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Closed-eye hallucination. Closed-eye hallucinations and closed-eye visualizations ( CEV) are hallucinations that occur when one's eyes are closed or when one is in a darkened room. They should not be confused with phosphenes, perceived light and shapes when pressure is applied to the eye's retina, or some other non-visual external cause ...
Visual Snow can appear at any time, but it commonly appears at birth, late teenage years, and early adulthood. Visual snow syndrome ( VSS) is an uncommon neurological condition in which the primary symptom is that affected individuals see persistent flickering white, black, transparent, or colored dots across the whole visual field.
Entoptic phenomena (from Ancient Greek ἐντός (entós) 'within', and ὀπτικός (optikós) 'visual') are visual effects whose source is within the human eye itself. (Occasionally, these are called entopic phenomena, which is probably a typographical mistake.) In Helmholtz 's words: "Under suitable conditions light falling on the eye ...
An artist's representation of how some people may see phosphenes by retinal stimulation. A phosphene is the phenomenon of seeing light without light entering the eye. The word phosphene comes from the Greek words phos (light) and phainein (to show). Phosphenes that are induced by movement or sound may be associated with optic neuritis.
Synesthesia. A person with synesthesia may associate certain letters and numbers with certain colors. Most synesthetes see characters just as others do (in whichever color actually displayed) but they may simultaneously perceive colors as associated with or evoked by each one. Synesthesia ( American English) or synaesthesia ( British English ...
Computer vision syndrome ( CVS) is a condition resulting from focusing the eyes on a computer or other display device for protracted, uninterrupted periods of time and the eye's muscles being unable to recover from the constant tension required to maintain focus on a close object.
For example, a white page under blue, pink, or purple light will reflect mostly blue, pink, or purple light to the eye, respectively; the brain, however, compensates for the effect of lighting (based on the color shift of surrounding objects) and is more likely to interpret the page as white under all three conditions, a phenomenon known as ...
An afterimage is an image that continues to appear in the eyes after a period of exposure to the original image. An afterimage may be a normal phenomenon (physiological afterimage) or may be pathological ( palinopsia ). Illusory palinopsia may be a pathological exaggeration of physiological afterimages. Afterimages occur because photochemical ...