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How To Choose Lenses For Your Eye Glasses

Glasses lenses: Overview

The type of lenses in your glasses play a huge role in your vision, comfort and safety when wearing eyeglasses. The choice to buy the best lenses for your frames is not an easy task as there are different types of lens materials which come with different features and prices.

When choosing lenses for your glasses whether you are long sighted, shortsighted or you need reading glasses, these are the four factors to look out for:

  • Vision
  • Comfort
  • Appearance
  • Safety

Types Of Lens Materials

  • Glass lenses

In the early days of vision correction, all eyeglass lenses were made of glass. Glass lenses offer exceptional optics. But they are heavy and can break easily, potentially causing a serious eye injury or even loss of an eye. For these reasons, glass lenses are no longer widely used for eyeglasses.

  • Plastic lenses

They are lightweight alternatives to glass lenses and are called CR-39 plastic lenses. Plastic eyeglass lenses are about half the weight of glass lenses. They are relatively inexpensive and have excellent optical qualities. They do not break easily like glasses and therefore will not cause an eye injury.

  • Polycarbonate lenses

The first lightweight polycarbonate lenses for safety glasses were introduced in the 1970s. Since then, polycarbonate lenses have increased in popularity. They are lighter and stronger than regular plastic eyeglass lenses and will hardly break. They are great for children’s eyeglasses, rimless frames, sports glasses and safety glasses. 

  • Trivex lenses

Trivex, a new lightweight and impact-resistant eyeglass lens material, was introduced in 2001. Trivex lenses are a good alternative to polycarbonate lenses. They are lightweight and have better optical properties than polycarbonate lenses but not as light as lightweight as polycarbonate lenses. They are also an excellent choice for children’s eyeglasses, rimless frames, sports glasses and safety glasses.  

  • High-index plastic lenses

In the past 20 years, several different types high-index plastic lenses have been introduced. These lenses are significantly thinner and lighter than regular plastic lenses. They are an excellent choice for very high powered lenses.

Comparing lens materials

Here are popular eyeglass lens materials, arranged in order of refractive index and lens thickness (pretty good indicators of cost). Except for the crown glass, these are all plastic materials.

Lens Material Index Price (Naira) Key Features and Benefits
High-index plastics  1.74 ++++ The thinnest lenses available.

Block 100 percent UV.

Lightweight. The best choice for very high powered lenses

 

High-index plastics

1.67 +++ Block 100 percent UV.

Thin and Lightweight. The best choice for very high powered lenses

Tribrid 1.60 ++ Thin and lightweight.

Significantly more impact-resistant than CR-39 plastic and high-index plastic lenses (except polycarbonate and Trivex).

Higher Abbe value than polycarbonate.

Downside: Not yet available in a wide variety of lens designs.

Polycarbonate 1.59 ++ Superior impact resistance.

Blocks 100 percent UV.

Lighter than high-index plastic lenses.

Trivex 1.53 ++ Superior impact resistance.

Blocks 100 percent UV.

Higher Abbe value than polycarbonate.

Lightest lens material available.

CR-39 plastic 1.50 + Excellent optics.

Low cost.

Downside: thickness.

Crown glass 1.51 + Excellent optics.

Low cost.

Downsides: heavy, breakable, not safe

Eyeglass lens treatments

For the most comfortable, durable and best-looking glasses, the following lens treatments should be considered essential:

 

  • Anti-scratch coating

All lightweight eyeglass lens materials have surfaces that are significantly softer and more prone to scratches and abrasions than glass lenses. Plastic, polycarbonate, Trivex and high-index plastic lenses all require a factory-applied anti-scratch coating for adequate lens durability.

Most of today’s modern anti-scratch coatings (also called scratch coats or hard coats) can make lightweight eyeglass lenses nearly as scratch-resistant as glass lenses. See tips on how to care for your lenses

  • Anti-reflective coating

An anti-reflective (AR) coating makes all eyeglass lenses better. They eliminate reflections in lenses that reduce contrast and clarity, especially at night. They also make your lenses nearly invisible, so you can make better eye contact and you and others are not distracted by reflections in your lenses. AR-coated lenses are also much less likely to have glare spots in photographs.

  • UV-blocking and Harmful Blue Light treatment

Too much exposure to the sun’s harmful ultraviolet (UV) radiation and harmful blue light can harm your eyes. Over time, this can cause age-related eye problems including cataracts and macular degeneration. Here are Six things to consider when buying sunglasses

For this reason, people should protect their eyes from UV beginning in early childhood.

Polycarbonate and nearly all high-index plastic lenses provide 100% UV protection. If you choose CR-39 plastic lenses, these lenses need a special coating applied to block all UV rays and harmful blue light.

  • Photochromic treatment

This treatment enables your glasses lenses to darken automatically when exposed to the sun’s UV rays. The tint then quickly disappears when you go indoors. Photochromic lenses are available in nearly all lens materials and designs.

Cost of eyeglass lenses

Depending on the type of lenses and lens treatments you choose and the lens design you need, your eyeglass lenses can easily cost more than the frames you choose — even if you choose the latest designer frames.

So, how much will your glasses cost? That’s hard to say.

The amount you pay for your next pair of glasses will depend on many factors, including your visual needs, your fashion desires and whether you have vision insurance that covers a portion of the cost of your eyewear.

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