Visual hallucinations range from simple flashes of light and geometric patterns to fully detailed images of people, animals, or entire scenes that appear completely real. What someone sees depends largely on what’s causing the hallucination, whether it’s a neurological condition, vision loss, a migraine, or a substance. Some hallucinations are fleeting and abstract, while others are vivid enough to be mistaken for reality.
Simple Visual Hallucinations
The most basic hallucinations have no recognizable form. They show up as flashes of light, shapeless blobs of color, or modifications in how light and shadow appear. These are sometimes called photopsias, and they can be stationary or move across your visual field. People describe seeing colored or colorless dots, lines, or brief bursts of light that appear and disappear quickly.
A step up from raw flashes are geometric patterns: honeycombs, spirals, webs, grids, and zigzag lines. These don’t look like real objects. They look more like abstract shapes overlaid on whatever you’re actually seeing. Simple hallucinations like these originate from activity in the most basic visual processing areas of the brain, which handle raw shapes and edges rather than recognizable images.
Complex Visual Hallucinations
Complex hallucinations are an entirely different experience. Instead of abstract shapes, people see detailed images of faces, human figures, animals, or objects. These images can look strikingly realistic, sometimes appearing in full color with fine detail, and the person experiencing them may initially believe what they’re seeing is actually there. In some cases, people see familiar faces: loved ones, neighbors, coworkers from their past or present. In others, they see strangers, animals, or miniature figures sometimes described as “Lilliputian” hallucinations because of their small size.
These more elaborate hallucinations involve higher-level visual processing areas in the brain, the regions that piece together shapes into recognizable objects and scenes. That’s why they can look so convincing. A person with Parkinson’s disease might see a person standing in the doorway. Someone with severe vision loss might see a detailed brick wall pattern or an animal sitting on a piece of furniture. The hallucinations can last seconds or minutes, and they sometimes recur in similar forms.
What Hallucinations Look Like With Vision Loss
When the brain stops receiving normal visual input due to vision loss, it sometimes generates its own images to fill the gap. This is known as Charles Bonnet syndrome, and it affects people with conditions like macular degeneration, glaucoma, or cataracts. The hallucinations aren’t a sign of mental illness. They’re a byproduct of the brain compensating for missing visual data.
People with Charles Bonnet syndrome report a wide range of images. Some see repeating patterns: brick walls, netting, webs, or grid-like designs that tile across their visual field. Others see recognizable figures, including people they know, animals, or detailed landscapes. The hallucinations often appear vivid and lifelike, but the person typically knows they aren’t real. They might see a face hovering in the room or a cat sitting on the table that vanishes when they try to touch it. The images tend to appear without warning, last for a variable amount of time, and stop on their own.
What Migraine Auras Look Like
Migraine auras are a common form of visual disturbance that many people experience before or during a headache. The most well-known type is called a fortification spectrum because its shape resembles the walls of a medieval fort. It typically starts as a small hole of light or a cluster of bright geometric lines in your visual field. Over the course of several minutes, it expands into a sickle or C-shaped arc, with shimmering zigzag lines along its leading edge. As it grows, it may drift across your field of vision before fading.
Not everyone gets the classic zigzag pattern. Some people see bright spots, flickering lights, or shimmering areas instead. Auras can also come with a partial loss of vision called a scotoma, where a portion of your visual field goes temporarily blank or dark. The whole experience usually lasts between 20 and 60 minutes and resolves on its own. Unlike many other hallucinations, migraine auras follow a fairly predictable progression, which makes them easier to recognize once you’ve experienced one.
Size and Distance Distortions
Some visual disturbances don’t create new images but warp the ones you’re already seeing. In a condition sometimes called Alice in Wonderland syndrome, objects appear dramatically larger or smaller than they actually are, or seem closer or farther away than their real position. A doorknob might look the size of a basketball, or a room might seem to stretch into the distance. In some cases, objects appear to shrink and recede at the same time, creating a disorienting tunnel-like effect.
These distortions are most common in children and are often associated with migraines, infections, or epilepsy. They’re usually brief, lasting seconds to minutes, and the person is typically aware that what they’re seeing doesn’t match reality. The experience can be unsettling, but it differs from a true hallucination in that real objects are still present. They just look wrong.
Drug-Induced Visual Effects
Psychedelic substances like LSD produce visual experiences that fall on a spectrum from mild distortions to full hallucinations. At lower intensities, people see colors become more saturated, surfaces appear to “breathe” or ripple, and geometric patterns emerge on walls, skin, or other textured surfaces. These patterns often resemble fractals, spirals, or lattice-like grids, and they tend to shift and morph continuously.
At higher doses, the visual effects can escalate into hallucinations of objects, creatures, or entire environments that don’t exist. Stimulant drugs produce a different profile. With prolonged use or sleep deprivation, stimulants are more likely to cause “shadow people” or brief flickers of movement in peripheral vision rather than the colorful, patterned visuals associated with psychedelics. Schizophrenia-related hallucinations also tend to be distinct: people with schizophrenia more commonly report seeing faces or human figures rather than abstract geometric patterns.
How Real Do They Look?
One of the key features that defines a true hallucination is that it carries the full sensory weight of a real perception. The person isn’t imagining something with their eyes closed. They’re seeing it projected into the real world, layered on top of or replacing their actual surroundings, with detail and solidity that makes it indistinguishable from reality in the moment. This is what separates hallucinations from illusions, which are misinterpretations of something that’s actually there (like mistaking a coat rack for a person in a dark room).
There’s also a middle category sometimes called pseudohallucinations, where a person sees something vivid but recognizes it as unreal. These experiences may lack the full spatial quality of a true hallucination. They might feel more like they’re inside the mind rather than out in the world, and the person can sometimes influence or dismiss them. Many people with Charles Bonnet syndrome or migraine auras fall into this category. They see something clearly, but they know it isn’t there.
The degree of realism also depends on the underlying cause. Hallucinations in Parkinson’s disease, which affect up to 60% of patients over the course of their illness, often start as subtle “presence” sensations or brief glimpses of movement before progressing to fully formed visual images. Hallucinations caused by psychedelics tend to have a shifting, unstable quality that makes them feel dreamlike rather than grounded. Hallucinations from delirium or high fever can be intensely real and frightening, with the person unable to distinguish them from actual events.