Eye strain is the result of pain and fatigue of the eyes, often accompanied by a headache. Eye fatigue happens when the muscles in and around your eyes become tired from intense use (from straining to focus) – similar to what happens to other muscles in your body when they’re put through rigorous exercise or overuse.
It should come as no surprise that eye fatigue and eye strain have everything to do with the quality of your eyewear. If you wear cheap, low-quality safety eyewear for hours at a time on the job, you’ll likely start to experience discomfort. Though your eyes won’t be permanently damaged because of eye strain, the discomfort and fatigue it causes will influence your productivity. Having to stop what you’re doing to take your eyewear off, give your eyes a break, and refocus is considered lost time. In extreme situations, eye strain can cause impaired vision, leading to lower visual awareness of your surroundings. This affects your overall ability to detect safety hazards, which can come with very real consequences.
With Brand X high-quality lenses, rays of light pass through the optical center and suffer no refraction; that is, they pass deviated. As a result, any strain on the eye is eliminated.
For further reading about safety glasses: https://www.allaboutvision.com/safety/safety-glasses.htm