Brad Duchaine¹, Antônio Mello¹, Sydney Fortner², Alexis Kidder^1,3; ¹Dartmouth College, ²University of California, Santa Barbara, ³National Institute of Mental Health

Prosopometamorphopsia (PMO) is a visual perceptual disorder in which faces appear distorted. Fewer than 100 cases of PMO have been reported in the literature, and the great majority are brief, single-case reports. However, because our laboratory has been contacted by more than 250 people who have experienced face distortions, we have conducted in-depth investigations of PMO as a means to better understand typical face perception and have also evaluated interventions that reduce distortions. Here, we present a collection of visualizations that illustrate the face distortions perceived by 15 individuals with PMO, along with synopses of their case histories. Our aim in displaying these visualizations is to provide vision scientists and healthcare professionals with illustrations that convey the nature and severity of the distortions present in PMO. Distortions affecting face shape have received the most attention in the literature, but the distortions in our participants often alter other aspects of facial appearance as well, including the texture, color, and depth of facial surfaces. In some cases, facial appearance is transformed so intensely that participants have great difficulty making judgments about fundamental characteristics of faces such as age, sex, gaze direction, and race. While the variation between cases means that tasks must often be tailored to particular participants, these distinct forms create opportunities to investigate numerous theoretical questions from visual neuroscience. Reports provided by many participants indicate that their verbal descriptions of face distortions were dismissed or misinterpreted in clinical settings, with some individuals even being prescribed antipsychotic medication under the assumption that their perceptual experiences reflected broader psychiatric pathology. These difficulties highlight the need for greater clinical awareness of PMO, and we hope that disseminating these visualizations will contribute to more accurate diagnosis and improved care.

Acknowledgements: Hitchcock Foundation award to BD