Optical class refers to the quality of the lens and is categorised as 1, 2, or 3. Tests are carried out to ensure that the lens is free from distortions that can cause strain on the eyes. 

Optical class 1 indicates that the eye protector can be worn for a continuous extended period of time, whereas optical class 3 eyewear should not be worn for long periods. 

All JSP safety spectacles, goggles, and applicable face shields are optical class 1.