Instead, the data suggest that mechanical factors, such as elastic restoring forces and eyelid resistance, play a significant role alongside neural mechanisms in determining how the eye moves. The study focused on visually guided saccades, which are the rapid, voluntary shifts of gaze. Although saccades are generally believed to be generated by similar neural mechanisms in all directions, prior measurements have consistently shown directional differences in their movement characteristics.

The specific causes of these asymmetries remained unclear before this investigation. To address this, the researchers utilized an EyeSeeCam Sci 2 video-oculography system with a sampling rate of 500 Hz. This high-resolution setup allowed for precise capture of horizontal and vertical eye movements in a cohort of 28 males and 20 females, with a mean age of 40.38 years.

In the horizontal plane, the team measured saccades with amplitudes of 5, 10, 15, and 20 degrees in both centrifugal (away from the nose) and centripetal (toward the nose) directions. The results indicated that for larger amplitudes of 15 and 20 degrees, saccades in the medial hemifield were faster than those in the lateral hemifield. This pattern was observed in both centrifugal and centripetal directions.

Additionally, centripetal saccades were significantly faster than centrifugal ones. These findings suggest that the mechanical environment of the eye, rather than a simple neural command difference, contributes to the velocity profile of horizontal eye movements. Vertical saccades exhibited similar directional dependencies.

When measuring 5, 10, and 15-degree vertical movements, saccades in the upper hemifield were significantly faster than those in the lower hemifield for the largest amplitude of 15 degrees. This asymmetry was present in both upward and downward directions. Furthermore, centripetal saccades in the upper hemifield were faster than centrifugal ones, mirroring the horizontal findings.

The authors attribute these vertical differences to physical properties, including viscous resistance from eyelid coverage in the lower eye position, which may impede downward movements. Latency and amplitude analyses provided further insight into the mechanics of these movements. No clear trends were observed in horizontal saccade latency or amplitude across different directions.

However, vertical movements exhibited distinct patterns. Centripetal saccades showed shorter latencies, and upward saccades had larger amplitudes compared to downward movements. These subtle differences indicate that the initial phase of vertical eye movements is also influenced by the physical state of the periocular tissues.

The study notes that while neural mechanisms initiate the saccade, the final execution is modulated by the mechanical constraints of the eye socket. The authors specifically attribute the medial-lateral eye position difference to the interaction between saccades and vergence. The study emphasizes that saccade-vergence interaction is a key factor in explaining horizontal asymmetries.

Other directional asymmetries are attributed to physical properties such as the elastic restoring force in the centripetal direction. Additionally, viscous resistance from eyelid coverage in the lower eye position was identified as a factor slowing down downward saccades. The findings underscore the significant influence of periocular tissues on saccade motor characteristics.

While the brain sends neural commands to initiate saccades, the final execution of these movements is heavily modulated by the physical properties of the eye and its surroundings.

Subject of Research: Directional differences in saccade motor characteristics and the role of periocular tissue mechanics

Article Title: Directional differences in saccades

Article References: Jono, T., Takahashi, K., Hara, H., Kudo, Y., Schneider, E., Shiono, M., Tanaka, F., & Johkura, K. (2026). Directional differences in saccades. Frontiers in Neurology, 17, 1945647. https://doi.org/10.3389/fneur.2026.1945647

Image Credits: AI Generated

DOI: 10.3389/fneur.2026.1945647

Keywords: saccades, oculomotor control, eye movement, neuro-ophthalmology, periocular tissue, video-oculography, saccade velocity, horizontal saccades, vertical saccades, elastic restoring force, Directional, differences

The report, authored by Antonio Denia-Lafuente and Belén Lombardero of the Unidad de Oído y Vértigo at Hospital Universitario Nuestra Señora del Rosario, follows a 56-year-old woman with a lifelong history of CN, migraine, and episodic vertigo across five years of clinical visits. The patient arrived at the emergency department after three days of severe headache followed by vertigo, persistent imbalance, nausea, and bilateral tinnitus that was more pronounced in the left ear, without hearing loss. A neurological workup, including brain computed tomography, revealed spontaneous left-beating nystagmus and findings consistent with episodic migraine. She received vestibular sedatives and rizatriptan benzoate and was referred for further evaluation.

Her history was striking. She had experienced episodes of vertigo lasting two to three days for approximately 27 years, sometimes while in bed, and tinnitus in the left ear for the previous three years. Since reaching menopause, these episodes had been associated with migraines, sometimes preceding them, with photophobia and phonophobia, and occasionally antedated by bilateral ear pressure and tinnitus, especially in the left ear. She described fluctuating, non-permanent hearing loss, frequent spatial disorientation in open spaces, and a history of childhood strabismus. Her Dizziness Handicap Inventory (DHI) score of 60 indicated a substantial impact on daily life.

Clinical and videonystagmography examination using an Interacoustics VN415 system revealed a high-frequency, horizontal, jerk, left-beating nystagmus in primary gaze, which intensified in left gaze and changed direction, decreasing in right gaze. The CN limited standard vestibular assessment, including observation of spontaneous nystagmus, head shaking, vibration-induced nystagmus, and head impulse tests, as well as videonystagmography. Despite this, the right Dix-Hallpike test with VNS elicited, after two to three seconds, intense mixed upbeat and right-torsional nystagmus lasting about 18 seconds with severe vertigo. The patient was diagnosed with CN, vestibular migraine, and right posterior canalolithiasis benign paroxysmal positional vertigo (BPPV) — a diagnosis of BPPV in a patient with CN that the authors report for the first time.

The technical heart of the report lies in the vHIT recordings. The video head impulse test measures the vestibulo-ocular reflex (VOR), the rapid eye movement that stabilizes gaze when the head turns, by tracking eye motion during brief, passive head rotations at high frequencies. Each of the six SCCs can be probed individually. In this patient, the CN waveform conditioned the recorded lateral VOR eye movements: with spontaneous nystagmus suppression disabled, the system registered a low acceptance rate and frequent rejections, so results were reported with suppression enabled, showing a normal acceptance and rejection rate. Lateral HIMP revealed reduced gain values and impaired bilateral horizontal VOR generation, while vertical canal VOR gains remained normal for each SCC, without refixation saccades.

Perhaps the most intriguing finding was the spectrum of compensatory saccades — rapid corrective eye movements that substitute for a deficient VOR — observed during passive head impulses. These included very early saccades with near-zero latency or occurring at the onset of head acceleration, early covert saccades during head acceleration, and covert saccades occurring during the deceleration phase of the impulse, at approximately 100 to 140 milliseconds. These responses were predominantly rightward and frequently exhibited a double-peaked saccadic pattern. To the authors’ knowledge, very early saccades during passive head impulses have not been specifically characterized in the literature, and only a few studies have reported early saccades in vestibular lesions under these conditions.

The authors believe that repeated use of the passive HIMP protocol trained this patient to detect and reduce retinal slip errors by gradually increasing the number of saccades, adjusting their latency during the deceleration phase, and improving gaze stability and functional recovery. Over the five-year follow-up, the saccadic response shifted from a dispersed pattern to a clustered organization of covert saccades, compatible with compensated vestibular deficits, with consistently low gains. The authors suggest that congenital nystagmus does not interfere with vertical VOR function, allowing normal and abnormal vestibular response patterns to be observed, which they emphasize as important for routine study.

The SHIMP protocol — the suppression head impulse test, which removes compensatory saccades and generates anticompensatory saccades instead — proved essential for accurate interpretation. SHIMP VOR gains were comparable on both sides at two visits but remained below HIMP values, and saccade analysis showed low bilateral anticompensatory amplitudes, greater to the left, with 5 percent rightward covert compensatory saccades at three months that were absent at two years nine months. The presence of SHIMP anticompensatory saccades in a difficult-to-assess lateral VOR can be a very useful sign of vestibular function, and anticompensatory saccade generation through training can promote vestibular compensation and functional recovery.

Functionally, the patient’s trajectory was one of gradual improvement. At three months, positional tests were normal; at two years nine months, they revealed left posterior canalolithiasis, which was resolved with an Epley maneuver after a mild COVID-19 infection. At four years three months, after another mild COVID-19 infection, a right Dix-Hallpike test revealed posterior canalolithiasis, again resolved with an Epley maneuver. At four years six months, her symptoms had improved, with a DHI score of 30. At four years eight months, she reported being satisfied using both pairs of glasses, with a DHI score of 28 and a Visual Function Questionnaire (VFQ-25) score of 91 percent. At five years, she reported better global steadiness, no vertigo, greater visual stability, and fewer headaches, with a DHI score of 20.

From the patient’s perspective, at two years nine months she reported that before coming to the office, she missed work at least twice a month on days when she had disabling vertigo and that, after treatment, she has not missed work again. At four years eight months and at five years, progressive improvement persisted, with a marked reduction in vertigo and greater visual stability, which contributed to improved balance and well-being. The authors conclude that vestibular function assessment in CN and vertigo using vHIT and VNS enables accurate diagnosis and successful management of the most common vertigo syndromes, and they recommend an updated binocular vision study in these patients. The findings support the value of vHIT and videonystagmoscopy, providing new perspectives for assessing and managing the most frequent vertigo syndromes in CN and vertigo.

Subject of Research: Vestibular function assessment with vHIT and videonystagmoscopy in congenital nystagmus and vertigo

Article Title: Vestibular function assessment using the video head impulse test and videonystagmoscopy in congenital nystagmus and vertigo: a long-term case report

Article References: Denia-Lafuente, A., & Lombardero, B. (2026). Vestibular function assessment using the video head impulse test and videonystagmoscopy in congenital nystagmus and vertigo: a long-term case report. Frontiers in Audiology and Otology, 4, Article 1917636. https://doi.org/10.3389/fauot.2026.1917636

Image Credits: AI Generated

DOI: 10.3389/fauot.2026.1917636

Keywords: congenital nystagmus, vertigo, video head impulse test, videonystagmoscopy, semicircular canals, vestibulo-ocular reflex, BPPV, vestibular migraine, saccades, vestibular rehabilitation, case report, Dix-Hallpike test

The idea behind eye movement training, often abbreviated ET, rests on a simple observation of human physiology: vision is not a passive process but an active one, deeply intertwined with the body’s control of posture and movement. Three distinct oculomotor systems are at play whenever we look around. Smooth pursuit allows the eyes to track a moving object fluidly, as when following a ball across a field. Saccades are the rapid, ballistic jumps the eyes make from one fixation point to another, essential for scanning a scene or reading a page. And the vestibulo-ocular reflex, or VOR, stabilizes gaze by counter-rotating the eyes when the head moves, keeping the visual world steady during locomotion. Because balance depends on the continuous integration of visual, vestibular, and proprioceptive signals, researchers have long speculated that sharpening these eye movement systems might also sharpen the body’s ability to stay upright.

Testing that idea rigorously in children, however, has been difficult. Most prior work on eye movement training has focused on adults, older adults, or clinical populations, and questions about whether children would adhere to a long training program, and whether such training would produce lasting effects in a developing nervous system, remained open. The Japanese team set out to address the feasibility question directly by designing an intervention that children could perform entirely at home, guided by an instructional video delivered through a system called SUKUBARA, and monitored automatically through recorded playback times.

The study enrolled 30 community-dwelling school-aged children in Japan, of whom 28 completed the full 24-week program. The participants had a mean age of 10 years, with an age spread of roughly one year, and 12 of the 28 completers, or 43 percent, were girls. Each child performed a daily training routine combining three types of exercises: smooth pursuit tasks, saccadic eye movement tasks, and exercises based on the vestibulo-ocular reflex at a doubled gain, sometimes written as VOR x2, which challenges the reflex to work harder than it naturally does. While performing these exercises, the children watched an instructional video at home, and the system automatically logged how long the video was played, giving the researchers an objective measure of adherence rather than relying on self-report.

Adherence, it turned out, was respectable for a home program lasting half a year. Over the 24 weeks, the children accumulated an average of 9.2 hours of total video viewing time, with a standard deviation of 3.6 hours. Spread across the training period, that works out to about 4.6 sessions per week, or roughly 4.6 with a standard deviation of 1.8. For a daily program, that means most children completed the routine on around half of the available days, a figure the researchers treated as evidence that the intervention was feasible for this age group when delivered through a familiar video-based format at home.

To capture what changed, the team measured a battery of outcomes before and after the intervention. The primary outcome was the index of postural stability, or IPS, assessed in four different conditions, which quantifies how steadily a child can stand. Secondary outcomes included one-leg standing time with eyes both open and closed, grip strength, jump height, and two functional tests specifically designed to probe ocular motor-related visual performance: eye-hand coordination, abbreviated EHC, and horizontal moving digit identification, abbreviated HDI. In the EHC test, children must coordinate their hand movements with what their eyes are tracking, while the HDI test requires identifying digits that are moving horizontally, a task that directly loads the pursuit and saccadic systems. Statistical significance was set at a p-value below 0.05, and appropriate paired analyses were used to compare pre- and post-training measurements.

The results revealed a strikingly selective pattern. Significant improvements appeared in eye-hand coordination, which rose from an average of 33 to 36 points, with standard deviations of 5 in both cases and a p-value below 0.001, and in horizontal moving digit identification, which increased from 12 to 14 points, with standard deviations of 3 and 4 respectively and a p-value of 0.010. One-leg standing time with the eyes closed also improved substantially, rising from a median of 23 seconds to a median of 35 seconds, with a p-value of 0.004, and grip strength increased from a median of 16.5 kilograms to 18.0 kilograms, with a p-value of 0.002. In contrast, the four indices of postural stability showed no significant change, nor did jump height or one-leg standing time with the eyes open.

That selectivity is scientifically telling. The tasks that improved, eye-hand coordination and moving digit identification, are precisely the ones that depend most directly on the oculomotor systems being trained, suggesting that the exercises did what they were designed to do at the level of visual function. The improvement in one-leg standing with eyes closed is more puzzling at first glance, since removing vision makes balance harder, not easier, and the researchers note it alongside grip strength gains that could reflect general growth and maturation over six months in children around 10 years old. Because the study used a single-group design without a control arm, natural development, seasonal activity changes, and practice effects on the tests cannot be ruled out as contributors to any of the observed changes. The absence of improvement in the formal postural stability indices, meanwhile, indicates that the training did not translate into steadier standing under the conditions measured.

Perhaps the most informative analysis came from correlating each child’s change scores with their training frequency. Only one outcome showed a significant positive correlation with how often the children trained: eye-hand coordination, with a correlation coefficient of 0.570 and a p-value of 0.003. This dose-response relationship is meaningful because it suggests that the improvement in eye-hand coordination was not merely noise or maturation but was linked to the amount of training actually performed. Children who watched and followed the instructional video more often tended to gain more in the visual-motor task most closely tied to the exercises. No such relationship appeared for balance measures, grip strength, or jump height, reinforcing the conclusion that the training’s clearest effect was on ocular motor-related visual function itself.

The authors are careful about what their findings do and do not establish. They conclude that the 24-week home-based eye movement training program with SUKUBARA was feasible for school-aged children and has the potential to improve ocular motor-related visual function, but they emphasize that the effects on balance were limited and require confirmation in controlled trials. The study was prospectively registered with the University Hospital Medical Information Network Clinical Trials Registry under registration number UMIN000055747 on November 4, 2024, and, at the journal’s request during editorial assessment, was additionally registered retrospectively with the Japan Registry of Clinical Trials as jRCT1032250334 on September 3, 2025. The research received support from the University of Tsukuba through a management grant and through the Advanced Research Initiative for Human High Performance and the Human Smart City Connection programs, and the authors declared no competing interests.

For a field increasingly interested in telerehabilitation, remote monitoring, and home-based training systems, the study offers a practical proof of concept. Children as young as 10 can sustain a structured, video-guided exercise program for six months when it is embedded in their home routine, and objective adherence data can be captured automatically without burdening families. The selective gains in eye-hand coordination and moving digit identification hint that oculomotor training could eventually find a place in programs aimed at visual-motor skills in developing children, whether for sport, learning, or rehabilitation. But the balance question remains open. If eye movement training is to be recommended as a tool for improving postural stability in children, randomized controlled trials with appropriate control groups will need to determine whether the limited balance effects seen here reflect a true absence of benefit, a dose too small or too brief to matter, or simply the difficulty of detecting balance changes in children whose bodies are changing rapidly anyway. Until then, the study stands as an honest first step: a feasible home program that trained the eyes, showed a clear dose-response where the eyes were tested, and left the balance question, for now, unanswered.

Subject of Research: Effects of home-based eye movement training on balance and oculomotor function in school-aged children

Article Title: Effects of eye movement training on balance and ocular motor function in community-dwelling Japanese school-aged children: a pilot study using a single-group intervention

Article References: Suzuki, Y., Kamada, H., Hirata, S., Hongo, G., Shibuya, I., Hada, Y., & Suzuki, K. (2026). Effects of eye movement training on balance and ocular motor function in community-dwelling Japanese school-aged children: a pilot study using a single-group intervention. BMC Pediatrics. https://doi.org/10.1186/s12887-026-07695-5

Image Credits: AI Generated

DOI: 10.1186/s12887-026-07695-5

Keywords: eye movement training, oculomotor function, balance, children, postural stability, eye-hand coordination, vestibulo-ocular reflex, saccades, smooth pursuit, home-based exercise, pilot study, pediatrics

The research focused on a task that cognitive neuroscientists have refined over decades: the interleaved pro-saccade and anti-saccade paradigm. In a pro-saccade trial, a participant simply looks toward a sudden visual target, an almost reflexive action governed by ancient circuitry linking the retina to the superior colliculus in the brainstem. In an anti-saccade trial, the instruction reverses: the participant must suppress the reflexive pull toward the target and instead look in the exact opposite direction. That act of suppression is anything but trivial. It depends on top-down executive control implemented by frontal-subcortical circuits—the same prefrontal networks that degrade in depression and that underpin planning, inhibition, and working memory. Because the reflexive and voluntary components of eye movement can be measured with millisecond precision, the task offers a window into executive function that is fast, non-invasive, and largely immune to the practice effects and cultural biases that plague paper-and-pencil tests.

The study enrolled 29 older adults diagnosed with late-life depression and 19 cognitively healthy controls of comparable age. Depression severity was quantified with the Geriatric Depression Scale-15, a widely used screening instrument, while global cognitive status was assessed with the Montreal Cognitive Assessment, or MoCA, a sensitive measure of mild cognitive impairment. Each participant then completed the interleaved saccade task while a high-speed video-based eye tracker recorded the trajectory, timing, and direction of every eye movement. The researchers extracted a rich set of measures: the rate of direction errors in anti-saccade trials, saccadic reaction times, the frequency of short-latency responses, the kinematic metrics of the movements themselves such as velocity and amplitude, and a less familiar quantity called voluntary override time, or VOT, which captures how long the executive system takes to override the reflexive response.

The headline finding was unambiguous. Older adults with late-life depression made significantly more direction errors on anti-saccade trials than the healthy controls did. In other words, when the task demanded that they suppress the automatic urge to glance at a flashing target, their eyes betrayed them more often. This is precisely the signature one would expect from weakened prefrontal inhibitory control, because the anti-saccade error rate is one of the most reliable behavioral indices of frontal-lobe integrity in the cognitive neuroscience literature. Importantly, the deficit was selective. The basic machinery of eye movement appeared intact: saccade metrics such as peak velocity and amplitude did not differ reliably between the groups, suggesting that the depression-related impairment lay not in the motor periphery or the brainstem reflex circuit itself but in the higher-order control system that decides whether the reflex should be allowed to run.

A second, subtler result added an intriguing twist. Short-latency pro-saccades—reflexive glances toward the target—were actually faster in the depressed group than in the controls. Rather than a general slowing, which clinicians often associate with depression in the form of psychomotor retardation, the eye-movement data revealed a pattern of disinhibition: the reflexive pathway fired more quickly and the voluntary brake applied less effectively. This combination of faster reflexes and weaker suppression points toward an imbalance in the competitive interaction between the superior colliculus, which generates saccade commands, and the frontal cortical networks that modulate them. In computational terms, the threshold for triggering a reflexive response appears lower while the top-down signal that raises that threshold appears weaker, a double hit that compounds executive failure.

Perhaps the most clinically significant finding emerged from correlations within the depressed group. MoCA scores, which index global cognitive performance, were significantly associated with both anti-saccade error rates and voluntary override time, meaning that patients whose eye movements showed the weakest executive control also scored lowest on the standard cognitive assessment. Yet depression severity, as measured by the GDS-15, showed no correlation with any of the oculomotor measures. This dissociation is important. It suggests that the saccade abnormalities track the cognitive dimension of late-life depression rather than the mood symptoms themselves, positioning the eye-tracking paradigm as a potential probe of the executive dysfunction that predicts poorer treatment outcomes, greater functional decline, and elevated risk of progression to dementia in this population.

The implications reach beyond the clinic. Late-life depression affects millions of older adults worldwide and is increasingly understood not merely as a mood disorder but as a condition with genuine neurobiological consequences, involving vascular injury, inflammation, and neurodegeneration in frontal-subcortical circuits. Executive dysfunction is one of its most disabling features, undermining medication adherence, financial decision-making, and the ability to benefit from psychotherapy. Yet because mood symptoms fluctuate and self-report is unreliable, the cognitive component often goes unrecognized until it has already compounded disability. A two-minute eye-tracking test that could be administered in a general practitioner’s office would offer a way to detect this component early, monitor it over time, and potentially identify which patients need closer neuropsychological follow-up.

The authors are careful to frame their results as preliminary. The sample sizes were modest, with 29 patients and 19 controls, and the study design was cross-sectional, capturing a single snapshot rather than tracking change over time. Larger longitudinal cohorts will be needed to establish whether saccade measures are reliable across repeated testing sessions, whether they predict clinical trajectories such as conversion to dementia, and whether they respond to treatment as depression remits. Questions also remain about how the measures perform in patients taking different classes of antidepressant medication, in those with coexisting medical illness, and in populations with different educational backgrounds. The researchers themselves state that further work is required to establish the reliability and clinical utility of saccade-based assessment in late-life depression.

Even so, the study adds to a growing movement in neuroscience and psychiatry toward behavioral measures that bypass self-report entirely. Eye movements occupy a privileged position in this effort because the circuits that control them are well mapped, their timing can be resolved to the millisecond, and the tasks that engage them are simple enough for frail or cognitively impaired patients to complete. The anti-saccade task in particular has a long pedigree as a probe of frontal function, having revealed inhibitory deficits in schizophrenia, Parkinson’s disease, attention deficit hyperactivity disorder, and normal aging. Extending it to late-life depression connects that literature to one of geriatric psychiatry’s most pressing clinical problems and demonstrates that a disorder of mood leaves measurable fingerprints on one of the body’s fastest and most automatic behaviors.

What makes the finding resonate is its elegance: the same neural machinery that lets a person resist an impulsive glance at a flashing light also lets them resist impulsive decisions, hold plans in mind, and steer attention where it needs to go. When that machinery falters in late-life depression, the failure shows up first where it can be measured most precisely—in the eyes. If larger studies confirm the reliability of these saccade-based markers, the humble eye movement could become a routine vital sign of executive health in aging, transforming how clinicians detect, track, and ultimately treat the cognitive shadow that follows depression into later life.

Subject of Research: Executive dysfunction in late-life depression assessed through saccadic eye-movement control

Article Title: Altered saccade control reveals executive dysfunction in late-life depression

Article References: Lee, Y.-T., Tai, Y.-H., Huang, L.-K., Chen, K.-Y., Chen, T.-L., Chen, C., & Wang, C.-A. (2026). Altered saccade control reveals executive dysfunction in late-life depression. BMC Geriatrics. https://doi.org/10.1186/s12877-026-08427-1

Image Credits: AI Generated

DOI: 10.1186/s12877-026-08427-1

Keywords: late-life depression, saccades, anti-saccade task, executive control, eye tracking, superior colliculus, geriatric psychiatry, MoCA, cognitive control, prefrontal cortex, voluntary override time, BMC Geriatrics