Aug 2026· Investigative Ophthalmology and Visual Science· Vol 67· 0 citations· 22 references
Medicine
TL;DR
Video-based eye tracking revealed frequent conjugate movements during vergence stimulation in ACE, suggesting restoration of coordinated binocular motor control after medial rectus recession surgery.
Abstract
Purpose To quantitatively evaluate vergence-related eye movements in acquired comitant esotropia (ACE) using video-based eye tracking and to characterize abnormal movement patterns and their postoperative changes. Methods We studied 46 patients with ACE (mean age, 24.3 years) who underwent unilateral or bilateral medial rectus recession. Binocular gaze was recorded at 300 Hz (Tobii Pro Spectrum) while participants alternately fixated every 5 seconds on a near target (30 cm) and a far target (60 cm). Stable amplitude was the difference between the mean near- and far-target gaze angles in the 3- to 4-second period after each target step. Eye movements were classified as conjugate or vergence according to the direction of stable amplitude in each eye. Saccadic onset, offset, and postsaccadic stabilization metrics were extracted. Statistical analyses included logistic regression and Wilcoxon signed-rank tests. Results Despite vergence stimulation, 26 patients (56.5%) exhibited conjugate movements, whereas 20 patients (43.5%) showed vergence movements. Conjugate movements were associated with a larger absolute stable amplitude of the fixating eye, larger absolute saccadic amplitudes in both eyes, and a smaller interocular difference in saccadic amplitude (fixating – non-fixating; all P < 0.05). In addition, interocular differences were observed in stabilization time and amplitude, particularly in the vergence group. Postoperatively, conjugate movements decreased markedly, as 81.8% of patients (18/22) demonstrated vergence movements at 1 month, and 92.3% (12/13) at ≥3 months. Conclusions Video-based eye tracking revealed frequent conjugate movements during vergence stimulation in ACE. After medial rectus recession surgery, vergence responses increased substantially, suggesting restoration of coordinated binocular motor control.
BACKGROUND: Quantitative assessment of vestibular nerve activity has been difficult with conventional electrophysiological techniques. This study aimed to develop a novel method combining galvanic vestibular stimulation (GVS) with 3-dimensional video-oculography (3D-VOG) to evaluate vestibular function noninvasively.
METHODS: Eye movements were recorded from healthy individuals using a high-resolution infrared VOG system (yVOG, Yamaguchi University). Bipolar GVS was applied bilaterally over the mastoid processes with various current intensities (0.5-2.0 mA) and polarities. Horizontal, vertical, and torsional eye-movement components were extracted and analyzed in relation to stimulus parameters.
RESULTS: Torsional nystagmus amplitude and slow-phase velocity increased proportionally with stimulus intensity and reversed with polarity. Healthy participants exhibited symmetric responses. The induced eye-movement responses showed reproducible polarity- and intensity-dependent characteristics.
CONCLUSION: This study demonstrates that GVS-VOG provides a direct, reproducible, and noninvasive means of evaluating vestibular nerve function through eye movement analysis. The method may complement existing vestibular function tests in future clinical applications. Galvanic vestibular stimulation-video-oculography also offers utility in both research and clinical settings by linking physiological mechanisms with observable oculomotor responses. This approach holds promise as a diagnostic tool for vestibular disorders, especially when conventional tests yield inconclusive results.
Yosuke Okinaka, Makoto Hashimoto, J. Tsuda et al.· The journal of international...· 0 citations
This study demonstrates the safety and efficacy of EMAA in the rehabilitation of vergence disorders, combining the use of virtual reality (VR) and eye tracking.
A. Brodin, P. Fantou, A. Persillon et al.· Journal Francais d'Ophtalmol...· 0 citations
Purpose To investigate the eye movement pattern across different speeds during clinical dynamic visual acuity (DVA) tests and their relationship with dynamic visual performance. Methods Twenty young adults with normal or corrected-to-normal visual acuity underwent clinical DVA tests at 20, 40, 60, and 80 degrees per second (dps). Eye movement was recorded using a table-mounted eye tracker. Smooth pursuit- and saccade-related parameters were calculated from the gaze trace, and the relationships between eye movement parameters and dynamic visual performance were analyzed. Results DVA was significantly better at 20 dps than at higher speeds (p < 0.05 for all comparisons). Eye movement patterns and parameters varied with target velocity, as smooth pursuit dominated at low speeds and saccades became more prominent at high speeds. At 20 dps, DVA correlated negatively with saccade displacement (r = −0.523, p = 0.022) and displacement per saccade (r = −0.528, p = 0.020). During the DVA test at 80 dps, positive correlations emerged between DVA and saccade period (r = 0.521, p = 0.022), duration (r = 0.500, p = 0.029), and displacement (r = 0.483, p = 0.036). Increased saccade episode (β = 0.540, p < 0.001) and time (β = 27,333, p < 0.001) were associated with greater odds of identification error at 20 dps. At 80 dps, higher smooth pursuit velocity was associated with increased odds of identification error (β = 0.030, p = 0.016). Conclusion Eye movement strategies adapt dynamically to target speed. Quick and efficient saccades support improved dynamic visual performance, although high-amplitude saccades and pursuit velocity disrupted tracking at high speeds. These findings offer insights for optimizing clinical DVA tests and enhancing the clinical utility of DVA as a functional vision indicator.
There was a significant relationship between convergence fusion range and stereoacuity measured using the Frisby and Real Depth stereo tests in this population of adults with normal binocular single vision.
Rani Ibrahim Bahho, M. Ilango, A. French et al.· Strabismus· 0 citations
Persistent postural‐perceptual dizziness (PPPD) patients with visual dependency rely more on visual cues and may have altered oculomotor responses to visual motion. This study examined early eye movement responses to large‐field motion stimuli—the ocular following responses (OFRs)—in 30 PPPD patients and 29 healthy controls. Participants viewed horizontal motion in peripheral and/or central visual fields while eye movements were recorded. OFR velocity 200 ms after stimulus onset and suppression efficacy were analyzed across four central field sizes from 5° to 42° radius. Both groups exhibited strong OFRs to stimuli in the central visual field that increased with the size of the stimulation area. When the central visual field was stationary and the surrounding area moved, patients showed significantly higher eye velocity than controls. Both groups could partially suppress OFRs, but healthy controls were more effective at suppressing eye movements during peripheral stimulation. Patients also showed greater visual dependency on the dynamic subjective visual vertical (2.2° vs. 1.2°), which correlated with OFR magnitude. Overall, PPPD patients were less able to keep their eyes still during peripheral visual motion, producing greater retinal slip and disrupting volitional fixation—an abnormality that may contribute to dizziness and discomfort in visually complex environments.
Vergil V Mavrodiev, Konrad P Weber, Christopher J Bockisch et al.· Annals of the New York Acade...· 0 citations
Alignment heat maps allow intuitive visualization of selective strabismus surgical strategies treating varied incomitance in SO palsy, reflecting progressive improvement in alignment when surgery includes IO recession.
Qi Wei, Thomas Chang, Andrew Ryan et al.· Strabismus· 0 citations