Lens Technology

    LENS MATERIALS

    Glass:  For generations, eyeglass lenses were made from glass. The majority of optical products were produced of “crown glass”.   While providing superior optics, glass lenses were heavy and easily broken.  Glass makes up a very small portion of the eyeglasses fabricated today.

     

    Plastic:  Plastic eyeglass lenses are fabricated from a plastic polymer called CR-39.  The Armorlite Lens Company is credited with creating the first plastic lenses in the late 1940s.  Plastic is the most popular lens material in use today.

     

    Polycarbonate: A plastic material noted for its impact resistance.  Lenses made of this material are lighter and thinner than regular plastic.  They are recommended for safety lenses, children and those with stronger prescriptions.

     

    High Index: The index of refraction is the measure at which light travels through a particular substance.  “High index” plastics, with their increased refractive index, are the thinnest and lightest lenses available.  Due to their design, stronger prescriptions benefit from using these materials in both appearance and weight.

     

     

    LENS OPTIONS

    Anti-Reflective Coating: The addition of anti-reflective coating has advantages both in seeing and being seen.  This particular lens option is recommended to help eliminate night driving glare, glare from ambient light and backside reflection in sunglass lenses.  Anti-reflective coating will reduce reflections, decrease halos around light, and create a nicer cosmetic appearance. Anti-reflective coating is an important asset to those in public settings such as speaking before and audience or appearing in broadcast media.  The reflection of lights is reduced to a minimum and creates much better “eye contact” with viewers.  AR coatings decrease reflection and produce fewer glares while allowing more light to pass through thus increasing contrast and providing sharper vision. This is particularly noticeable when driving at night or working in front of a computer. Decreased glare means that the wearer often finds that their eyes are less tired at the end of the day.  AR coatings have improved over the last several generations. Premium AR coatings also include a “hydrophobic” surface layer that prevents water spots and makes cleaning easier. Others include an “oleophobic” layer that repels oils and prevents smudging.

     

    Scratch Resistant Coating:  No lens is scratch proof–not even the original glass lenses of the last two hundred years.  It is true that plastic lenses are more susceptible to scratching.   Scratch-resistant coatings can be applied to the front and/or back side surface of lenses to help minimize the appearance of scratches that result from daily use and cleaning.  Often times, the scratches on a plastic lens will be in a circular formation where the wearer has taken a dry towel and rubbed a dirty lens.  The main thing to remember when cleaning lenses is to wash off any thing on them that may be abrasive to the surface.  You wouldn’t wash your dirty car with a dry rag–that would ruin the paint.  The same principle is applied to wiping dirty lenses when they are dry.

     

    Tinted lenses:   Sometimes the addition of a light hint or dark shade of color to your lens can be beneficial to vision. For example, a yellow tint may increase contrast aiding in low light situations.  Hunters often use a yellow tint to help their vision by increasing contrasts.   A light cosmetic tint  can also hide the signs of aging around the eyes.

     

    Mirror coatings: This option is often for strictly cosmetic reasons by allowing the eyes to be hidden from view.  However, those who spend a great deal of time on bright water or snowy slopes also enjoy the addition of a mirror coating.   Mirror coatings come in a variety of colors and styles including full mirror, flash mirror and gradient mirror.

     

    Photochromic Lenses: Photochromic lenses, when exposed to certain conditions, (specifically ultra-violet light), darken in color.  Corning Glass Works is usually credited with the first “changeable lenses”.  From the earliest “Photogray, Photobrown, Photogray Extra and PhotoSun glass lenses to plastic Transitions, there have been, and continue to be, a wide range of photochromic lenses.   Transitions brown, Transitions Vantage, Transitions XTRActive, and Transitions Drivewear.  “Transitions” is a registered trademark name.

    • Transitions® Vantage® lenses do not simply adapt to changing light, they also polarize as they darken. Outdoors, the polarization adjusts to match the level of outdoor glare, which can vary as the day progresses and conditions change. That means you see life in the best light with less glare for better clarity and color.
    • Transitions® XTRActive® lenses adapt to help protect your eyes from fatigue and strain caused by UV light and bright glare outdoors, and even activate behind the windshield. Indoors they have a comfortable faint tint to shield your eyes from strain caused by harsh indoor light.
    • Transitions® Drivewear® combines two of the most advanced technologies in the lens industry: Transitions® photochromic technology and NuPolar® polarization technology. Their Nupolar® polarization removes reflective road, car hood and winshield glare. Transitions® photochromic technology adjusts the color and tint of the lenses as light conditions change, providing ideal color and clarity for driving.

    Transitions® lenses contain special photochromic dyes that cause the lens to activate, or darken, when exposed to ultraviolet rays from sunlight. When the UV light diminishes, the lenses begin to clear. As light conditions change, the level of tint adjusts, offering the right tint at the right time. Regarding ultraviolet light, it’s important to note that the UV radiation blockage remains constant. Transitions® lenses provide automatic protection from UV radiation in both the clear and darkened states.

     

    Ultraviolet Filter:  An important lens addition.  Ultraviolet filter is an inexpensive addition to standard lenses.  It is a colorless, invisible and visually undetectable option to eyeglass lenses that should always be considered.  The effects of ultraviolet light are well known.  Many people routinely take precautions to protect their skin against UV rays: but are unaware of the need to protect their eyes against UV damage. Research indicates that long-term, unprotected exposure to the sunlight can lead to age-related conditions such as macular degeneration, cataracts and other eye conditions that can compromise healthy sight. Most eyecare professionals now recommend that people protect their eyes against UV exposure at all times.  As technology moves forward, some lenses come standard with UV filter.  Tinted lenses offer a degree of protection from some types of ultraviolet rays, but to be 100% safe from both UVA and UVB, always ask for total protection.

     

    Polarized Lenses:  Polarized lenses are the ultimate sunglass lenses.  Nothing eliminates sun glare as does a polarized lens.  In addition, images are clearer and depth perception is improved.  Polarized lenses are available in various colors; however, not all colors are available in all prescriptions and lens styles.  The most popular colors are gray and brown.  Gray is used by those desiring the truest color representation and visual clarity. Brown is used by those desiring greater depth perception and image contrast.

     

     

    Polarized lenses contain millions of parallel rows of tiny iodine crystals or dichroic dyes (so small they can’t be seen with the naked eye) that act in a manner similar to Venetian blinds. Like Venetian blinds, the horizontal rows of iodine crystals contained within the polarized lens block out horizontal polarized light waves, letting  only (non-polarized) vertical light waves reach the eye. This results in comfortable vision with no glare, and is the reason only a polarized lens can block glare. NuPolar is extremely efficient in blocking blinding glare, and improves contrast, color and depth perception and overall visual acuity.  NuPolar lenses define the world standard in prescription sunglass lenses. They feature the most advanced polarizing filters in the widest selection of materials, colors and lens styles.