The present study investigated the effects of a simulated monocular scotoma on binocular shape discrimination hyperacuity and whether the effects differed, if any, on central, parafoveal and peripheral vision. Five participants identified radial frequency patterns (distorted circles) amongst two baseline circles, to establish modulation thresholds. A mixed repeated measures design was applied, which consisted of two within-subject independent variables: viewing conditions (binocular vision, left eye, right eye and binocular vision with a simulated monocular scotoma) and the eccentricities in the visual field (central, parafoveal and peripheral vision); these were targeted using three different sizes of radial frequency patterns. It was hypothesised that, when simulating a monocular scotoma, modulation thresholds would be lower for central and parafoveal vision but no difference would be expected for peripheral vision. Analysis revealed that there was no significant difference between conditions when comparing the modulation thresholds for central and peripheral vision. The findings suggest that modulation thresholds were similar across all four conditions for these eccentricities, though this was expected for peripheral vision. Conversely, as predicted there was a difference in thresholds for parafoveal vision, when comparing the thresholds in the right eye and simulated scotoma condition.

Rhea Mistry is a psychologist at Chrysalis Associates, a UK-based center specializing in the assessment and treatment of developmental trauma and attachment difficulties. The organization is dedicated to providing dynamic and effective services to its clients.