Related Experiment Video
Updated: Jun 18, 2026

Using Eye-tracking to Assess the Relative Importance of Visual and Vestibular Input to Subcortical Motion Processing in the Roll Plane
Published on: August 22, 2025
Age-related changes in the orbital pulley array of older Japanese adults with acquired exotropia
Reika Kono1,2, Ichiro Hamasaki3, Fumiko Kishimoto4
1Department of Ophthalmology,, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama City, Okayama, 700-8558, Japan. reikak@icloud.com.
Purpose:
To evaluate age-related changes in the orbital pulley array using magnetic resonance imaging (MRI) in older Japanese adults with acquired exotropia (XT) compared with young healthy participants (YHP).
Methods:
In this retrospective cross-sectional case series, MRI images of 30 eyes from fifteen patients (age ≥ 60 years) with distance XT and no high myopia were compared with those of 14 eyes from seven YHP. Rectus muscle (RM) pulley positions relative to the globe center were assessed. The lateral rectus muscle-superior rectus (LR-SR) band was evaluated for rupture.
Results:
Mean age of patients with XT was 73.7 ± 5.5 years. Compared with YHP, patients with XT showed significant inferior displacement of the lateral rectus (LR) pulley (-3.6 ± 1.2 mm vs. - 2.0 ± 1.1 mm, p < 0.01) and temporal displacement of the superior rectus (SR) pulley (-0.4 ± 1.2 mm vs. - 1.6 ± 0.8 mm, p < 0.01). No significant differences were observed in medial rectus or inferior rectus pulley positions. Inferior LR pulley displacement correlated with inferior SR pulley displacement (r = 0.41, p = 0.03), whereas no significant relationship was observed between LR pulley position and MR or IR pulley position. Rupture of the LR-SR band was observed in 24 orbits (80.0%).
Conclusion:
Older Japanese adults with XT exhibit localized pulley displacement and LR-SR band rupture. These structural changes differ from the global sagging observed in sagging eye syndrome and may contribute to the pathogenesis of acquired exotropia in older adults.
Related Concept Videos
Accessory Structures of the Eye
Muscles of the Eye
Extraocular Muscles
The six extraocular muscles surround the eyeball and control its movements. They are responsible for a wide range of eye motions, including looking up, down, left, right, and rotating...
Mechanism of Ciliary Motion
The cilia are made up of microtubules in a 9+2 arrangement, with nine microtubule doublet ring bundles, surrounding a pair of central singlet microtubule bundles. The doublet microtubule bundles are...
Mechanism of Ciliary Motion
The cilia are made up of microtubules in a 9+2 arrangement, with nine microtubule doublet ring bundles, surrounding a pair of central singlet microtubule bundles. The doublet microtubule bundles are...
Eccentric Axial Loading in a Plane of Symmetry
Changes in the Appendicular Skeleton with Age
Initially, the limb buds consist of a core of mesenchyme covered by a layer of ectoderm. The ectoderm at the end of the limb bud thickens to form a narrow crest called the apical ectodermal ridge. This ridge stimulates the underlying...

