Lens coatings




Anti-reflectiveedit

Anti-reflective coatings help to make the eye behind the lens more visible. They also help lessen back reflections of the white of the eye as well as bright objects behind the eyeglasses wearer (e.g. windows, lamps). Such reduction of back reflections increases the apparent contrast of surroundings. At night, anti-reflective coatings help to reduce headlight glare from oncoming cars, street lamps and heavily lit or neon signs.

One problem with anti-reflective coatings is that historically they have been very easy to scratch. Newer coatings try to address this problem by combining scratch resistance with the anti-reflective coating. They also offer a measure of dirt and smudge resistance, due to their hydrophobic qualities.citation needed

Ultraviolet protectionedit

A UV coating is used to reduce the transmission of light in the ultraviolet spectrum. UV-B radiation increases the likelihood of cataracts, while long-term exposure to UV-A radiation can damage the retina. DNA damage from UV light is cumulative and irreversible. Some materials such as Trivex and Polycarbonate, naturally block most UV light; they have UV-cutoff wavelengths just outside the visible range, and do not benefit from the application of a UV coating.citation needed Many modern anti-reflective coatings also block UV.

Scratch resistanceedit

Resists damage to lens surfaces from minor scratches.

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