Reduced peripheral vision in glaucoma and boundary extension

International audienceClinical relevancePeripheral vision is known to be critical for spatial navigation yet, visual cognition, has been the object of few interests in glaucoma; a pathology that affects peripheral vision. BackgroundSpatial memory was assessed with a paradigm developed by Intraub and Richardson (1989) known to induce a robust memory distortion called “boundary extension” in which participants erroneously remember seeing more of a scene than was present in the sensory input.Methods 15 patients with glaucoma and 15 age matched normally sighted controls took part in the experiment. Participants were shown 10 photographs of natural scenes randomly displayed for 0.5s or for 10s. Following each scene the participant was asked to draw it from memory. ResultsOn average, boundary extension was larger, by 12%, for patients than for controls, but the difference was significant for 4 photographs. Patients tended to add more space between the object and the edges than there was between the objects and the border of the photograph. A control experiment in which participants were asked to draw isolated objects without scene context resulted in a significant reduction of the memory distortion in both groups but patients still drew the objects smaller than controls. ConclusionThe results suggest that the reduced field of view in glaucoma has an impact on spatial memory for scenes and on perception of size