inexpensive sunglasses do not provide scratch-resistant coating on their sunglass lenses.
Scratch coating does not prevent your lenses from getting scratched. All lenses can scratch because they are made from plastic. Scratch resistant coating is a harder type of plastic that resists scratching, but will scratch when exposed to a harder material.
Tinted lenses have been bathed in tint colors and can assume just about any color shade or color density. The tinted lens actually absorbs the tint color into the lens material. Tint density is defined as a percentage, where 0% is completely clear, and 100% permits no light to pass through (solid). A 10% to 20% tint is used for a fashion tint, and a 50% to 80% tint is used for outdoor protection from the sun.
UV protection filters out the suns ultraviolet rays that are very damaging to the eyes. An extra coating is required for hard resin lenses. However, all polycarbonate, high index, and sun-sensitive lenses already include UV protection due to the characteristics of the lens. Also, according to U.S. Federal Law, all sunglasses sold in the United States must have UV protection.
Unfortunately, many sunglasses sold by street vendors to not comply with Federal Law. Using a tinted lens without UV protection can be extremely dangerous. Lens tint has the effect of increasing the wearers pupil size and admitting more ultraviolet light to the intraocular lens, which can cause premature cataracts and/or permanent damage to your eyes.
For thicker lenses, rolling and polishing the edges of the lenses is very helpful. Rolling removes the sharp edge of the lens after it is cut, and then the edge is polished to make it smooth and shiny. Thicker lenses and lenses in semi-rimless and rimless frames should have edge polish because the edge of the lens is exposed. At eyeglasses.com we include edge polishing automatically for free on all lenses, unless you ask us not to polish the edges.
You can design your own custom prescription sunglasses in the same way that you make your own prescription eyeglasses. Shop for a frame, add a lens with your prescription, and then pick the lens tint and coatings that are best for your needs and lifestyle. Prescription sunglasses are a great way to see in the sunshine. Follow this link to read more about prescription sunglasses.