What is the primary function of scratch-resistant coating?

The primary function of scratch-resistant coating is to protect lenses from scratches. This type of coating forms a protective layer on the surface of the lenses, making them more durable and resistant to damage caused by daily wear and tear. Without this coating, lenses can easily get scratched, which can impair vision and necessitate costly replacements.

Furthermore, while scratch-resistant coatings contribute to the longevity and practicality of eyewear, they do not typically reduce the weight of the lenses, enhance clarity, or improve color perception in a significant way. These aspects may be addressed by other lens treatments or materials but are not the main purpose of a scratch-resistant coating. Therefore, the focus of such coatings is solely on preventing scratches, making option C the correct answer.