A sleep mask should feel snug enough to stay put when you turn over, but not so tight that it presses on your eyes, causes a headache, leaves deep marks or makes any part of your face feel numb. You should be able to slide a fingertip under the band without fighting it.
Start looser than you think
Put the mask over your eyes, place the band level around the back of your head and tighten it only until the mask stops slipping. Lie down in your usual position before deciding. A fit that feels fine while standing can become rather more opinionated against a pillow.
Turn your head both ways and open and close your eyes. The mask should not rub your eyelids or shift every time your cheek meets the pillow.
Watch for signs it is too tight
- Pressure on the eyes or bridge of the nose
- A headache or aching around the temples
- Deep marks that linger
- Numbness, tingling or soreness
- The band riding upward because it is over-tensioned
A faint temporary fabric line can happen, especially after side sleeping, but discomfort is not the price of keeping light out. Loosen the band and reposition the mask rather than enduring it.
If loosening creates light leaks
Tightness cannot fix every fit problem. Light at the nose may mean the mask shape does not match your nose bridge, while light at the sides may come from a band sitting too high or low. Reposition it first.
A contoured mask should rest around the eyes rather than flattening them. Face shapes vary, so a mask that seals neatly for one person may leave an edge gap for another. More pressure is not always the answer.
Recheck after a few nights
Bands can relax slightly with use, and your preferred setting may differ between back and side sleeping. Adjust in small steps. If the mask has a buckle, keep it away from the spot where your head presses into the pillow.
The correct fit is pleasantly uneventful: the mask stays on, your eyes are comfortable and you stop thinking about the band. If you wake wanting to tear it off, it is offering fairly direct feedback.
