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RESEARCH PRODUCT

The Effect of Central Vision Loss on Perception of Mutual Gaze

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People with central vision loss (CVL) often report difficulties with social interactions and reduced social functioning.1, 2 A limited access to the nonverbal visual cues inherent to effective communication can be a disadvantage in social interactions. Wang and Boerner3 reported that for people with vision impairment, difficulty in social situations was due either to the individual’s own lack of ability to perceive visual cues or other people’s lack of understanding. The facial region has been noted as an important source of nonverbal visual information relevant to social situations.4 Prior studies of individuals with CVL due to age-related macular degeneration have focused primarily on difficulty with recognizing and discriminating faces and facial expressions.5–8 However, the ability to perceive mutual gaze [knowing whether somebody else is looking at you] also provides important nonverbal social cues.9, 10 For example, a gaze in your direction may be a cue signaling turn-taking in a conversation, or can indicate certain interpersonal attitudes, such as hostility or attraction. Therefore, an inability to perceive mutual gaze could potentially be detrimental to an individual’s social relationships and interactions. However, difficulty with gaze perception has, to our knowledge, never been evaluated in a low vision population. Here we report a study in which we evaluated mutual gaze judgments of individuals with CVL compared to normally sighted controls. Although gaze direction can in principle be judged on the basis of the position of the iris relative to the visible portion of the surrounding sclera,11, 12 other cues, such as head orientation are known to be factored into gaze direction judgments.13 Detecting mutual gaze is a higher-order visual function based on a complex interaction between these visual cues.12, 14, 15 Therefore, it is hard to predict exactly how gaze perception of individuals with CVL might be affected. Reduction of low-level visual functions, including visual acuity and contrast sensitivity, may or may not translate into difficulties in gaze perception. To quantify the functional ability of participants with CVL to judge mutual gaze, we used an interactive gaze perception task developed by Gamer and Hecht.16 The task involves adjustment of the gaze direction of a computer-generated virtual head, which was previously validated against a real person.16 Mutual gaze with another person is perceived to occur over a range of gaze directions, which Gamer and Hecht referred to as the cone of gaze.16 The gaze perception task quantifies both the direction of this cone of gaze and the width (the range of gaze directions that are perceived as ‘being looked at’). The task has been able to measure differences in gaze perception between controls and people with social phobias,17 but, so far, has never been used to evaluate mutual gaze performance of visually-impaired observers. We hypothesized that participants with CVL would have greater difficulty perceiving mutual gaze than normally-sighted controls as they would have greater difficulties seeing the visual cues used to make judgments about the virtual head’s gaze direction. We predicted that these gaze perception difficulties would manifest as greater judgment variability on the gaze perception task. Furthermore, depending on how they might respond to uncertainties about mutual gaze, their judgments might become either more conservative or more liberal, resulting in either a narrower or a wider gaze cone width, respectively, when compared to peers with unimpaired vision. Finally, we compared gaze perception performance of CVL participants with a bilateral central scotoma (a scotoma that encompasses the fovea) to CVL participants without a bilateral central scotoma.