When use in sunlight, bright lights, it can cover the direct light on the eye, create interference, so you have a comfortable and cosy environment for rest. It is suitable to use while taking rest, night time sleep, noon time rest or while taking nap in airplane. Wearing eye mask improves eye circulation, removal and relieves eye strain and fatigue, restore ciliary muscle flexibility, reduce eye congestion and avoid light stimulation, anxiety, irritability and even insomnia.