To investigate variations in fixational eye movements among normal children, adolescents, and adults.

Fixational eye movements are fundamental for sustaining stable visual perception. Understanding the age-related changes in fixational eye movements is important when developing diagnostic and therapeutic means for various neuro-ophthalmologic conditions.

Our study included 56 healthy participants (21 males, 35 females; age 3 to 72). We collected fixational eye movement data using infrared video-oculography and a high-resolution video-based eye tracker. Binocular horizontal and vertical eye positions were recorded under binocular, left-eye, and right-eye viewing conditions. We measured the frequency and amplitude of fixational saccades of ≤1° (FS≤1) and >1° (FS>1), median drift velocity, and fixational stability (bivariate contour ellipse area, BCEA). The eye movement data were categorized into three age brackets: Group 1 (3-9 years), Group 2 (10-19 years), and Group 3 (≥ 20 years).

In numerous viewing conditions, Group 1 and 2 displayed lower frequency of FS≤1 but a higher frequency of FS>1 compared to Group 3, whereas the median drift velocity appeared to be lower in Group 1 and 2 compared to Group 3. In monocular viewing conditions, the logBCEA was significantly larger in Group 1 compared to Group 3. However, the interocular ratios of BCEA showed no significant differences among the three groups.

Collectively, these findings suggest the neural control of fixational eye movement is still under maturation in children and adolescents. The interocular ratio of BCEA may serve as a useful clinical parameter since its value remains stable across the lifespan.