Period Costs. Period costs are expenses that are easier to attribute to times and accounting periods than actual production processes or finished goods. Typically, managerial accountant want to classify expenses in categories that can improve operations. Manufactures tend to focus on functional classifications.
The amber color of these impact-resistant polycarbonate lenses block short-wavelength blue light and 100% of ultraviolet (UV) light, thus providing additional protection against cataract formation and the development of macular degeneration, while increasing contrast on both sunny and bright hazy days.
Blue blocking lenses are typically amber in color and are made to filter out blue light from your vision. The circadian rhythm depends on inputs such as exposure to blue light in order to moderate your sleep and energy patterns.