HOW TO CHOOSE THE BEST LENSES FOR YOUR GLASSES

The lenses you choose for your eyeglasses — even more than frames — often will determine how happy you are with your eyewear.

And buying eyeglass lenses is not an easy task. In fact, there are so many choices for lenses and coatings, that it's easy to be confused about all the choices.

 

This buying guide will help you cut through the hype about different types of eyeglass lenses and help you choose lenses and coatings that offer the best features and value for your needs.

 

Why Choosing The Right Eyeglass Lenses Is So Important

 

When buying eyeglasses, the frame you choose is important to both your appearance and your comfort when wearing glasses. But the eyeglass lenses you choose influence four factors: vision, appearance, comfort and safety.

Eyeglass lens thickness is determined in part by the size and style of the frame you choose. For thinner lenses, choose smaller, round or oval frames. Also, plastic frames hide edge thickness better.

A common mistake people often make when buying eyeglasses is not spending enough time considering their choices of eyeglass lens materials, designs and coatings.

 

Plastic lenses:

 

In 1947, the Armorlite Lens Company in California introduced the first lightweight plastic eyeglass lenses. The lenses were made of a plastic polymer called CR-39(index=1.498), an abbreviation for "Columbia Resin 39," because it was the 39th formulation of a thermal-cured plastic developed by PPG Industries in the early 1940s.

Because of its light weight (about half the weight of glass), low cost and excellent optical qualities, CR-39 plastic remains a popular material for eyeglass lenses even today.

 

Polycarbonate lenses:

 

In the early 1970s, Gentex Corporation introduced the first polycarbonate lenses(index=1.586) for safety glasses. Later that decade and in the 1980s, polycarbonate lenses became increasingly popular and remain so today.

Originally developed for helmet visors for the Air Force, for "bulletproof glass" for banks and other safety applications, polycarbonate is lighter and significantly more impact-resistant than CR-39 plastic, making it a preferred material for children's eyewear, safety glasses and sportswear.

 

Trivex lenses:

 

A newer lightweight eyeglass lens material with similar impact-resistant properties as polycarbonate is called Trivex(index=1.54), which was introduced for eyewear in 2001. Trivex® material was developed to produce a unique combination of patient benefits: lightweight, improved protection, thin, superior clarity of vision and full UVA/UVB protection compared with older lens technologies.

 

High-index plastic lenses:

 

In the past 20 years, in response to the demand for thinner, lighter eyeglasses, a number of lens manufacturers have introduced high index plastic lenses(index=1.6 to 1.74). These lenses are thinner and lighter than CR-39 plastic lenses because they have a higher index of refraction (see below).Because high index lenses can form prescriptions using less physical material, they provide lenses that are both lighter and thinner than identical lenses formed out of standard glass or plastic. If you have a very slight corrective prescription, you might not enjoy much of a boost here; however, the stronger your prescription gets, the more benefit you’ll receive. A lens that would be extremely thick and heavy if made of standard material can be considerably thinner and lighter if formed of high index material.

 

Index Of Refraction:

 

The higher the refractive index of a material, the slower light moves through it, which results in greater bending (refracting) of the light rays. So the higher the refractive index of a lens material, the less lens material is required to bend light to the same degree as a lens with a lower refractive index.

In other words, for a given eyeglass lens power, a lens made of a material with a high refractive index will be thinner than a lens made of a material with a lower refractive index.

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Popular types of lenses

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Single vision lenses

Single vision lenses have one single prescription across their entire surface and are suitable in all scenarios, whether you need your glasses for driving, working or reading.

If you need to wear glasses for both distance and near vision, you could wear separate pairs of single vision glasses dedicated to each task. However, the preferable option would be to consider the benefits of bifocals or progressive lenses.

 

Bifocal lenses

A bifocal lens provides distance and near vision in one lens. The near vision correction of the lens is contained in a segment, often visible on the front of the lens. This segment provides the extra power necessary for you to read clearly.

Bifocals may still leave a gap for mid-distance vision; and, as a line dividing the lens is visible, some customers feel bifocals are not as cosmetically appealing.

 

Progressive lenses

Progressive lenses are recommended for the convenience of having natural vision at all distances in one pair of glasses. Progressive lenses have a great cosmetic appearance with no visible line on the lens, unlike bifocal lenses. Our range of progressive lenses ranges from our entry-level lenses to our more popular range with advanced optimised lens design to improve the fields of vision with minimal soft focus(areas of less than 100% clear focus).

 

 

Lens enhancements

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Scratch Resisting Coating

 

Scratch-resistant lenses provide protection from everyday accidental damage. The hard coating prolongs the life of the lens, whilst simultaneously providing clearer vision. 

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Anti-Reflective Coating

 

Removes reflections for clearer vision and great appearance.

The curved surface of glasses lenses, along with the materials they are made from, cause reflections. In fact, you can lose around 10% of light through reflections on lenses. These reflections can be distracting and appear unattractive.

An anti-reflective coating allows for clearer vision by reducing reflections, allowing 99.8% of the light through the lens and ensuring distractions to your vision are minimal. Your glasses' appearance is also improved, as others can see your eyes rather than reflections of light.

 

 

High Refractive Index Lenses

 

Thinner for improved appearance, lighter for more comfort.

We recommend High Refractive Index lenses to give you the best looking and most comfortable glasses possible.

Lenses can be made of various materials of varying weight and thickness – the overall result depends on the density of the lens material as well as your personal prescription. As a general rule, if you are long sighted your lenses are thickest in the middle, and the opposite is true if you are short-sighted (the lenses are thickest at the edges).

High Refractive lenses reduce the overall thickness of your lenses, giving them a lighter feel and improving appearance. 

 

 

UV-Blocking Treatment

 

Cumulative exposure to the sun's harmful ultraviolet radiation over a person's lifetime has been associated with age-related eye problems including cataracts and macular degeneration.

For this reason, people should protect their eyes from UV beginning in early childhood. Thankfully, polycarbonate and nearly all high-index plastic lenses have 100 percent UV protection built-in, due to absorptive characteristics of the lens material.

But if you choose CR-39 plastic lenses, be aware that these lenses need an added coating applied to provide equal UV protection afforded by other lens materials.

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Photochromatic Lenses

 

This lens treatment enables eyeglass lenses to darken automatically in response to the sun's UV and high-energy visible light rays, and then quickly return to clear (or nearly clear) when indoors. Photochromic lenses are available in virtually all lens materials and designs and is more popularly known as Transitions.

 

Protecting Your Eyes From Digital Blue Light

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Digital devices fit so naturally into our daily lives that it's easy to forget how "unnatural" it is for our eyes to work, read and play from a digital display for hours. Backlit displays expose us to higher than normal amounts of blue light which can cause digital eye strain, fatigue and sometimes permanent damage to your eyesight. Ask about our Choice BluSelect lens option to block 100% of UV light and filter HEV blue light to protect your eyes from the harmful effects of the blue-violet light spectrum.