Assessing the impact of central and peripheral obstructions on visual behavior: insights from gaze-contingent eye-tracking studies

This dataset is a collection of image stimuli, as well as gaze tracks collected using visual field masks, such as central and peripheral scotoma, in order to assess the way people with visual field loss process visual stimuli in digital environments.

This dataset is structured as follows :

• Stimuli: 125 fullHD images (1920x1080) used during the experiment trials; 4 fullHD images used during the training phase.
• Trials_metadata:
  • Psychopy_outputs: various callbacks and logs files from the Psychopy experiment
  • trials_metadata: .csv files containing metadata such as stimuli order and timestamps.
• Raw_eyetracking_outputs: subfolders containing the raw .edf files output by the Eyelink 1000+ eye-tracker. .edf files are divided into groups of 25 successive stimuli displayed.
• Raw_gaze_points: .csv files, containing the raw gaze points locations for each subject, stimulus and mask. Blinks, invalid coordinates and out-of-bounds gaze points are already removed from these files.
• Fixations: .csv files (one per image per participant) containing eye fixations locations extracted from the raw gaze points using a I-VT algorithm with a saccade velocity threshold of 45 deg/s.

Experiment

Images

This database consists of 100 images collected from personal collections and various public image datasets, such as the CityScapes and the KITTI-360 datasets, covering a variety of themes, including landscapes, people, actions, and nature.
Images had a 1920 x 1080 pixel resolution (FullHD) and were shown on a screen with the same resolution. 

Eye-tracking data collection

The stimuli were presented to a group of 37 observers, with normal or corrected-to-normal vision. We used a table-mounted EyeLink 1000 Plus eye-tracker, working at a fixed rate of 1000Hz, with a chin rest to ensure data accuracy. Participants were informed that they would observe images both with and without simulated visual field impairments, and the two types of masks used were described. They were also told that the only task is to view the images freely. 

To familiarize participants with the different types of masks, four training images (distinct from the trial dataset) were provided in the training phase, with each image presented in the three conditions -- peripheral mask, foveal mask, and control (no mask) -- with varying mask sizes. 
In the trial phase, stimuli were displayed in a random order, with a randomly generated playlist ensuring no three consecutive stimuli were of the same image. A uniform gray screen was displayed between each stimulus. 

Viewing distance was set to be 90cm.
Eye-tracker calibration was carried out using a 9-point calibration protocol, i.e., 9 points were sequentially and randomly shown on the screen, where the observer should fixate their gaze. 
Additionally, calibration was performed after every 25 displayed images.

Each image was presented to the observers for a 5-second period.

Each image in the database was presented to the observers under different conditions :
    - The image without any obstruction, referred to as the control condition (C). 
    - Peripheral mask (P) simulating a tunnel vision, with two circular mask size variations (one individual mask for each eye): 1.5° and 4.5° radius of field of view, referred to as P1 and P2, respectively. 
    - Foveal mask (F) simulating a central scotoma, also with two size variations: 1.5° and 4.5° radius of obstruction, referred to as F1 and F2, in that order.