Hey there,
First post and all. Newbie here. I've had a couple attempts and a little experience.
On my third trip, I ended up in a bit of a state mid-trip where, I had been told to keep your eyes closed if you want to see things best and that opening your eyes could actually take you out of the trip. But when you're 'in it' you can't really much control much of anything. I couldn't tell if my eyes were actually closed or not, because I couldn't feel them, and I started to get worried that they were actually opening. Whole thing seemed to shut the experience down for me.
So I bought a sleeping mask. I work overnights and sleep during the day so it does double-duty and I'm looking forward to using it. Can't say yet it's my 'recommendation', but I can't see myself going for another trip without it on.