Understanding Prosopometamorphopsia (PMO)

What is PMO?

Face processing depends on a complex network of brain regions, and dysfunction within this network can produce a wide variety of face processing impairments. When faces or parts of faces are perceived as distorted, the condition is known as prosopometamorphopsia (PMO). “Prosopo” comes from the Greek word for face prosopon while “metamorphopsia” refers to perceptual distortions.

Not surprisingly, people with prosopometamorphopsia often find it disturbing to look at other people’s faces. Fortunately, most cases last only a few days or weeks, but in some people, face distortions sometimes last for many years. Around 75 cases reports on people with PMO have been published, so the condition appears to be quite rare.

Prosopometamorphopsia comes in different forms. The condition causes features to appear distorted in a variety of ways -- they may droop, appear smaller or larger than normal, be out of position, or seem stretched. PMO is typically classified based on the region of the face that is affected by distortion. We currently have little understanding about why people experience different types of PMO, but it is one of the many questions that we are interested in investigating.

Full-face prosopometamorphopsia (Full-face PMO) and hemi-prosopometamorphopsia (hemi-PMO) are two most prominent subtypes of PMO. Click on the names or the tabs at the top to learn more.

Research participants needed

Little is known about the different types of prosopometamorphopsia because few cases have been studied. Our lab is very interested in studying people with PMO. We hope that our research can lead to a deeper understanding of PMO and also how face processing works in typical brains. In addition, this research may help us identify interventions that reduce or eliminate face distortions in PMO.

If you are experiencing prosopometamorphopsia or know someone who is, we would love to hear from you. You can either contact Professor Brad Duchiane (see contact information below) directly via email, or contact us using this form and we will contact you as soon as we can.

Author's Information

Dr. Brad Duchaine, Ph.D.

Professor at Dartmouth College
Department of Psychological and Brain Sciences
Co-Founder of faceblind.org

I’m a professor in the Department of Psychological and Brain Sciences at Dartmouth. Much of our lab’s research is focused on neuropsychological investigations of face processing. If you’re interested in our research, you can learn more here.

To get in touch about PMO or other types of category-specific metamorphopsia, please email me at: bradley.c.duchaine@dartmouth.edu (or use link below).