Resin lenses are lightweight and impact resistant, suitable for most daily wear; high index lenses are thinner and lighter, suitable for people with high counts, reducing the weight and edge thickness of the glasses and improving the aesthetics.
The lenses of color-changing eyewear contain photosensitive materials that darken under UV light and return to clear indoors or under low UV light. This property makes a pair of glasses suitable for both outdoor and indoor wear.
The main functions of sunglasses are to protect against UV rays, reduce glare, protect the eyes from bright light, and enhance comfort during outdoor activities. Some styles also have a polarizing feature to further reduce reflected and scattered light.
Myopia glasses are used to correct nearsightedness (clear vision at near and blurred vision at far), and the lenses are usually concave lenses; farsightedness glasses are used to correct farsightedness (clear vision at far and blurred vision at near), and the lenses are usually convex lenses.