For the archaeological term, see Entoptic phenomena (archaeology). In Helmholtz's words: "Under suitable conditions light falling on the eye may render visible certain objects within the eye itself.

Ophthalmogram showing blood vessels in front of the retina. Their shadow is the cause of the blue field entoptic phenomenon. In a technique known as blue field entoptoscopy, the effect is used to ...

Also seen during these altered states, and later painted on the rock wall, were so-called “entoptic visions”, visuals from a ...

Lahelma, Antti 2011. David S. Whitley:Cave Paintings and the Human Spirit. The Origin of Creativity and Belief. Norwegian Archaeological Review, Vol. 44, Issue. 2, p ...

A line drawing of the Internet Archive headquarters building façade. An illustration of a heart shape "Donate to the archive" An illustration of a magnifying glass. An illustration of a magnifying ...