Lenses & Coatings

Lens Types
 
Single Vision
Single vision lenses are plastic lenses with a single prescription that corrects myopia, hyperopia, or astigmatism. Single vision lenses are uncoated.
Bifocal
Bifocal plastic lenses are correct both for distance and near vision in individuals with presbyopia. In the lower part of the lens, there is a visible semicircle ground into the lens that corrects for near vision. The top of the lens corrects for distance vision.  Bifocal lenses are uncoated.
Trifocal
Trifocal lenses are plastic lenses that correct for vision at three distances. The top of the lens corrects for distance vision. In the lower part of the lens, there is a visible semicircle ground into the lens that corrects for near vision. Just above this semicircle is an additional lens segment that corrects for distances of about an arm's length away. Trifocal lenses are uncoated.
Lenticular
Lenticular lenses are for treatment of eye conditions that are more serious than myopia, hyperopia, presbyopia, or astigmatism. Patients without intraocular implants are often prescribed them after cataract surgery.
● Progressive
Progressive lenses or "no-line bifocals" are bifocal or trifocal lenses that have an invisible corridor of increasing power that leads from the distance portion of the lens down to the reading portion.
 
Materials/Types
 
Plastic: Uncoated lens material.
Polycarbonate: Polycarbonate lenses are made of a material similar to standard plastic, but are lighter in weight and thinner than uncoated plastic lenses. Protection from surface abrasions is offered like in scratch resistant coated plastic lenses, and they do not shatter like glass or standard plastic lenses.
High-index: This is the right choice if one wants thinner and lighter lenses. Thinner, lighter high-index lenses are especially recommended for an individual with strong prescription for nearsightedness, farsightedness or astigmatism.
 
          Thinner. They are able to bend light more efficiently, high-index lenses for nearsightedness have thinner edges than lenses with the same prescription power that are made of conventional plastic material.
 
          Lighter. Less lens material reduces the overall weight of the lenses. Lenses made of high-index plastic are lighter than the same lenses made in conventional plastic, so they're more comfortable to wear. High-index glass lenses also have thinner edges, but high-index glass is heavier than conventional glass, so there is not as much weight savings with glass as there is with plastic lenses. Lightweight lenses are better for farsighted prescriptions, which can make conventional lenses very heavy. The aspheric design gives most high-index lenses a slimmer, more attractive profile and reduces the magnified "bug-eye" look that conventional lenses cause in strong farsighted prescriptions.
High-index plastic lenses are available in a wide variety of refractive indices, typically ranging from 1.53 to 1.74. Lenses with an index of refraction of 1.70 or higher typically are at least 50 percent thinner than conventional plastic lenses.
Transition: Light sensitive plastic lenses are lighter in weight than photochromic glass lenses. They become darker when exposed to ultraviolet light and lighter when removed from the light. Transition lenses resist UV radiation both when light and dark, and the lenses are scratch-resistant.
Glass: Glass lenses are generally heavier than plastic lenses and resist scratching better than uncoated plastic lenses.
Scratch Resistant Coating: Scratch-resistant coated lenses offer protection from most surface abrasions. The coating is available as an option that is applied to the surface of standard plastic lenses after the lenses are ground.
Ultra-Violet Filter: This type lenses reduce transmission of harmful ultra-violet rays from the sun.
Anti-Reflective Coating reduces reflections that cause unwanted glare. Anti-reflective coating can improve vision while driving at night.
Polarized: This type lenses reduce light transmission and reflection from horizontal surfaces, such as snow or water and may improve vision during outdoor activities.
Tint: Tint lenses reduce light transmission.
 

 

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