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.
What Can Surfers do to Protect Their Eyes: Blue Blocking Surf Sunglasses. Even if your surf sunglasses offer 100% UV protection, they likely do not block blue light. For a lens to block blue light in must have a yellow tint. The lenses final color can range from yellow to dark amber. The yellow tint does not necessarily reduce total light intake or make things appear darker. They change the color of blue and green objects, but they do not change the other colors. They will also reduce glare and improve color contrast.