Lenses & Coatings
Contact
Anti-Reflective Coating
Normal lenses often create glare, reflections, and "ghost images." Now that can be eliminated with an anti-reflective coating.
What we see is a result of light being sensed by our eyes. With normal glasses, much of the light reflects off the lenses. This produces glare. It also reduces the wearer's visual acuity. In other words, the light reflections are a cosmetic and visual problem.
Anti-reflective coatings increase light transmission through the lenses to 99.5 percent. It makes it easier to see and easier for others to see you. These coatings are especially useful for those viewing computer screens and driving at night.
Bifocal Lenses
For many people, different lenses are needed for seeing at different distances. Bifocal lenses allow the wearer to look through two areas of the lens. One area focuses on distant objects. The other is used for reading. A little-known fact is that bifocals were invented by Benjamin Franklin, and his style of bifocals are still available today.
Most of the time the "reading" area is smaller, shaped like a sideways 'D', and found in the lower half of the lens. These bifocals are called lined bifocals or flat-tops. If you are focusing on distant objects, you look through the top half of the lenses. To read a book, magazine, or newspaper, you look through the lower "reading" area. The Franklin style lenses are less common, and are split horizontally down the middle of each lens. One thing that is difficult about using bifocals is dealing with the line between the two vision areas. Fortunately, recent technologies have come up with a new type of lens, called the no-line, or progressive lens.
High Index Lenses
Prior to the last few years, the only materials available to use for lenses were glass and a hard resin called CR-39. But recently, high index lenses have become available. High index materials are named because they have a higher index of light refraction. Basically, they can do the same job that glass or CR-39 does, but high index lenses are thinner and lighter. With high index lenses, you can avoid having "soda bottle" lenses.
When speaking about high index lenses, you may hear many unfamiliar numbers and terms. Here are a few things to remember.
- Polycarbonate
The first and still most popular high index plastic is polycarbonate. Polycarbonate was originally developed for fighter jet cockpits. It is very strong, very light, and resistant to scratches and impact. Most sports lenses are made of polycarbonate. - Mid-Index
Other high index materials are classified by numbers. The higher the number, the thinner and lighter the lens. The lower numbers are classified as mid-index lenses. Mid-index lenses, such as 1.54, 1.56, and 1.57. These lenses are thinner than glass, and nearly as strong as CR-39. - High-Index
High index lenses, such as 1.66, 1.74, and 1.9, are much thinner than glass, but not as strong. Talk with one of the doctors when deciding which high index lens is right for you.
Progressive Lenses
One of the main problems with bifocal and trifocal lenses is the problem of eye fatigue. It is difficult to switch from one focusing power to another. It can make your eyes tired, and it can even lead to a headache, sore neck and sore back.
A recent variation of bifocals and trifocals are multi-focal lenses, often called no-line lenses or progressive lenses. No-lines provide a smooth transition from focusing on nearby to focusing on distant objects because they do not have a distinct line which separates the focusing powers. Instead, a gradual change in power allows the wearer to focus on objects at all distances. Distant objects are viewed through the upper portion of the lens, while near objects are viewed through the middle lower portion of the lens.
Polarized Lenses
Glare from wet roads, light reflecting off other vehicles, and glare from your own windshield can be annoying and dangerous. To eliminate this glare, you may want to get some polarized lenses. Polarized lenses eliminate almost all glare, reducing eye strain and increasing visibility. Polarized lenses are the most effective way to reduce glare.
Most glare comes from horizontal surfaces, so the light is "horizontally polarized." Polarized lenses feature vertically-oriented "polarizers." These polarizers block the horizontally-polarized light. The result is a glare-reduced view of the world. Polarized lenses can make a world of difference for any outdoor enthusiast. Fisherman can eliminate the bright reflections from the water and actually see into the water more easily than with any other sunglasses, golfers can see the green easier, and joggers and bikers can enjoy reduced glare from the road. In addition, drivers can enjoy the safety and comfort that polarized lenses provide while driving.
Scratch Resistant Coating
If you have hard resin lenses (CR-39 or high index lenses), you should consider getting a scratch resistant coating. Resins and plastics are more susceptible to scratches than glass. Scratches damage the cosmetic look of the lenses as well as their performance. With a scratch resistant coating, you don't have to worry so much about minor scratches on your lenses.
Another advantage of scratch resistant coatings is that most coatings come with a one-year warranty. They are a great investment to prevent minor scratches. However, it is important to remember that scratch resistant does not mean scratch-proof. All lenses are susceptible to scratches.
Specialty Lenses
We all have heard the phrase, "Different strokes for different folks." Well, this holds true in terms of selecting glasses. There are different lenses for just about anybody. No matter what your particular need, there's probably a specialty lens designed for you.
For example, a specialty lens that is becoming increasingly useful is designed for computer users. Computer lenses have "windows" designed for viewing your computer screen, documents on your desk, and distant objects. The lenses are designed to reduce Computer Vision Syndrome, or CVS, which is characterized by headaches, eye strain, neck and back aches, dry eyes, blurred vision, and double vision.
Another example is called the double D-segment lens, also known as the double flat-top lens. If you look through most of the lens, you can focus on distant objects. But you can also look through a D-shaped segment near the top of the lens to see nearby overhead objects more clearly. This is very useful if you are involved in work where you're looking at nearby objects above your field of vision. The D-shaped segment near the bottom of the lens allows for reading.
Trifocal Lenses
Bifocals allow the wearer to read through one area of the lens, and to focus on distant objects through another area of the lens. As the eyes age, though, a stronger prescription is needed to read. This would be fine, but the stronger prescription that allows for reading makes it difficult to focus on objects at intermediate distances, such as grocery items on a shelf or your speedometer. Thus, trifocals are necessary for a third prescription for intermediate focusing.
Trifocals, also known as line trifocals, feature three areas of focusing power, each separated from the other by a distinct line. The three windows allow for focusing on distant objects, intermediately distanced objects, and for reading. The downside of trifocals is dealing with the lines between the different focusing powers. Fortunately, recent advances in technology have led to developments in no-line, or progressive lenses.