Lens Types

• Single Vision
  Single vision lenses are uncoated, plastic lenses with a single prescription that corrects myopia, hyperopia, or astigmatism.
• Bifocal
  Bifocal lenses are uncoated, plastic lenses that correct both for distance and near vision in individuals with presbyopia. 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.
• Trifocal
  Trifocal lenses are uncoated, 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.
• Lenticular
  Lenticular lenses are designed to treat eye conditions that are more serious than simply myopia, hyperopia, presbyopia, or astigmatism. They are often prescribed after cataract surgery for patients without intraocular implants.
• Progressive
  Commonly called "no-line bifocals", progressive lenses 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: Common 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. They offer protection from surface abrasions like scratch resistant coated plastic lenses, and they do not shatter like glass or standard plastic lenses.
• High-index: High-indesx lenses are 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. Because of their ability 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. Thinner edges require less lens material, which 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 even more of a benefit for farsighted prescriptions, which can make conventional lenses very heavy. And most high-index lenses also have an aspheric design, which gives them 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: Transition lenses are light sensitive plastic lenses, which makes them lighter in weight than photochromic glass lenses. They become darker when exposed to ultraviolet light and lighten 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 included as a part of polycarbonate lenses, but is also available as an option that is applied to the surface of standard plastic lenses after the lenses are ground.
• Ultra-Violet Filter: Reduces transmission of harmful ultra-violet rays from the sun.
• Anti-Reflective Coating: Increases light transmission through the lens by reducing reflections that cause unwanted glare. Anti-reflective coating can improve vision while driving at night.
• Polarized: Polarized lenses reduce light transmission and reflection from horizontal surfaces, such as snow or water and may improve vision during outdoor activities.
• Tint: Tinted lenses reduce light transmission.