Photochromic lenses are suitable for various environments, especially in environments with strong sunlight. For example, when exposed to ultraviolet and short wave visible light under sunlight, the lens will darken and reduce light transmittance; In indoor or dark environments, the light transmittance of the lens will increase, restoring its transparent state. This automatic adjustment feature can reduce visual fatigue and protect the eyes from the harm of sunlight, ultraviolet rays, and glare.