UV radiation is categorized into three types: UV-A, UV-B, and UV-C. UV-A and UV-B rays are the most common types that reach the Earth's surface. UV-C rays are largely absorbed by the Earth's atmosphere and do not pose a significant threat. UV-B rays are known to cause sunburn and can damage the outer layers of the eye, while UV-A rays can penetrate deeper, potentially affecting the delicate structures within the eye. High-quality UV-blocking sunglasses can effectively filter out both UV-A and UV-B rays, providing comprehensive protection.