What is the function of anti-fog coating on lenses?

The function of anti-fog coating on lenses is to prevent condensation on the lenses. This is particularly important in situations where temperature changes lead to the formation of moisture on the surface of lenses, such as when moving from cold to warm environments or during physical activities where sweat might cause fogging. Anti-fog coatings are specially designed to create a hydrophilic surface that reduces the surface tension of water, allowing moisture to spread evenly across the lens rather than forming droplets that impair visibility.

The other options do not specifically relate to the primary function of anti-fog coatings. While preventing scratching can be accomplished by other types of coatings, enhancing visual clarity and improving color perception involve optical properties that are not addressed by anti-fog technology. Thus, the correct understanding of the role of anti-fog coating emphasizes its purpose in maintaining clear vision by minimizing condensation.