A matrix of 12 letters will be presented followed by a bar marker. Your task is to read the letter in the position to the left of the marker. Fixate on the + target and then click the 'Display' button while holding your fixation. Please scroll down the page. A matrix of 12 letters will be presented followed by a mask and then a bar marker. Your task is to read the letter in the position to the left of the marker. Fixate on the + target and then click the 'Display' button while holding your fixation. Please scroll down the page. A matrix of 12 letters will be presented followed by a mask that does not completely encircle the letter area and then a bar marker. Your task is to read the letter in the position to the left of the marker. Fixate on the + target and then click the 'Display' button while holding your fixation.