Many people still assume eyeglass lenses are made from glass. The reality is most lenses are now made from various forms of plastic. Glass is still available but is becoming increasingly rare due to its weight and potential to shatter. Unless there is a specific need, the overwhelming majority of patients are very happy in a lighter weight material. There are many differences between lens materials.
This material is the most basic lens material. When an insurance company says they “cover” a lens, this is the material typically covered. This lens material is not shatter resistant or UV protected. Because of this, we at Best Eyecare Associates will never recommend this lens material for daily wear. We would much rather see our patients’ eyes be protected in case of an accident.
Polycarbonate lenses have been one of the most sold materials in the industry since it was introduced in the 1980s. This material is UV protected and shatter resistant. It is often a “covered” benefit for children because of its shatter-resistant properties. The downside of this material is that it is the least optically clear lens, meaning the brain must tune out distortion caused by the material itself. Some patients are not able to tune out that distortion and they cannot wear the polycarbonate material at all. This distortion issue is why we at Best Eyecare Associates will typically recommend an alternate material so that our patients have the best visual experience out of their lenses.
The newest material on the market, the trivex material was specifically developed to solve the distortion issues of polycarbonate without losing the safety. Trivex is shatter resistant and UV protected and the optical quality is significantly better than polycarbonate. Patients who could not wear polycarbonate are comfortable wearing trivex. Even patients who are not sensitive to polycarbonate find the trivex preferable.
The index of the lens describes the materials ability to refract light. The higher the index the less material required to create the patient’s prescription. This generally means a thinner and possibly lighter lens. Most patients with high prescriptions prefer the hi-index lenses but there are some reasons a patient might not. The high index lens is not shatter-resistant. For children with high prescriptions in particular, the benefits of the thinner lens must be weighed against the loss of the shatter-resistant properties. Also, some patients may experience visual distortion because of the way light travels through the lens. Often the visual disturbances of the material can be reduced with the use of a quality anti-reflectant coating. Our opticians will discuss the pros and cons of each lens option when helping you choose what material is right for you.
Lens Coatings and Treatments
There are many options to customize and optimize your vision. Here at Best Eyecare Associates, we try to guide patients through those options to help meet their needs and maximize the visual quality of their lenses.
Anti-reflective coatings reduce the glare on your lenses. Glare is fatiguing to the eyes and can make driving at night more difficult. The anti-reflective coating can help your eyes from becoming as tired during the day and will reduce the haloing of oncoming lights when driving at night. Anti-reflective coatings will also make your lenses more clear so when people are looking at you they can more easily see your eyes and not a white reflection on your lenses. Most people don’t realize that the lenses the optometrist uses to determine your prescription have an anti-reflective coating, same for the lenses in your camera, the screen of your smartphone and the lenses inside the Hubble telescope.
There are different levels of quality in anti-reflective coatings. The differences are in the coating’s durability, clean-ability, scratch resistance, and warranty. At Best Eyecare Associates we recommend the highest quality anti-reflective coatings because they provide the clearest vision for our patients and the best warranties, up to 2 years with no additional fees for remakes.
Sun Reactive Lenses
Sun reactive lenses are lenses that turn dark when exposed to UV rays. People know them by the name Transitions, which is the most well know brand of light reactive lenses. These lenses will darken outside and then return to clear when indoors. There are multiple colors, different intensities of darkness, even some that will become polarized or have a mirrored effect when dark. These lenses do not typically achieve full darkness when behind the windshield of a car so are not considered a replacement for sunglasses but they can be an excellent option for someone who is light sensitive or for whom switching between clear glasses and sunglasses is too cumbersome.
Tinted vs Polarized Lenses
When a patient wants a pair of sunglasses the first question our opticians will ask is, tinted or polarized? The patient will typically then ask, what’s the difference?
A tint is a when the lens is darkened in a tint bath. It can be done in many different colors and made to different levels of darkness. A tint can be a solid uniform darkness through the entire lens or gradient from dark to light.
Polarization is a lamination process that cuts the suns reflective glare about 30% making for a better visual experience in bright sun. It is considered a safer lens for driving since it can increase visibility in high glare situations. It is typically offered in grey, brown or grey-green colors, though it may be available in limited other colors.
BluTech Tinted Lenses
The effect of blue light is a topic of much research and development in the optical world. The blue light that comes from our many devices is proving to be troublesome to our comfort and perhaps our health. In order to mitigate some of the negative effects of this blue light, BluTech lenses were developed. These are not a standard tinted lens. BluTech is a melanin injection into the lens material that filters approximately 40% of that blue light. This makes working on the computer much more comfortable and less tiring. Patients who have used the BluTech say they feel less tired at the end of a long day on the computer and regularly recommend the lens to their coworkers.