Corrective lenses have come a long way from when they were first invented, and we aren’t just talking about what they can do for different types of vision problems, but what they’re actually made of.
60 AD: One legendary example of a vision-correcting lens being used in antiquity was by Emperor Nero of Rome, who used an emerald to better see gladiator fights. However, it’s possible that this was only for protection against the sun.
10th Century: The first definite example we have of manufactured lenses for aid in reading came in medieval Europe, where monks would use “reading stones,” or polished domes made of transparent quartz to magnify text. Two and a half centuries later, these reading stones would be fashioned into the first spectacles in Italy.
14th Century: For some time, glasses were such a status symbol that they were only made of the most expensive materials. Gradually, the preferred lens material shifted from crystal to glass. Following the invention of the printing press in 1440, literacy rates skyrocketed and so did the demand for affordable glasses.
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While we make most modern lenses out of different types of plastic, we still use glass lenses even after all these centuries. The advantages of glass lenses are that they’re highly scratch-resistant and affordable, with minimal chromatic aberration (optical distortion of colors). However, their weight makes them impractical for strong prescriptions, and they break easily.
Plastic lenses range from standard to high-index. These lenses are lightweight, impact resistant, and can be much slimmer than glass, depending on how high-index they are (although that does impact the price).
Polycarbonate lenses are ideal for children and athletes because they are virtually unbreakable. They’re also great for strong prescriptions because they don’t add thickness and are very light. They aren’t very scratch-resistant, but special coatings will take care of that. Speaking of which…
A particularly valuable modern glasses innovation is the variety of coatings that we can apply to the lenses. Softer lens materials benefit from scratch-resistant coatings. You can also get lenses with a UV-protective coating to block harmful UV radiation from reaching your eyes. Another coating that is particularly important in the modern age of digital screens is an anti-reflective coating that eliminates glare and reduces digital eye strain.
If you’re not sure which lenses you should get in your next pair of glasses or if you have questions about any of these lens types or coatings, we can help you pick the perfect lenses at your next eye exam!