Visual fixation development in children.

BACKGROUND

The ability to keep steady fixation on a target is one of several aspects of good visual function. However, there are few reports on visual fixation during childhood in healthy children.

METHODS

An infrared eye-tracking device (Orbit) was used to analyse binocular fixation behaviour in 135 non-clinical participants aged 4-15 years. The children wore goggles and their heads were restrained using a chin and forehead rest, while binocularly fixating a stationary target for 20 s.

RESULTS

The density of fixations around the centre of gravity increased with increasing age (p < 0.01), and the time of fixation without intruding movements increased with increasing age (p = 0.02), while intruding saccades decreased with increasing age (p < 0.01). The number of blinks and drifts did not differ between 4 and 15 years, and there were no significant differences with regard to gender or laterality in any of the investigated variables. No nystagmus was observed.

CONCLUSION

This study establishes values for visual fixation behaviour in a non-clinical population aged 4-15 years, which can be used for identifying children with fixation abnormalities.