Charles Bonnet syndrome (CBS)
Recurring vivid visual hallucinations — grids, patterns, miniature people, animals — in people with significant vision loss who are otherwise mentally well.
Open VisualSim →What it looks like
CBS hallucinations fall into two categories. Simple hallucinations: brick-like grids, lattices, or repeating geometric patterns overlaid on real surfaces. Complex hallucinations: detailed images of people (often miniature, sometimes wearing costumes and hats — "Lilliputian"), faces with staring eyes, animals, or landscapes. Episodes last seconds to minutes and recur from a few times a week to many times a day. The hallucinations are usually colorful, can be still or moving, and the person retains insight that what they're seeing isn't real.
Who gets it
CBS occurs in people with significant vision loss — most often elderly patients with age-related macular degeneration, glaucoma, or diabetic retinopathy. It's thought to be the brain's visual cortex generating activity to "fill in" for missing sensory input. It is not a mental illness and not a sign of dementia.
When to see a doctor
Tell your eye doctor or primary care doctor if you're experiencing CBS — diagnosis is reassuring, and they can rule out other causes. Many patients feel afraid to mention these hallucinations for fear of being thought "crazy," but CBS is a recognized neurological phenomenon.
Also known as
CBS · Visual release hallucinations