American Board of Ophthalmology (ABO) Practice Exam

What is the main disadvantage of standard plastic lenses compared to polycarbonate lenses?

1. They are heavier

2. Less impact-resistant

3. More prone to scratching

4. Higher optical distortion

The correct answer is: Less impact-resistant

The primary disadvantage of standard plastic lenses when compared to polycarbonate lenses is their lower impact resistance. Polycarbonate lenses are specifically engineered to be more durable and able to withstand significant impact, making them a favored choice for safety eyewear and for individuals engaged in sports or high-risk activities. Standard plastic lenses, on the other hand, are relatively more fragile and do not offer the same level of protection against physical trauma. This characteristic makes polycarbonate lenses particularly advantageous for settings where lens durability is paramount, such as in children's eyewear or among those who work in industrial environments. While standard plastic lenses may be lighter, can be scratched more easily, and may exhibit some degree of optical distortion, their lack of impact resistance is the most critical concern in situations where lens safety is required. This makes polycarbonate lenses the preferred option for those needing robust, reliable eye protection.