What do you mean by opening your eyes?

You are talking about two concepts: open eyes and wandering at will. Buddhists say that the human eye has four levels, namely 1, the naked eye of ordinary people, 2, the true eye with refined qi, 3, the eye of heaven, 4, the eye of epiphany, 5, the eye of dharma, and 6, the highest level of Buddha's eye. But generally speaking, the ability of perspective and farsightedness is collectively called the eye of the sky, and the specific entity of the eye of the sky is called the pineal gland in modern science.

Walking around in the body at will in Qigong is called Shen Yuan's OBE, which is the highest state of refining Qi, refining Qi and restoring the spirit to the air.

However, all the above are said in the book, and it is difficult to distinguish between true and false. I haven't practiced those effects. But what you said in your dream, I believe most people have. Not to mention in dreams, even during the day, sometimes a scene will make people feel deja vu. Moreover, this feeling is particularly strong. It's obviously the first time you meet someone, the place you've been or the thing you've experienced, but it seems like you've experienced it once. The mystery is puzzling. Maybe there are past lives, or people can really roam in the void at some time.