Via Nautilus, Rose Eveleth on meditation as an ancient method of harnessing one’s senses to open new doors of perception:
After five years of practicing meditation, subject number 99003 began to see the lights: “My eyes were closed, [and] there would be what appeared to be a moon-shaped object in my consciousness directly above me… When I let go I was totally enveloped inside this light… I was seeing colors and lights and all kinds of things going on… Blue, purple, red.”
Buddhist literature refers to lights and visions in myriad ways. The Theravada tradition refers to nimitta, an vision of a series of lights seen during meditation that can be taken to represent everything from the meditator’s pure mind to a visual symbol of a real object.
Hallucinations are relatively well-documented in the world of sensory deprivation, and they dovetail with the lights seen by meditators. Where meditators see shimmering ropes, electrical sparks, and rays of light, the sensory deprived might see visual snow, bright sunsets, and luminous fog.