The task resembles the pointing task in which an examinee
reports the orientation of Landolt rings presented according to the
ISO 8596:2009 standard for testing visual acuity. In our experiment,
the participants were required to operate the input device as they
would point in the direction of the lit LED. Similarly, in the previously
developed self-testing vision screener, examinees move the
joystick in the direction of the gap in the Landolt ring.