Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Examples of the Landolt-C discrimination task, unflanked (single presentation of a Landolt-C), flanked-horizontal (participants choose the orientation of the middle Landolt-C, flanked horizontally by two other Landolt-C elements) and flanked-vertical.
