Entoptic phenomenon

Entoptic phenomena (from Ancient Greek ἐντός (entós) 'within' and ὀπτικός (optikós) 'visual'), occasionally and incorrectly referred to as entopic phenomena, are visual effects whose source is within the human eye itself.

This variance is not surprising because the specific aspects of the eye that produce these images are unique to each individual.

Because of the variation between individuals, and the inability for two observers to share a nearly identical stimulus, these phenomena are unlike most visual sensations.

This notwithstanding, there is enough commonality among main entoptic phenomena for their physical origin to now be well understood.

The phenomenon appears as one or more light disks crossed by dark blurry lines (the shadows of the lashes), each having fringes of spectral colour.