Purpose To determine if the stress of normal eye movements results in gaze-induced globe deformations, vitreous chamber axial length and vitreous chamber axial volume (VCAV) change in highly myopic eyes.
Methods A prospective imaging study was performed on 82 eyes of 43 patients with high myopia (>27 mm of axial length) with a clinical diagnosis of staphyloma. Three-dimensional MRI scans were acquired while subjects gazed in five directions (primary, nasal, temporal, superior and inferior). Surface renderings were generated, and a processing pipeline was created to automate alignment of the eye and to measure VCAV within 5.5 mm of the visual axis for each eye in every gaze. The degree of gaze-induced globe deformation was determined by calculating the Dice coefficient to assess the degree of overlap of the sclera at each eccentric gaze with that found in primary gaze. Each eccentric gaze VCAV was compared to VCAV in primary gaze using a fixed-effects regression allowing for subject-specific and eye-specific effects.
Results The Dice coefficient showed significant gaze-induced eye shape changes in all gazes (all p<0.0001). There were no statistically significant gaze-induced VCAV changes when comparing primary gaze to nasal, temporal or upgaze. However, when changing from primary to downgaze, VCAV was increased by +4.79 mm3 (p=0.002, 95% CI 1.71 to 7.86).
Conclusion Significant gaze-induced globe deformation was noted in all gazes, but a reversible, instantaneous VCAV increase occurred only in downgaze, which is consistent with studies supporting the association of environmental factors such as near work with myopia development and progression.
- Eye (Globe)
- Sclera and Episclera
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Contributors Design of the study: QVH, JG. Conduct of the study: QVH, SC, DJGY, LAY, KBF, JG. Collection of the data: QVH, SC, LAY, KBF, JG. Management of the data: QVH, DJGY, JG. Analysis of the data and interpretation of the data: QVH, JG. Preparation of the manuscript: QVH, DJGY, JG. Review of the manuscript and approval of the manuscript: QVH, SC, DJGY, LAY, KBF, JG.
Funding This publication was supported in part by Career Development Awards from Research to Prevent Blindness (QVH), K08 Grant (QVH, 1 K08 EY023595, National Eye Institute, NIH) the Louis V. Gerstner Jr Scholars Program (QVH), Clinician Scientist Award (QVH, CSA-INVMay0011, National Medical Research Council, Singapore), philanthropic donation from John Cushman (QVH) and The Macula Foundation, New York, NY (LAY). The funding organisations had no role in the design or conduct of this research.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available upon reasonable request.
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