Describes the surface defects of a lens that are not necessarily optically critical and do not necessarily impair its function. Usually described in terms of scratch and dig.
SPHERICAL VS. ASPHERIC LENSES
HOW THEY’RE USED IN IMAGING APPLICATIONS
Optical Lenses are often categorized by their shape. Two common surface shapes are spherical and aspherical. Each offers unique characteristics that make it suitable for different use cases.