Types of Coatings
Plastic lenses are lighter than traditional glass lenses but they scratch more easily. Scratched lenses can be irritating for the wearer and look unsightly. Scratch-resistant coatings are available to protect against damage and prolong lens life.
Spectacle lenses can be provided with anti-reflection coatings which virtually eliminate distracting reflections off the lens surfaces. Reducing reflected light is particularly helpful for computer users and for night driving. Anti-reflection coatings also improve the cosmetic appearance of your glasses and can make thick lenses look thinner.
Multi-coated lenses incorporate a combination of coatings - anti-reflection, scratch-resistant, water repellent and UV - to combine to improve the properties of your spectacles.
Transistions or Photochromic
Photochromic lenses are a unique type of tinted lenses and are light-adjusting lenses which react sunlight. They are ideal if one wants to combine sunglasses and prescription glasses in only one pair. This feature offers great comfort and can change from light to dark depending on the amount of ultraviolet light. When you are indoors, the tint will be very light. And when you are outdoors, it will get dark depending on the direct exposure to sunlight.