Quick answer: Sometimes, like any lens. Glasses fog when warm, moist air hits a cooler lens, common with face masks, stepping indoors from the cold, or a hot drink. It's not specific to blue light glasses, and it's easy to manage.
How to stop them fogging
- Use an anti-fog spray or anti-fog wipe on the lenses
- With a mask, fit the nose wire snugly and rest the glasses on top of the mask edge
- Let the lenses adjust to room temperature when coming in from the cold
- A thin film of lens-safe soap, buffed off, can reduce fogging in a pinch
- Make sure the frames sit slightly away from your face for airflow
The bottom line: Blue light glasses fog up the same way any glasses do, from warm, damp air on a cool lens. An anti-fog spray, a snug mask fit, and letting lenses acclimate keep them clear.