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A Rare Vision Disorder Distorting Faces

In new studies, the secrets of prosopometamorphopsia disorder, which distorts faces, have been unveiled. A woman’s condition improved when she wore orange-tinted glasses.

Definition of the Disorder

Veronica Smith struggles to look at her partner’s face when she sees his features changing – his eyes moving closer then further apart, his face becoming broader then narrower, and his skin moving and shimmering. Smith, who is 32 years old, has been experiencing this phenomenon when looking at faces since she was four or five years old, and while it is sporadic when she looks at someone else’s face, it is more persistent when she looks at her own face.

The Disorder and Its Types

Smith suffers from a rare condition known as prosopometamorphopsia (PMO), where faces appear distorted in shape, texture, position, or color. Many scientists are intrigued by PMO. The late neurologist and author Oliver Sacks wrote a research paper on this disorder that was published in 2014, a year before his death. Brad Duchaine, a professor of psychology and brain sciences at Dartmouth College, explains that some individuals with PMO see distortions affecting the entire face (bilateral PMO), while others only see the left or right half of the face as distorted (unilateral PMO).

Research and Studies

Duchaine has focused his research on prosopagnosia (face blindness) for 25 years, but after collaborating on a study about unilateral PMO published in 2020, he shifted much of his team’s research to PMO. In 2021, he launched a website dedicated to this disorder, and so far, he has contacted 60 individuals describing their specific PMO symptoms. Duchaine and his team are conducting case studies on many of them, including Smith, to better understand their distortions, which could provide insights into how the typical face processing system works.

Causes of the Disorder and Treatment

So far, Duchaine’s research has not revealed a singular cause for PMO, and he anticipates that there are a variety of causes, but he says he would not be surprised if 25 percent of the individuals reaching out to him have distortions related to migraines. There is no proven treatment for this disorder yet. Psychotropic medications, such as selective serotonin reuptake inhibitors (SSRIs), have been tried without significant effect. Duchaine explains that the distortions often fade naturally in individuals who have not experienced them for a long time. Thus, in such cases, it is difficult to ascertain whether newly prescribed medications contributed to the fading of the distortions.

Current and Future Research

In April, Duchaine participated in a review using PMO to discuss fundamental theoretical questions about face representation. These questions include whether face awareness and decisions related to it rely on the same representations or different ones, the nature of facial symmetry, and how each half of the face is represented separately in the visual system. The review also includes 18 open questions highlighting the substantial amount left to learn about PMO and the potential for advancing understanding of facial perception.

Among the cases reviewed in the study, structural brain scans were available for 48 individuals, and there were lesions in visual areas of the brain in 44 of these individuals.

Duchaine suspects that some cases, including Smith’s and a teenager who recalls having problems with faces from a young age, represent a different kind of PMO due to issues in developing face perception mechanisms.

Although his research is ongoing (with the latest findings expected to be published next year), Duchaine and his team discovered that distortions in a significant number of cases can be modified by manipulating facial appearances. They attempted to modify distortions in a few cases and found four individuals whose distortions were affected by color – including Smith, whose distortions become less severe when she wears orange-tinted glasses – and several cases where the presence of corrective glasses on the observed face lessens or eliminates the distortions.

Duchaine states

Duchenne’s fact that 60 people have contacted him in almost three years suggests that the condition may not be as rare as previously thought. He hopes that promoting his work will bring more people suffering from PMO to his website so they can participate in his research and perhaps find some relief.

He says: “They are out there.”

Source: https://www.scientificamerican.com/article/a-rare-visual-disorder-twists-faces-out-of-shape/


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