By examining a person’s eye movements, we are able to find out about
a range of cognitive functions, such as attention
and short term memory.
Following the progress or a ball thrown in the air, or
a car travelling round a track requires the eyes to move
in a certain way, ‘smooth pursuit eye movement’.
When reading or scanning a room, however, we normally use
rapid or ‘saccadic’ eye movements. Eye movements
are convenient and useful to measure for finding out about
psychiatric disorders like schizophrenia- they do not involve
invasive procedures and can reveal information about a range
of cognitive functions. Studies from across the world consistently
show that people with schizophrenia perform worse than controls
on eye tracking tests; during smooth pursuit tests, they
often intersperse saccadic eye movements with smooth eye
pursuit. Importantly, their close relatives also show these
eye tracking abnormalities, indicating that eye tracking
has a genetic component.