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The spatial resolution of the human visual field decreases considerably from the center to the periphery. However, several studies have highlighted the importance of peripheral vision for scene categorization. In Experiment 1, we investigated if peripheral vision could influence the scene categorization in central vision. We used photographs of indoor and outdoor scenes from which we extracted a central disk and a peripheral ring. Stimuli were composed of a central disk and a peripheral ring that could be either semantically congruent or incongruent. Participants had to categorize the central disk while ignoring the peripheral ring or the peripheral ring while ignoring the central disk. Results revealed a congruence effect of peripheral vision on central vision, as strong as the reverse. In Experiment 2, we investigated the nature of the physical signal in peripheral vision that influences the categorization in central vision. We used either intact, phase-preserved, or amplitude-preserved peripheral rings. Participants had to categorize the central disk while ignoring the peripheral ring. Results showed that only phase-preserved peripheral rings elicited a congruence effect as strong as the one observed with intact peripheral rings. Information contained in the phase spectrum (spatial configuration of the scene) may be critical in peripheral vision.

Primary open-angle glaucoma (POAG) firstly mainly affects peripheral vision. Current behavioral studies support the idea that visual defects of patients with POAG extend into parts of the central visual field classified as normal by static automated perimetry analysis. This is particularly true for visual tasks involving processes of a higher level than mere detection. The purpose of this study was to assess visual abilities of POAG patients in central vision. Patients were assigned to two groups following a visual field examination (Humphrey 24–2 SITA-Standard test). Patients with both peripheral and central defects and patients with peripheral but no central defect, as well as age-matched controls, participated in the experiment. All participants had to perform two visual tasks where low-contrast stimuli were presented in the central 6° of the visual field. A categorization task of scene images and human face images assessed high-level visual recognition abilities. In contrast, a detection task using the same stimuli assessed low-level visual function. The difference in performance between detection and categorization revealed the cost of high-level visual processing. Compared to controls, patients with a central visual defect showed a deficit in both detection and categorization of all low-contrast images. This is consistent with the abnormal retinal sensitivity as assessed by perimetry. However, the deficit was greater for categorization than detection. Patients without a central defect showed similar performances to the controls concerning the detection and categorization of faces. However, while the detection of scene images was well-maintained, these patients showed a deficit in their categorization. This suggests that the simple loss of peripheral vision could be detrimental to scene recognition, even when the information is displayed in central vision. This study revealed subtle defects in the central visual field of POAG patients that cannot be predicted by static automated perimetry assessment using Humphrey 24–2 SITA-Standard test.