Study Unveils Two Noninvasive Ocular Markers of Age-related Cognitive Decline

While the authors of a recent study caution that their findings are preliminary and exploratory, the presented data support a potential link between diminished cognitive function, altered oculomotor behavior and reduced visual and autonomic response. These graphs from the study show the number of microsaccade occurrences (A: horizontal, B: vertical) across different age groups. Photo: Oh S, et al. J Eye Mov Res. March 5, 2026. Click image to enlarge. Certain ocular metrics can serve as objective indicators of cognitive decline—a precursor to neurodegenerative diseases, notably Alzheimer’s disease. A recent study used eye-tracking technology to identify two noninvasive markers of early neurological change: microsaccades and pupil size variations. The findings indicated a notable increase in microsaccade frequency associated with aging, further intensified in individuals with lower cognitive scores, while rates of pupil constriction and dilation declined substantially as age progressed.The study recruited 70 participants categorized into three age groups: those in their 20s, 60s and 70s. Among the older participants, the 70s cohort was further divided into cognitively normal and cognitively impaired subgroups based on their Mini-Mental State Examination scores. The researchers used eye-tracking technology to record participants' eye movements and pupil responses while they maintained a steady gaze on a central fixation point during the experimental assessments. The results demonstrated a clear trend of increasing microsaccade frequency with age. “Participants in their 20s exhibited low microsaccade frequency with predominantly horizontal orientation, reflecting stable and efficient oculomotor control,” the researchers reported in their paper, published in Journal of Eye Movement Research. On the other hand, “older participants, especially those in their 70s, showed not only significantly increased microsaccade frequency but also greater directional dispersion—including a significant rise in vertical microsaccades.”Notably, this effect was even more pronounced among elderly participants with lower cognitive scores, “suggesting that age-related decline in attentional regulation and motor control systems may contribute to increased microsaccadic instability,” the researchers wrote. Together, these findings support a potential link between diminished cognitive function and altered oculomotor behavior.The analysis also showed a significant decline in pupil constriction and dilation rates as individuals aged, indicating that autonomic pupil responses were compromised over time. Specifically, average constriction rates decreased from -51.6% in the youngest group to -38.4% in the oldest, while dilation rates also notably diminished from 114.9% to 63.4%.“These age-related reductions are consistent with prior evidence demonstrating a progressive decline in pupil size dynamics across the healthy lifespan, reflecting age-related changes in autonomic and neuromodulatory function,” the study authors explained. They added that ”the diminished amplitude of pupil size variation suggests a potential link to age-related decline in neural function and may represent an indicator of reduced visual and autonomic response capability in older adults.”Interestingly, the study showed that the speed of pupil constriction and dilation remained relatively stable across all age groups, which the researchers note “suggests that while the strength of the autonomic response declines with age—potentially due to reduced parasympathetic and sympathetic nervous system function—the underlying neural timing mechanisms remain functionally intact.”Based on these results, the researchers believe these metrics may serve as valuable indicators for assessing cognitive impairment in aging populations.“The convergence of these two physiological markers—microsaccades and pupil size variation—offers valuable insight into how neurodegenerative processes influence involuntary eye behavior,” the researchers concluded. They noted, however, that these findings are preliminary and exploratory, since the study was cross-sectional and failed to include patients with clinically diagnosed Alzheimer’s disease. “Therefore, the proposed approach should be regarded as a potential screening framework rather than a validated diagnostic tool,” they wrote.Click here for the journal source. Oh S, Nairuz T, Park SJ,  Lee JH. Simultaneous analysis of microsaccades and pupil size variations in age-related cognitive impairment using eye-tracking technology. J Eye Mov Res. March 5, 2026. [Epub ahead of print].  This article was developed by the editorial staff in conjunction with experts in the field. In the process, AI may have been among the editorial tools used to meet the goals of human editors, who approved all content.