ABO NOCE Practice Test

What is the standard thickness for lenses in the United States?

1. 2mm thick

2. 1.5mm thick

3. 1mm thick

4. 0.5mm thick

The correct answer is: 1mm thick

The standard thickness for lenses in the United States is typically around 1.5mm. This thickness is practical as it balances durability and optical performance. Lenses that are too thin may not hold up well to everyday wear and tear, and they can also be more prone to chipping or breaking. A thickness of 1.5mm is often used as a baseline for many common prescriptions, providing sufficient material for lens curvature and coating applications to enhance both vision and protective properties. While a measurement of 2mm may offer extra durability, it is less commonly cited as the standard thickness for all lenses; it might be applied in specialty lenses or for certain materials. The thickness of 1mm is considered too thin for standard lenses, which could compromise structural integrity. Similarly, 0.5mm is significantly underestimated for typical ophthalmic lenses, leading to high fragility. Therefore, 1.5mm serves as the most widely recognized and accepted standard thickness for lenses in optical practice.