According to ANSI standards for glass lenses, which tempering method is required?

• A. Heat tempered or chemically tempered
• B. Heat tempered
• C. Laminated
• D. Chemically tempered

Answer: (A)

The main idea is that ANSI safety standards for glass ophthalmic lenses require the lens to have higher impact resistance through tempering. Both heat tempering (thermal tempering) and chemical tempering achieve this by creating a strong compressive surface layer, which helps lenses resist breakage on impact. Because the standard accepts either method, the correct choice is the one that states heat tempered or chemically tempered.

Laminated glass isn’t a tempering method itself; it’s a separate safety approach that uses layers bonded together. While laminated glass provides safety advantages, it doesn’t satisfy the requirement of being tempered, which is why it isn’t the correct choice here.