Eye & Vision · UV & Blue Light
Blue light, UV400 and what a coating can and cannot do
By the OSAWALLA editorial team · 2026-09-03 · 5 min read
UV400 means the lens blocks wavelengths up to 400 nm — essentially all UVB and most UVA. That is a real, measurable protection benefit, and it matters outdoors.
Blue-light filtering is a different claim. Screens emit far less blue light at the eye than daylight does, and the evidence for screen-related eye damage is weak. What blue-light coatings reliably change is contrast and, for some people, evening alertness.
Buy UV400 for protection. Buy blue-light filtering for comfort at night if it helps you. Do not buy either expecting it to fix tired eyes — that is usually a focusing-load problem.
This article is general information, not medical advice. OSAWALLA devices are wellness products and are not intended to diagnose, treat, cure or prevent any disease. Speak to a clinician about any health concern.
