When I did my pool training, we were told to remove our masks and swim the length of the pool along the bottom. All three of us wore contacts, so they said to close our eyes and feel our way along the tile stripes. I thought it was rather silly since I always opened my eyes in a pool and even in the ocean (but not with my contacts in). I did the drill and it did something wonderful for me. I had been greatly bothered by the bubbles coming out of my regulator in front of my face, but once I couldn't see them, it stopped bothering me and never did again. One of the other students said the same thing happened for him.
I wonder if there isn't a related explanation.
Back when I used to teach scuba schools the way it is usually done, with the students kneeling on the bottom of the pool, the mask removal for one minute really bothered some of the students because of the bubbles going past their faces and over their noses while they waited for the time to be up. Most of them had their eyes closed, so seeing or not seeing the bubbles did not make a difference. When I switched to teaching skills to students in a horizontal, buoyant attitude, that problem vanished. It had nothing to do with not being able to see the bubbles; it had everything to do with the act that when you are in a normal swimming position, the bubbles don't go past your face and eyes and nose any more--they go past your cheeks and ears. When you were picking your way across the bottom of the pool, you had no choice but to be in a proper swimming position, so you did not have bubbles in front of your face--whether your eyes were open or closed.