Which statement best describes CR-39 lenses compared to glass lenses?

Which statement best describes CR-39 lenses compared to glass lenses?

• A. Lenses are lighter
• B. Do not fog as easily
• C. Tinting is more uniform, it can be manipulated, produce less glare, and internal reflections improve visual performance.
• D. They are more prone to scratching

Answer: (C)

CR-39 is a plastic lens material, and the question focuses on how its optical behavior compares with glass, especially regarding tinting and light management. Because CR-39 is a uniform plastic, tinting can be applied very evenly across the entire lens, and the tint density can be tailored during production. That uniform tinting means the wearer sees a consistent color and light transmission from edge to edge, which helps control glare more reliably than with some glass lenses whose tint can vary with thickness and lens geometry. In addition, the material’s optical path permits light to pass with fewer disruptive internal reflections, and, when paired with appropriate coatings, these internal reflections can be managed to support better perceived contrast and visual comfort. So, the description that tinting is more uniform, can be manipulated, and leads to reduced glare with favorable internal reflections best captures how CR-39 lenses behave compared with glass. The other points—being lighter, fogging tendencies, or scratch propensity—are less central to describing how CR-39 affects tinting and overall optical performance.

CR-39 is a plastic lens material, and the question focuses on how its optical behavior compares with glass, especially regarding tinting and light management. Because CR-39 is a uniform plastic, tinting can be applied very evenly across the entire lens, and the tint density can be tailored during production. That uniform tinting means the wearer sees a consistent color and light transmission from edge to edge, which helps control glare more reliably than with some glass lenses whose tint can vary with thickness and lens geometry. In addition, the material’s optical path permits light to pass with fewer disruptive internal reflections, and, when paired with appropriate coatings, these internal reflections can be managed to support better perceived contrast and visual comfort. So, the description that tinting is more uniform, can be manipulated, and leads to reduced glare with favorable internal reflections best captures how CR-39 lenses behave compared with glass. The other points—being lighter, fogging tendencies, or scratch propensity—are less central to describing how CR-39 affects tinting and overall optical performance.