Can hallucinations be a sign of vision loss?

1 answer | Last updated: Dec 02, 2016
A fellow caregiver asked...

My father, who has vision loss, sometimes sees things that aren’t there. He otherwise seems perfectly healthy mentally. In fact, he's aware that he's visually hallucinating. Is this common, and what causes it?


Expert Answers

Lylas Mogk, M.D. is an ophthalmologist and director of the Henry Ford Visual Rehabilitation and Research Center in Grosse Pointe and Livonia, Michigan, and the author of Macular Degeneration: The Complete Guide to Saving and Maximizing Your Sight.

Approximately 30 percent of individuals with vision loss see visual hallucinations or "phantom images." This is called Charles Bonnet syndrome, named after the Swiss philosopher who first described it over 200 years ago. When it happens, the individual sees a recurring full-color, life-like image of people, flowers, animals, fences, or other common objects but understands that they aren’t real. The images aren’t accompanied by sound or smell and don’t make contact with the viewer, although they may move (it can be somewhat like watching a silent movie). These experiences may last a few years, and then they generally subside.

They're nothing to worry about, but if you or your father find them disconcerting, you may want to read the chapter called "I See Purple Flowers Everywhere" in my book, Macular Degeneration: The Complete Guide to Saving and Maximizing Your Sight. It discusses Charles Bonnet syndrome, presents patients' experiences, and provides illustrations.