Skimming the original study, it talks about subjects opening and closing their eyes, so I would very much assume that it's entirely related to seeing light (and not about absorbing light through the face or body).
If you get a sleep mask, be sure to look for one designed to not put pressure on your eyes, which are not hard to find if you seek it out. The cheap ones you get at pharmacies and dollar stores put direct pressure on the eyeballs and it's a wonder that anyone can tolerate them and are perhaps even harmful.
I just discovered sleep masks, and they've changed my life.
I bought some on Amazon and got a few different kinds (from the same listing, which is frustrating). All of them have a dome that bulges out over each eye. The most comfortable one I have looks like an eye bra, but unfortunately I can't find a place to order more.
Uhhh, are you sure about that? My ten dollar sleep mask from walgreen doesn't touch my eyes, I don't think it even touches my lashes. Meanwhile every mask I've tried buying online has fit terribly.
I think he's talking about literal dollar priced masks or giveaway sleep masks which are usually just a tiny piece of fabric around something more solid, which attaches to you by means of an elastic band; the band however resists falling/slipping by pushing on your eyeballs.
It sounds like your mask is a bit better, and probably more expensive that the parent means. I've gotten such cheap masks as giveaways and the few I tried were indeed unbearable for sleeping as it felt like someone was crushing my face.
I've been delighted with "Mack's shut-eye shade premium sleep mask" for years. I've only needed to replace my original once.
I started using these when I was a traveling consultant, and now use it only for travel, when taking an afternoon nap, or sleeping in (usually due to illness).
It's very comfortable. The nose bridge is padded. There are two straps, from the top and bottom of the sides, so you don't have a strap routing over the ear. I find it lets in the least amount of light of the masks I've tried precisely because of the comfort features. I don't have to try to arrange the mask in some contorted way to get comfort, so it can sit as intended and block light.
The best I've found isn't sold as a sleep mask, but a "heat massage" mask with beads in it. I never heat it, I only use it as a sleep mask, the beads provide a wonderful, and comfortable, light seal.
If you get a sleep mask, be sure to look for one designed to not put pressure on your eyes, which are not hard to find if you seek it out. The cheap ones you get at pharmacies and dollar stores put direct pressure on the eyeballs and it's a wonder that anyone can tolerate them and are perhaps even harmful.