Entoptic Hallucination

In Articles, Knowledge, Phosphenes by James L. Kent

Entoptic hallucination, geometric hallucinations, or phosphenes, are one of the most commonly reported visual effects of psychedelics. Phosphenes are a sensation of light caused by excitation of the retina by mechanical or electrical means. Pressure phosphenes can be created by applying pressure to the eyeballs through closed eyelids; flicker phosphenes are created in response to stroboscopic pulses of light; kinetic phosphenes are created in response to physical impact to the head, sometimes referred to as “seeing stars”. Entoptic hallucinations are differentiated from eidetic (photographic) hallucinations in that they originate within the neural connections between the eye and cortex, as opposed to emerging within the cortex or midbrain. There is evidence that entoptic phosphene patterns have influenced human cultural and religious archetypes since 10,000 BCE.

Entoptic hallucinations fall into predictable geometric patterns and can be measured by formal properties such as form constant, flicker rate, rotation, drift, and decay. Common phosphene forms include web, grid, checkerboard, clover-leaf, spiral, funnel, or more amorphous floating blobs and stars. Phosphene patterns may match recurring patterns in the natural world, such as cells, stars, sand dunes, flowers, clouds, and snakeskin. Evidence suggests that the form constants of phosphenes are directly related to spatial relationships between the ring-like structure of the retinal cells and the grid-like or columnar neural structures of the visual cortex…

Read the full article here Psychedelic Information Theory