Eyecatcher Visual Field Test Protocol

The equipment for the Eyecatcher visual field test is shown in Figure 1A. Stimuli were displayed on a Microsoft Surface Pro 3 (Microsoft, Redmond, WA): a portable “tablet computer,” containing a screen measuring 25.4 × 16.9 cm (28.5° × 19.2° at the viewing distance of ∼50 cm). Eye movements were recorded monocularly at 50 Hz using a Tobii EyeX eye-tracker (Tobii Technology, Stockholm, Sweden): a low-cost (∼$100), near-infrared, remote eye-tracker, with a precision of < 0.6°.40 (link) Participants were sat approximately 50 cm from the screen. However, no chin rest was used, and participants were free to move their head. A constant stimulus size on the retina was maintained by scaling the screen-size of the stimulus trial-by-trial, based on the participant's current viewing distance (as measured by the EyeX eye-tracker, which also contains integrated head-tracking). The test was programmed in C# and R,41 using custom code.