Objective:

Background:

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. 

Design/Methods:

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).

Results:

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. 

Conclusions:

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.