Everyone from designers to stylist to patients themselves recognizes eye wear as a fashion accessory. An eyeglass frame is first and foremost to hold the lenses you need to see. If you have a mild to moderate prescription there is a huge choice of styling available. The stronger the prescription the more one needs to consider how the prescriptions impacts the final look. Below are a few of the frame brands that we carry.
Glass Lenses
Glass is the hardest lens material and offers the best protection against scratches. But glass lenses can shatter more easily than plastic lenses, are twice as heavy as plastic lenses, and don’t provide as much protection from the sun’s harmful ultraviolet (UV) rays. Unless your main concern is scratch protection (and you don’t mind wearing heavy glasses that might slide down your nose frequently) heavy, your better choice in a lens material for your eyeglasses is anything but glass.
CR-39 Plastic
For many years, CR-39 plastic has been the standard lens material for eyeglasses. (The “CR-39” is the name given to the resin formulation by the original manufacturer.) CR-39 plastic lenses are half the weight of glass lenses, have better ultraviolet (UV) light protection, are less prone to shattering, and can be tinted more easily. And with an added scratch-resistant coating, they are nearly as resistant to scratches as glass lenses. CR-39 plastic lenses are about the same thickness as glass lenses.
Polycarbonate Lenses
Polycarbonate lenses are made of a type of plastic that is more impact-resistant than standard plastic lenses. Polycarbonate lenses are also much thinner and lighter in weight. Polycarbonate lenses also have built-in ultraviolet protection. Because of these properties, it has been the lens material of choice for children’s lenses, sport lenses and safety lenses. However, some people complain that polycarbonate lenses fail to give them the crispest, clearest vision.
Trivex Lenses
Trivex is a new material that is similar to polycarbonate lenses but with higher quality optics, and thus provides clearer vision. Trivex is lighter in weight than standard plastic and is about the same thickness as polycarbonate. Trivex is a more rigid material, making it a better selection for rimless or drill mount frames. Trivex is just as impact resistant as polycarbonate and may also be prescribed for children’s lenses, sport lenses and safety lenses. Trivex is also more tintable compared to a Polycarbonate lens. Trivex has 100% UV protection.
Refer to www.hoyavision.com for more information about HOYA’s Trivex lens called the Phoenix.
Hi-Index Lenses
Hi-index lenses are made of a special plastic material that refracts light in a different way than regular plastic lenses. With hi-index lenses, vision can be corrected with less material, making the lens much thinner. Plastics are graded in numbers, such as 1.50 or 1.67. The higher the number, the thinner the lens. Because they are thinner, hi-index lenses are also lighter, making them more comfortable to wear. This is important to patients with high prescriptions, as their glasses can be made more cosmetically attractive and appealing.
Anti-reflective Coatings
Anti-reflective coating is applied to eyeglass lenses to reduce the amount of internal and external reflections on a lens. This increases the amount of light transmitted through the lens, which improves quality of vision. Anti-reflective coating also decreases unwanted glare and halos at nighttime. It also makes the lenses appear somewhat invisible and very thin. While everyone could benefit from an anti-reflective coating, it is especially beneficial for people with high prescriptions, people who have a decrease in vision at night, and professions in which cosmetic appearance is important.
Scratch-Resistant Coatings
Scratch-resistant coatings are applied to the front and back of lenses in the manufacturing process. Although it is important to realize that no lens is scratch-proof, this special coating does make lenses harder to scratch when dropped or rubbed against a hard surface.
Ultraviolet Treatments
Ultraviolet treatment is applied to lenses to protect against harmful UV sunrays that can accelerate the development of cataracts and macular degeneration. It is extremely important to protect eyes from the damaging effects of the sun. UV treatment is easy to apply to lenses and is often included with the purchase of eyeglasses.
Polarized Lenses
Polarized lenses are usually used to make sunglasses. They are available most commonly in grey or brown tint but many other colors are available. Vertically polarized lenses decrease bright glare and reflections by blocking horizontal polarized reflected light. Polarized lenses have been used by fishermen for years to better deal with bright light being reflected off water and to see deeper into the water.
Photochromatic Lenses (Transitions)
Photochromatic lenses have a special chemical coating that makes them change to a dark tint in the sunlight and turn clear indoors. Photochromatic lenses are great for people who do not wish to carry a separate pair of prescription sunglasses and an excellent option for children. It is important to recognize that these lenses do not darken as well while driving a car. The windshield prevents most of the UV light from reaching the lens.
Check out www.transitions.com for more information on the different types of Transitions lenses.