Good glasses frames are created with good materials. But what kinds of materials can be used, and how do they differ from one another?
In our article, Glasses - Parts, Types and Shapes, we discussed the shapes and components of frames in addition to demonstrating multiple examples of glasses types. In this section, we will dive into the different materials used to give lenses and frames their form and function.
Frames are most commonly made with either plastic materials or metal materials, though other miscellaneous materials also exist. Plastic materials include nylon and propionate, acetates, and carbon fiber, whereas metal materials often consist of stainless steel, monel, and titanium. Wood, aluminum, and precious metals such as gold and silver are less common, but can be found in more expensive and extravagant frames.
Plastic is the most common material modern frames use, as it is generally the most accessible option in terms of affordability and style. The material is lightweight and inexpensive to manufacture, allowing for a wide variety of frame types, shapes, and colors to work with it. Most plastic frames use xylonite, cellulose acetate propionate, or blended nylon, with each type offering different advantages. For instance, cellulose acetate propionate has the special attribute of being hypoallergenic, and blended nylon tends to be highly resistant to hot and cold while remaining flexible (making them perfect for sports frames). Being easier to mold, plastic frames come in the largest number of styles and colors for a more fashionable application.
Nevertheless, the cheaper price of plastic frames does come at the cost of extra durability. Plastic materials are certainly not brittle (the flimsy nature of nylon is what urged manufacturers to begin blending it with polyamides and gliamides in the first place), but they are more likely to fade, break, age, and get scratched compared to other material types.
Metal Frames are typically seen as a higher quality frame material than plastic frames, usually resulting in an elevated price. However, metal frames easily beat out plastic in terms of endurance, sturdiness, and oftentimes even comfort. Common metal materials used include monel, titanium, and beryllium, which makes them heavily resistant to corrosion, daily use, and signs of aging. Monel is often a mixture of many metals and is the most widely utilized metal material in glasses frames. Titanium tends to be colored silver-gray and proves to be lightweight compared to the weight of other metals. Meanwhile, beryllium has excellent anti-tarnishing capabilities, making it great for fishermen or people who spend a lot of time around saltwater.
The drawbacks of metal frames circle back to their higher prices, heavier weight (with the exception of the more pricey titanium), and lack of color and style options. Although they are higher quality, losing or breaking these frames will represent a greater loss than frames made from softer plastic materials, which is why many buyers tend to stick with metal materials for important occasions instead of daily wear. One solution is to opt for a titanium alloy material instead to maintain the majority of titanium’s lightweight benefits at a more reasonable cost. Stainless steel represents another alloy that is easily attainable for most buyers.
In addition to these two categories (plastics and metals), frames can be made with other materials, including wood, silver, gold, and even bone. While these unconventional choices are often expensive and problematic in terms of durability, they can offer a distinctive style that hardly anyone else uses. Frames embedded with crystals and embellished with leather can also be found at high-end optical retailers.
Lenses Material and Technologies
Lenses are not exempt from a range of different possible materials, either. There are three types most lenses utilize: plastic, glass, and polycarbonate.
Similar to frames, plastic is the most common material lenses are created with, adding minimal weight to the frames while accurately bending light to clear your vision. Plastic lenses provide good impact resistance and comfort at a lower cost, making them widely used by many glasses manufacturers. Unfortunately, however, plastic is one of the easiest lens materials to scratch, so be mindful to keep foreign objects and surfaces away from them.
Glass is perhaps the most traditional material used for lenses, harkening back to the invention of spectacles when glass was the primary option. Advantages of glass lenses include a higher resistance to scratching, the ability to be created with thinner materials, and offering clearer vision than plastic lenses. But be careful: glass is also more prone to cracking due to its low impact resistance, and they will also weigh down the frames considerably compared to other materials.
Polycarbonate Lenses are considered one of the most durable lens types on the market, being extremely resistant to scratches and impacts. Polycarbonate materials are also thinner than standard plastic and boast an even lighter weight, making them perfect for children’s frames, sports glasses, outdoor glasses, and sunglasses. Due to their quality and application, however, polycarbonate lenses can be priced at almost double that of standard plastic lenses.
Different lens technologies are also available to enhance or alter the function of the lenses. For example, lenses with no-vision correction (plano) are usually found in sunglasses, goggles, and specialty eyewear like safety glasses and hunting glasses. Single-vision lenses are used in prescription glasses to correct near, intermediate, or distance vision. Lastly, multi-vision (otherwise known as progressive lenses) can correct both near- and far-sightedness.
Features of high-quality Glasses
Extra features can also be added to glasses in order to achieve better comfort and visual correction during different situations. Here are some examples to consider:
Polarized Lenses offer reduced glare and eyestrain alongside a slight tint (usually 20 to 30 percent) that makes them fantastic for outdoor or water use. Created with a thin film of polyvinyl acetate that is dipped in a conducting solution (such as iodine), polarized lenses utilize a vertical polarized grid of microscopic molecules that disallow horizontal light from passing through, thereby cutting out extra glare.
UV-blocking Lenses are designed with a thin UV (ultraviolet) coating that protects your eyes from harmful UV radiation from the sun. Contrary to popular belief, the tinting of sunglasses does not prevent UV light from entering the eyes, and in many cases makes things worse by allowing the pupils to dilate more. A proper UV protective coating that offers at least UV400 is recommended, as that amount will block all UV light.
Transition Lenses (also known as photochromic lenses) are perfect for people who want a pair of glasses to wear both inside and outside. These lenses use special dyes that darken when exposed to light from the sun and lighten when in the shade. This leads to adaptive lenses that tint themselves in bright light and effectively return to normal in darker conditions.
Scratch-resistant Lenses contain an additional hard coating overtop normal lens materials on both the front and the back. The extra layer helps to prevent large scratches and smudges from forming on the lenses while simultaneously increasing their durability. Coatings such as Crizal are considered high-quality and provide scratch-resistance while reinforcing clear vision.
High Index Lenses are created to be thinner and lighter than standard lenses, using less materials to manufacture and reducing the size of the frame front. These lenses are often preferred by people who have high prescriptions that often result in bulky glasses. Super-thin options of high index materials are also available, providing even less lens material for top-of-the-line comfort at the cost of durability.
Blue-light Blocking Lenses are treated with a special coating that filters down the blue wavelengths of light that are commonly emitted by digital screens and LEDs. Blue-light is usually one of several culprits for digital eye strain, discouraging the eyes from blinking and reigning as some of the most energetic photons the eye absorbs. Cutting down blue light absorption to appropriate levels can help wearers regulate their sleep cycles and keep their eyes refreshed after lengthy screen time.
Anti-reflective Treatment involves applying anti-glare layers to lenses in order to block extra reflections that bounce off the lenses This coating helps to reduce lens reflections in photos and allows other people to notice the wearer’s eyes more easily under bright lights. Anti-reflective benefits are often included with Crizal coatings, though some specialty options intended specifically to reduce reflections are also available.
Anti-smudge Protection is a niche feature for those who are constantly wiping off their lenses with cloths or are annoyed by frequent staining on their glasses. A special coating is applied to a wearer’s lenses that keeps dirt, grease, and other smudge sources from sticking to the material. Anti-smudge protection also provides an added bonus of increasing the durability and easing the maintenance of the lenses.
Progressive Eligible Frames are designed with a wider field of view for an appropriate size to house progressive lenses. Progressive lenses require a suitable amount of surface area to be properly crafted for far, intermediate, and near distance. Frames that are Progressive Eligible are large enough to support the full array of vision correction. Conversely, smaller frames (like the classic John Lennon round glasses) are incapable of utilizing progressive lenses due to their size and shape.