Which lens material is commonly used for children's eyewear due to its impact resistance?

• A. Polycarbonate
• B. Hi-index
• C. CR-39
• D. Trivex

Answer: (A)

The main thing this question tests is safety in eye protection for kids, specifically how well a lens material can withstand impact. Polycarbonate is inherently tough and absorbs energy during impact, making it highly resistant to breaking or shattering. Its lightweight nature also helps with comfort for children who wear glasses all day, and it easily meets safety standards for eyewear.

Because of these attributes, polycarbonate is the go-to material for children’s lenses—combining strong impact resistance with practicality and cost.

Hi-index lenses are valued for being thin and light, which helps with high prescriptions, but they don’t offer the same level of impact resistance as polycarbonate. CR-39 is a common, affordable plastic lens, yet it has lower impact resistance, making it less ideal for kids’ safety needs. Trivex offers good impact resistance and clarity, but it’s less widely used for children due to higher cost and availability compared with polycarbonate.