Final answer:
Sunglasses with optical effects like polarization and photochromic lenses provide vision enhancement and UV protection. Polarized sunglasses reduce glare by filtering out horizontally aligned light waves. To check for polarization, rotating one pair of sunglasses in front of another should block the light at two points.
Step-by-step explanation:
Sunglasses offer a variety of optical effects to enhance vision and protect the eyes from harmful ultraviolet (UV) rays. Among these effects, sunglasses can be equipped with photochromic lenses which have the ability to darken in the presence of sunlight and become clear indoors. This is due to the presence of organic microcrystalline molecules in the lenses that react to UV light, changing the lens properties. Polaroid sunglasses are known for their capability to significantly reduce the glare from reflected surfaces, such as water or glass. This is achieved through a characteristic of light called polarization. Polarization is the process where light waves are oriented in a particular direction, typically on a vertical axis. This allows polarized sunglasses to block out glare more effectively as it targets reflected light which is usually horizontally polarized. To test whether sunglasses are polarized, a simple method is the GRASP CHECK. By placing one pair of sunglasses in front of another and rotating them, if the sunglasses are polarized, light will be blocked completely at two points due to the sunglasses' lenses filtering out horizontally aligned light waves. When considering safety and protection from UV radiation, full coverage eye protection is recommended. Materials like polycarbonate, used in some plastic lenses, provide significant protection by blocking the majority of UV rays and are more effective than glass lenses in this regard.