Eye movements in Duane Syndrome

Humans frequently make eye movements to explore their daily environment.
Because of the wealth of visual information in our environment, there is a
continuous competition between the various elements in the visual field for the
next eye movement. Crucial is therefore the correct selection of the relevant
element (*target*) in the presence of irrelevant elements (*distractors*).
Previous studies have shown that distractors interfere with target processing
in that eye movement responses to a target are slower and less accurate.
Moreover, in a small proportion of trials, the eyes are captured by the
distractor in that eye movements are erroneously directed to the distractor. It
is currently unknown which mechanisms are involved in this interference by a
distractor.

In this study, we will systematically investigate the influence of distractors
on target processing in patients with Duane Syndrome. These patients are
impaired in executing eye movements in horizontal directions. It will be
investigated whether a distractor interferes when it is presented at a location
towards which no eye movement can be executed. This will reveal whether the
ability to execute an eye movement to a presented distractor is a crucial
factor for a distractor to interfere.

A group (n=20) of adult participants with Duane Syndrome is invited to
participate in a behavioral study to investigate the mechanisms underlying the
competition between visual targets. A control group (n=20), matched in age,
will be tested using the same experimental set-up.

This is a non-therapeutic study in which the risks are negligible and the
burden is minimal. The experiments are non-invasive, so there is no need for
special preparation for the participants. There are no health risks doing the
tests. The data are primarily used for research purposes.