Whether you're new to glasses, or have been wearing them for years, you can benefit from the newest lens styles and materials. This article will define the varied lens materials, and show you which is best for your individual prescription.
If you’ve needed to buy glasses lately, you’ve probably noticed that there are many more lens material options available than ever before. Should you still wear glass lenses? Do you really need lightweight lenses? Why do lighter lenses cost more? Can you get bifocals in thinner materials?
Whether you’ve been wearing glasses since childhood or are a first-time wearer, this guide will help you understand your options so you can make the best decision for your lifestyle.
The Three Styles of Lenses
Single vision lenses can correct for distance vision or near vision, but not both. The reading glasses sold at drug stores are all single vision lenses and correct only for near.
Bifocal lenses correct for both distance and near vision in the same pair of glasses. Bifocals are available in lined or non-lined styles. Most people over forty years old will need bifocal lenses.
Trifocal lenses have three focal areas divided into lined segments: distance, intermediate, and near. Trifocals are useful for a wide range of visual needs, including computer use.
The good news is that no matter what style of lens your eye care professional recommends, it’s available in a variety of materials to best suit your needs.
The Materials-Lightweight Lenses Defined
Glass-Glass lenses are rapidly becoming outdated. Glass spectacle lenses are significantly thicker and heavier than plastic lenses. Though glass lenses are heat-tempered to further harden them before they are cut to fit your frame, they offer no safety protection. They are difficult to manufacture and replace, causing them to be more expensive than plastic.
Glass lenses also frequently break during the cutting process, which can lengthen the time you’ll have to wait for your glasses to be completed. Glass lenses may be fashion-tinted or treated to darken in the sun while remaining clear indoors. The only benefit to glass lenses is their superior scratch-resistance.
CR-39 Plastic-This is the standard plastic lens available in today’s optical shops. CR-39, commonly referred to as plain old plastic, is a much lighter lens material than glass and is very cost-effective. These lenses are suitable for most prescriptions and can be coated to provide scratch resistance, ultra-violet protection and anti-glare qualities. CR-39 lenses are also available in fashion tints, sunglasses, or treated to darken outdoors. CR-39 lenses are not suitable for safety purposes, children, or people with severely compromised vision.
Polycarbonate-Polycarbonate lenses are a popular choice for a variety of needs. These lenses are thirty percent thinner and lighter than CR-39 and have the added benefit of impact-resistance. All safety lenses certified by OSHA for use in the workplace are made of polycarbonate. These lenses are recommended for athletes, children and those with severely compromised vision to protect their eyes from injury.
Polycarbonate lenses, because of their thinner and lighter qualities, are a good choice for people with moderate to high prescriptions. Anyone with more than three diopters (+3.00 or -3.00 written on the prescription) of visual correction will notice the improvement in comfort over glass or CR-39 lenses.
Lenses made of polycarbonate offer better scratch-resistance than CR-39 and come with built-in ultra-violet protection. They can be tinted for comfort, made into polarized sunglasses, treated to darken outdoors or to reduce glare.
Polycarbonate lenses are not the thinnest lenses available, and they can cause visual distortion at the edges in high prescriptions or those lenses including astigmatism. Even with these drawbacks, these are the best lenses for safety glasses, children, or those who want more protection for their eyes in case of an accident. Many insurance companies and optical retailers discount polycarbonate lenses for children’s spectacles.
Trivex-A relatively new material, trivex lenses are the lightest choice available and come with built-in ultra-violet protection. They are also the best lenses for prescription sunglasses, as they accept the tinting process with the sharpest visual results.
Trivex lenses are impact-resistant, but they are not yet certified for safety eyewear. They are the most versatile lightweight choice for all prescriptions and lifestyles and are suitable for any lens coatings or treatments—especially tinting.
Trivex lenses are sometimes marketed as Phoenix, Eagle Vision or Trilogy lens materials. This is the best lens for people who desire lightweight eyewear. They are also the best lens choice for rimless and drill-mounted eyewear styles as they will not chip or crack at the drilled points.
An added benefit of trivex lenses is that fact that the lens, in single vision prescriptions, is virtually distortion-free, eliminating the need to turn your head to see through the clearest portion of the lens.
Hi-Index-These lenses are by far the thinnest choice available. They are available up to forty percent thinner than CR-39 and are the best suited for high prescriptions. Though hi-index lenses are the thinnest, they are not as lightweight as polycarbonate or trivex. Hi-index lenses come with built-in ultra-violet protection, but are not impact-resistant. They can be coated to reduce glare and increase scratch-resistance, or be tinted for sunglasses.
Hi-index lenses are the most expensive, and usually must be special ordered. They are not suited for children or athletes. Hi-index is recommended for those who are tired of thick, unattractive spectacle lenses and don’t mind the added cost.
The least expensive lens choice is CR-39 plastic. All of the thinner and lighter materials are manufactured using advanced technology and will be more expensive.
The most widely available and least expensive thin, light lens is polycarbonate. This material is stocked in most one-hour shops, boasts excellent scratch-resistance, and has a proven track record of great performance.
If your current spectacle lenses magnify or distort the appearance of your eyes, try lightweight lenses in your next pair. These lenses almost always improve the appearance of your eyewear and minimize the negative effects of a strong prescription.
Lightweight lenses will also improve the comfort of your eyewear. Heavy lenses can cause red indentations on the bridge of the noise or painful pinching behind the ear, often leading to headaches.
Eyewear should be comfortable, attractive and suited to your individual needs. With the many lens choices widely available now, every prescription can be customized to suit the wearer’s needs perfectly.