Must have Eyeglass Lens Characteristics
by EO Executive Optical | February 24, 2016 at 11:18am

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Eyeglasses frames. This is the first thing we notice when we enter an eyewear store to buy a new pair of glasses. It is a prominent feature of an eyewear that defines a person’s style and personality. We spend a lot of time perusing different colors and design just to pick out the right eyeglasses frame that suits our taste or our lifestyle.

We are too focused on the eyeglasses frame, hence, we forget about the lenses part. The usual scenario is you tell the salespeople your prescription and let them decide for you. Because all lenses look the same, right? They do look the same but the materials lenses are made of do not.

Choosing the right eyeglass lens is a difficult task because you have to consider the type of lens suited for your prescription and what kind of lens treatment you need. You have to select first between glass lens and plastic lens. Although, plastic lens is more prevalent nowadays because it is more durable, unlike glass lens that is breakable or fragile.

If you happen to fancy plastic lenses, the next step is to determine which type of plastic lenses matches your prescription as listed below:

CR-39 lenses

This was invented by Armolite Lens Company in California in 1947 which is made of a plastic polymer and stands for “Columbian Resin 39.” CR-39 is considered a single prescription glasses. It means the lenses have only one function, either for reading or distance. This type of lens weighs half of an ordinary glass lens but both have the same thickness. This is preferred by people with a prescription under +/-3.00 sphere.

Polycarbonate lenses

This is better than CR-39. Polycarbonate (PC) lenses are thinner, lighter and more durable. According to refractivesource.com, it is 10 more times impact-resistant than any lenses. Gentex Corporation, the company who invented the lens in early 1970s, mainly used it for bulletproof glasses. PC lenses are perfect for children, sports enthusiasts, and those who work at hazardous environments such as construction sites. It is recommended for people with prescription above +/-3.00 sphere.

High-index lenses

It is thinner and lighter than PC lenses and works on strongest prescriptions. It is designed for people with myopia, hyperopia, astigmatism and presbyopia. People with 1.60 to 1.74 high index prefers this lens.

High-definition lenses

Eyeglasses can be digitally customized now. According to Vision Service Plan, the technology used to produce high-definition lenses is called “free-form” that uses computer-aided design (CAD) and surfacing. It offers sharper vision and better peripheral vision compared to traditional lenses, consumerreports.org says.

Lens Treatments

Anti-scratch Coating

Scratched eyeglasses may distort vision and can cause eyestrain or headaches. You may prevent this by coating your specs with anti-scratch film. Any type of plastic lenses requires this coating except PC lenses.

Anti-reflective Coating

Glare and reflections are common problems in most eyeglass lenses. This coating could reduce these two and makes the vision sharper. It also makes the eyes appear visible behind the lenses. This is a required feature for polycarbonate and high-index lenses.

UV light Protection Coating

UV (Ultraviolet) light is bad for the eyes. Usually, all glasses have this coating already but do double check if your providers will quote your lenses with it.

Photochromic Coating

This coating automatically darkens the lenses when exposed to the sun and returns to its original colorless state once you’re indoors. You could add this on top of your UV light protection coating.

Blue-light Coating

Too much exposure to LED light released by digital devices such as laptops, smartphones and tablets can damage the retina. It can also cause macular degeneration, eyestrain and cataracts. This coating could remedy that.

Mirror Coating

This coating adds color to the lenses. Don’t worry about the visibility because no matter what color you coat on your lenses it doesn’t obstruct your vision. It acts like a tint of a car window and it also prevents the wearer to be seen by others through the lenses. You could match it with your eyeglasses frame as well.

As always, better ask an ophthalmologist during your eye checkup the right lens type and lens treatment suitable for your condition. Do remember, as pointed out by allaboutvision.com, that “…your eyeglass lenses can easily cost more than the frames you choose – even if you choose the latest designer frames.” This is because of the type of lenses and coating or lens treatment you put on it, so choose wisely.

See? It is not all about eyeglasses frames. Pay attention to your lenses, too.