Properties of Polycarbonate Glasses

Polycarbonate lenses are the most shatter-resistant lenses available for eye glasses and are the best choice for safety lenses. Because of the way polycarbonate lenses are made and the way they bend light into the eye, the lenses make things look different and may seem distorted if you are used to glass or plastic lenses.

Polycarbonate Material

• Polycarbonate lenses are made by an injection molding process. Tiny, BB-sized thermoplastic pellets are heated to above 500 degrees Fahrenheit and melted into a liquid, then cooled and molded into lenses. According to a study in the New York Times, polycarbonate is significantly more shatter-resistant than glass or regular plastic lenses.

Vision Side Effects Through Polycarbonate

• Glass, plastic and polycarbonate lenses bend light differently. The way light passes through different materials causes a slight difference in the perception of how you see through each type of lens. Your vision is corrected by light passing through a prescription lens and focusing an image on your retina. Polycarbonate bends light to a greater degree than glass or plastic lenses of equal thickness.
  If you previously wore a glass or plastic lens, there may be an adjustment period needed to adapt to polycarbonate lenses.

Other Side Effects

• Polycarbonate lenses are softer--and hence safer--than other lenses, because they are more apt to bend under pressure rather than break. However, because the lenses are softer than glass or plastic, they can also scratch easier. Scratch-resistant coatings are usually applied to polycarbonate lenses during processing to help make them more durable, similar to a plastic coated lens but not as durable as glass. The coatings are part of the standard price of a polycarbonate lens and make the lens scratch-resistant but no lens is scratch-proof.