Sleeping with eyes open

[flipflopsonfifthavenue]

DS2 is 5 weeks and when he naps during the day when I check on him he's often lying there with eyes half open and eye balls rolling/flickering. He's also making lots of grunting whimpering noises and little wind smiles/grimaces.
I know that babies do a lot of REM sleep - is this what this is? Is he really asleep when he does this?! Am assuming that if he was awake, he's be, well, awake?!

I've seen myself sleeping and I have one eye open. Dh was freaked out and took a photo. Then I was freaked out when he showed me!
I have been reassured that it's totally normal. Normal for a 5 week old too.

Yup, my DS is known to sleep with his eyes open. Bit confusing if I come home from work and check in on him after he's gone to bed

My lg does the one eye open thing too. I just stroke her nose and she shuts her eyes properly :)

My son has always done this (he's now 4 months). It looks a bit freaky - sometimes his eyes are really quite wide open! My mother-in-law says a few people on her side of the family have done it too.

My husband and my DS do this freaks me the fuck out!

I do that too. That looks creepy, but it's not something to worry about.