Eyeglass Lenses: Glass for Glasses?

Although we still refer to our lenses as "glasses", actual glass lenses for prescription eyewear are far less common in the modern age. Some high-end fashion sunglasses, such as Persol, Garrett Leight, and Ray-Ban, are still equipped with real glass sun lenses. The industry standard for hundreds of years was glass because of its extraordinary durability and clarity. Glass lenses scratch less easily than plastics due to their rigidity. Glass lenses can, to a very small degree, be buffed or polished to help reduce the visibility of deep scratches on the lens surface. Glass lenses can also have a low index of refraction, which allows for greater color fidelity and sharpness compared to some plastics.
 

So, if glass is so great, why change? One reason is that glass is heavy. Glass is rigid and nice to look through, but significantly heavier than most modern lens plastics. This is partially why many antiquated eyewear styles are small and round. A smaller glass lens can be less heavy while still allowing for prescription curves on the front and back side of the lens. However, this can be limiting style-wise and for higher prescription needs. Glass can also shatter, causing the heavy and sharp pieces of the lens material to become a safety hazard. In my time as an optician, I'm embarrassed to admit that I've shattered glass lenses on the way in or out of an eyeglass frame. The end result was typically a dustpan and band-aids for my fingers.
 

The last thing I'll mention about glass lenses is that they are expensive to produce. This is because each prescription and frame need is custom to the wearer, meaning that prescription glass eyewear is a more labor-intensive process. Plastic lenses can be pre-fabricated and mass-produced to limit cost and the need for a "start from scratch" approach to each pair of eyeglasses. Glass lenses are also more likely to break during production. This means that opticians who work with glass lenses need to be highly trained in order to be trusted with the production risks.

Modern Plastic Eyeglass Lenses

Luckily, the accessibility of plastics in the modern age makes plastic lenses far less expensive to produce. There are hundreds of manufacturers of plastic lenses, and more than a few types of machines that process them into your prescription. Mid-index plastics can emulate the refractive clarity of glass while maintaining durability. High-index plastics are far lighter than their glass predecessors. From basic to advanced, plastic lenses have the capacity for blended progressive lens designs as well. For more in-depth info, come by the store or give us a call. Our team is dedicated to helping you make an informed decision about your eyewear.