Purpose: To measure lamina cribrosa (LC) strains (deformations) following abduction and adduction in healthy subjects and to compare them with those resulting from a relatively high acute intraocular pressure (IOP) elevation.
Methods: A total of 16 eyes from 8 healthy subjects were included. Among the 16 eyes, 11 had peripapillary atrophy (PPA). For each subject, both optic nerve heads (ONHs) were imaged using optical coherence tomography (OCT) at baseline (twice), in different gaze positions (adduction and abduction of 20°) and following an acute IOP elevation of approximately 20 mm Hg from baseline (via ophthalmodynamometry). Strains of LC for all loading scenarios were mapped using a three-dimensional tracking algorithm.
Results: In all 16 eyes, LC strains induced by adduction and abduction were 5.83% ± 3.78% and 3.93% ± 2.57%, respectively, and both significantly higher than the control strains measured from the repeated baseline acquisitions (P < 0.01). Strains of LC in adduction were on average higher than those in abduction, but the difference was not statistically significant (P = 0.07). Strains of LC induced by IOP elevations (on average 21.13 ± 7.61 mm Hg) were 6.41% ± 3.21% and significantly higher than the control strains (P < 0.0005). Gaze-induced LC strains in the PPA group were on average larger than those in the non-PPA group; however, the relationship was not statistically significant.
Conclusions: Our results confirm that horizontal eye movements generate significant ONH strains, which is consistent with our previous estimations using finite element analysis. Further studies are needed to explore a possible link between ONH strains induced by eye movements and axonal loss in optic neuropathies.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1167/iovs.16-20560 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Horizontal Gaze Tolerance and Its Effects on Visual Sensitivity in Glaucoma.
Invest Ophthalmol Vis Sci
January 2025
Department of Ophthalmology, Saitama Medical University, Saitama, Japan.
Purpose: This study evaluates the effect of 6° horizontal gaze tolerance on visual field mean sensitivity (MS) in patients with glaucoma using a binocular head-mounted automated perimeter, following findings of structural changes in the posterior globe from magnetic resonance imaging and optical coherence tomography.
Methods: In this cross-sectional study, a total of 161 eyes (85 primary open-angle glaucoma [POAG] and 76 healthy) from 117 participants were included. Logistic regression and 1:1 matched analysis assessed the propensity score for glaucoma and healthy eyes, considering age, sex, and axial length as confounders.
Response preparation is accomplished by gradual accumulation in neural activity until a threshold is reached. In humans, such a preparatory signal, referred to as the lateralized readiness potential, can be observed in the EEG over sensorimotor cortical areas before execution of a voluntary movement. Although well-described for manual movements, less is known about preparatory EEG potentials for saccadic eye movements in humans and nonhuman primates.
View Article and Find Full Text PDFAbnormal eye movements occur early in the course of disease in many ataxias. However, clinical assessments of oculomotor function lack precision, limiting sensitivity for measuring progression and the ability to detect subtle early signs. Quantitative assessment of eye movements during everyday behaviors such as reading has potential to overcome these limitations and produce functionally relevant measures.
View Article and Find Full Text PDFPoor fixation stability does not account for motion perception deficits in amblyopia.
Sci Rep
January 2025
Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, BC, Canada.
People with amblyopia show deficits in global motion perception, especially at slow speeds. These observers are also known to have unstable fixation when viewing stationary fixation targets, relative to healthy controls. It is possible that poor fixation stability during motion viewing interferes with the fidelity of the input to motion-sensitive neurons in visual cortex.
View Article and Find Full Text PDFApathy in Alzheimer's disease: Eye movements characteristics and neurostructural basis.
J Affect Disord
January 2025
Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China; Center for Cognitive Neurology, Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China; China National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China. Electronic address:
Background: We sought to evaluate the characteristics of eye movements in Alzheimer's disease (AD) patients with apathy (AD-A) and their ability to identify AD-A and explore the shared neurostructure of eye movements and apathy.
Methods: Total 32 normal controls, 36 AD-A and 72 AD with no apathy (AD-NA) patients were recruited. Parameters of smooth pursuit, fixation, prosaccade and antisaccade were compared among the three groups.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!