Closing one's eyes accentuates what you are feeling. Caution: both good and bad. If you are kissing someone and you close your eyes it makes it better. If you are at the dentist and he is doing his thing and you close your eyes, it makes it worse. It heightens our senses.
My woman is very much an open eyes person. The frequent exception being during a build to an orgasm. She'll shut her eyes then, and when it overwhelms her, her eyes will be wide open and nearly popping out. I love that change.
Plenty times I close my eyes quite involuntarily as I begin to ejaculate, if it's a real orgasmic ejaculation with a good few ropes. I don't want to! There are times I get them open again before it's over but most often not. I don't know why that is. My consolation is that, as I complete and open my eyes again she'll be looking right at me with this wonderful smile, enjoying my extreme pleasure and enjoying my spunk deep in her. That smile is always a deep, deep pleasure for me. I want to see the whole of it!