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ORIGINAL RESEARCH article
Front. Neurol.
Sec. Neuro-Ophthalmology
Volume 16 - 2025 |
doi: 10.3389/fneur.2025.1493418
A video-oculography study of fixation instability in Myasthenia Gravis
Provisionally accepted- 1 Monash University, Melbourne, Australia
- 2 Alfred Health, Melbourne, Australia
Introduction: Myasthenia Gravis (MG) is an autoimmune disease that causes extraocular muscle weakness in up to 70-85% of patients, which can impact quality of life. Current diagnostic measures are not very sensitive for ocular MG. This study aims to compare fixation instability (inability to maintain gaze on a target) in patients with MG with control participants using video-oculography.Methods: A prospective study of 20 age and sex matched MG and control participants as performed using a novel protocol with the Eyelink 1000 plus ©. Bivariate contour ellipse area (BCEA) analysis, number of fixations at target and percentage of dwell time of fixations in target interest area (IA) were calculated. Intereye (right vs left) comparison was performed with paired T-tests and inter-group (MG vs control) comparisons performed with independent samples testing.Results: There were no inter-eye differences in the BCEAs of control eyes or MG eyes. However, BCEAs were larger in both right (RE) and left (LE) eyes of MG patients compared to controls in the right (RE p=0.029, LE p=0.033), left (RE p=0.006, LE p=0.004), up(RE p=0.009, LE p=0.018), down (RE p=0.006, LE p=0.006) gaze hold. The total mean sum of gaze hold fixations in all directions were greater in MG than control participants (354 ± 139 vs 249±135, p= 0.020), with horizontal gaze holds showing greater differences than vertical gaze holds (p=0.007 vs p=0.097). Percentage dwell time in target IA was lower in MG patients but this only reached significance in right gaze hold (p=0.003).MG patients showed greater BCEA values and refixations and lower target IA percentages of dwell time in during gaze hold compared to control participants, suggesting extraocular neuromuscular junction instability and fatigue. Interestingly, there were no significant inter-eye differences in the MG participants. This study is limited by a small number of patients but adds to the current literature exploring video-oculography in MG patients as novel diagnostic tool. Further studies are recommended for translation into clinical practice.
Keywords: Myasthenia, Videooculograph(y) (VOG), Fixation instability, Neuromuscular Junction, Ocular myasthenia
Received: 09 Sep 2024; Accepted: 29 Jan 2025.
Copyright: © 2025 Nguyen, Clough, Fielding and White. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Elle Minh Ngoc Le Nguyen, Monash University, Melbourne, Australia
Owen B White, Monash University, Melbourne, Australia
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