Certified Paraoptometric (CPO) Practice Exam 2025

Which type of lens material tends to last longer over time?

1. Soft

2. Rigid

3. Contact-free

4. Disposable

The correct answer is: Rigid

The choice of rigid lens material is indeed correct as it typically has a greater longevity compared to other types of lens materials. Rigid lenses, often made from high-quality materials, are designed to resist scratch and wear, maintaining their optical clarity and strength over time. They are also less permeable to tearing and deformation, which helps preserve their shape and correct vision more effectively for an extended period. In contrast, soft lenses, which are made from flexible hydrogel or silicone hydrogel materials, may experience more wear and tear from daily use, leading to a shorter lifespan. Disposable lenses are intended for short-term use, usually replaced daily, biweekly, or monthly, meaning they are not designed for longevity. The term "contact-free" does not relate directly to a specific lens type, making it less relevant in this context. Therefore, the intrinsic properties of rigid lenses, including their durability and stability, make them a preferable option for lasting performance over time.