 Spectacle Lenses
LENS COATING/TINTS
HOW TO CARE FOR YOUR SPECTACLES
TYPES OF LENSES
Single Vision Lenses
Single vision lenses are used to correct for myopia, hyperopia and astigmatism, they have the same power throughout the whole lens, and correct the vision at one distance, whether it is for distance, near, or intermediate (i.e.: computer screen distance) vision. They come in all types of materials: plastic, polycarbonate, glass photochromic and Trivex. and can have any coating or tint that you require applied.
Bifocal lenses
Bifocals are needed to correct for presbyopia. The lens is split into two sections. The upper most part is used for seeing in the distance and the lower part is for near vision.
They are usually prescribed for people over the age of 40 whose focusing ability has declined due to presbyopia. The segment for near vision correction can be shaped like a half moon, also called a flat top or a straight top, or like a round segment. They come in all types of materials: plastic, glass, polycarbonate and Trivex.
Trifocal lenses
Similar to bifocals are trifocals, or lenses with three points of focus-usually for distance, intermediate and near. Trifocals have an added segment above the bifocal for viewing things in the intermediate zone, which is farther away than the near zone or about arms length away. Computer screens are an excellent example of something that is in a person's intermediate zone. Flat top lens styles are the most commonly used trifocals. They come in plastic and glass materials.
Progressives Lenses
Progressive lenses, sometimes referred to as no line bifocals or invisible bifocals, not only provide visual correction for the distances that traditional bifocals can't, but they also hide the fact that you are even wearing bifocal lenses because there is no visible line on the lens. They provide a smooth transition from distance, through intermediate, to near with all the in between corrections included as well.
Progressive lenses tend to give the most natural vision correction compared to bifocals or trifocals. There is usually a short adaptation period when you are first fitted with your progressive lenses, where you need to get used to using the progressive lenses, this adaption can range from a few hours to a few weeks depending on the individual.
Nowadays progressive lenses can be fit into shallower, smaller, more fashionable frames by using progressive lenses designs that are more compact. Progressive lenses come in all types of materials: plastic, glass and Trivex and can have any of the available tints or coatings applied.
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