narmz,

everything is vibrating. everything has a frequency, or compilation of frequencies. when you realize this your senses become one that spans through the spectrum. rainbows fading into rainbows. entire being a sensor for the cosmic light of consciousness, symphoniously.

Personally, I always close my eyes and physically look up when in trance. sometimes they flicker, but most of the time they're just looking up. (which is a physical trigger in some meditations)