Is CR-39 scratch resistant?
Developed by PPG during WWII, CR-39, also known as plastic or hard resin, serves as a much lighter lens material (approximately 50% lighter) than glass. CR-39, however, is far less scratch resistant and often must be coated to improve its scratch resistant characteristics.
Is it worth getting scratch resistant coating?
Without bothersome reflections, more light is able to pass through your lenses which optimizes your vision. Fewer distractions are visible (especially in the dark), and the lenses are hardly noticeable. Most people agree that anti-reflective coatings on their glasses are definitely worth the added cost.
Is CR-39 or polycarbonate more scratch resistant?
A disadvantage of polycarbonate is that it is naturally a soft material causing it to scratch much easier. However, unlike CR-39 basic plastic lenses, a scratch resistant coating is almost always standard as it is applied when the lenses are made.
What lens material is most scratch resistant?
Glass. Glass offers superior optics and is the most scratch-resistant material available. However, glass must be specially treated for impact resistance. Glass is also much heavier in weight and not offered in many designs.
Which is better CR-39 or polycarbonate?
In comparison to polycarbonate, CR-39 provides vastly superior optics, rating just one rung below the material with the highest ABBE value: crown glass. On the flip side, CR-39 is the thickest and heaviest lens material.
Is CR-39 A polycarbonate?
An alternative material to polycarbonate is CR39 (Columbia Resin 39), a plastic polymer commonly used in the manufacture of eyeglass lenses. Unlike polycarbonate, CR39 requires a UV coating to be added to protect eyes from the sun’s harmful rays.
Does CR-39 block UV?
Conclusions: These data suggest that UV tinted CR-39 lenses provide protection against UV radiation that meets the ANSI Z80. 3-1996 Standard for non-prescription sunglasses and fashion eyewear.
How long does scratch resistant coating last?
about two years
One lens coating that can increase the life of your lenses is scratch resistant coatings. Use these if you tend to handle your glasses roughly or use them in rough environments. According to Dr. Moos, lens enhancements and coatings can last anywhere from a year to about two years.
Do CR-39 lenses have UV protection?
Is CR-39 a glass?
Meet CR-39 Half as heavy as glass, far less likely to shatter, and optical quality nearly as good as glass. CR-39 is heated and poured into optical quality glass moulds – adapting the qualities of glass very closely.
Is high index better than polycarbonate?
Polycarbonate is by far the safest lens available. It’s up to 10X more impact-resistant than high-index lenses and is therefore the ideal lens material for sports protective eyewear and children’s glasses. Polycarbonate is the standard choice for almost all eyewear that requires shatter and/or chip resistance.
Is CR-39 impact resistant?
A CR-39 lens is quite impact resistant. If you live a regular lifestyle, or wear your glasses just for the regular lifestyle aspects, being concerned about a shattering lens might be overblown.
What is the difference between CR-39 and scratch resistant lenses?
However, unlike CR-39 basic plastic lenses, a scratch resistant coating is almost always standard as it is applied when the lenses are made. With higher refractive indexes, there are often more chromatic aberrations, meaning visual disturbances of light, that can be interpreted as blur by some.
What is the difference between CR-39 monomer and polycarbonate monomer lenses?
Lenses made from PPG CR-39 monomer are scratch- resistant, lightweight, have less chromatic aberration than polycarbonate lenses, and stand up to heat and household chemicals and cleaning products.
Are glass lenses scratch resistant?
Glass lenses provide excellent optics, the most scratch resistant lens material and blocks UV light. However, glass lenses are heavy, thick and dangerous if broken and cannot be used in certain frame styles. Some glass is available with a refractive index as high as 1.8 and 1.9.
What are CR-39 lenses used for?
CR-39 plastic lens material is usually only recommended for those with a weak prescription where lens thickness and weight are not a concern and for dress eyewear in which safety is not an issue. CR-39 lenses have a high Abbe value of 59.3 making them the lenses with the least distortion from dispersion/chromatic aberration.