American Board of Ophthalmology (ABO) Practice Exam

Plastic and tempered glass lenses are classified as which type of lenses?

1. Breakable

2. Impact resistant

3. Water resistant

4. Lightweight

The correct answer is: Impact resistant

Plastic and tempered glass lenses are classified as impact-resistant lenses due to their specific manufacturing processes that enhance their durability and ability to withstand force. Plastic lenses, which are typically made from polycarbonate or other polymers, have inherent properties that make them less likely to shatter upon impact while maintaining clarity. This characteristic makes them ideal for protective eyewear, particularly in environments where there is a risk of high-velocity impacts. Tempered glass lenses undergo a heat treatment process that increases their strength compared to regular glass. This process helps to make them more resistant to breaking; when they do break, they tend to shatter into small, blunt pieces rather than sharp shards, which minimizes the risk of injury. Both types of lenses are specifically designed and tested to resist impact, making them suitable for various applications, including safety glasses and sports eyewear. While the other classifications such as breakable, water resistant, and lightweight are attributes that may apply to various types of lenses, the defining characteristic of both plastic and tempered glass lenses is their enhanced ability to resist impact compared to standard materials.