Imagine if every time you saw a face, it appeared distorted. For those who have a very rare condition known as prosopometamorphopsia, which causes facial features to appear distorted, that is reality.

As the website on what is known as PMO explains, “‘Prosopo’ comes from the Greek word for face ‘prosopon’ while ‘metamorphopsia’ refers to perceptual distortions.” The distortions can affect the shape, size, color, and position of facial features, and PMO can last for days, weeks, or even years.

A new Dartmouth study published in the “Clinical Pictures” section of The Lancet reports on a unique case of a patient with PMO. The research is among the first to provide realistic visualizations of how a patient experienced facial distortions.

The patient, a 58-year-old male with PMO, sees faces without any distortions when viewed on a screen and on paper but sees distorted faces that appear “demonic” when viewed in-person. The case is especially rare because he does not see distortions of faces across all contexts.