Publishing date: November 2023
Author(s): Thanadet Chuangsuwanich (1,2), Tin A Tun (3,4), Fabian A Braeu (2,4), Clarice H Y Yeoh (1), Rachel S Chong (4), Xiaofei Wang (5), Tin Aung (1,3,4), Quan V Hoang (1,3,4,6), Michaël J A Girard (2,3,7)
1 Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
2 Ophthalmic Engineering & Innovation Laboratory, Singapore Eye Research Institute, Singapore National Eye Centre, Singapore.
3 Eye-ACP, Duke-NUS Medical School, Singapore, Singapore.
4 Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.
5 Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, School of Engineering Medicine, Beihang University, Beijing, China.
6 Department of Ophthalmology, Columbia University, New York, New York, United States.
7 Institute for Molecular and Clinical Ophthalmology, Basel, Switzerland.
PURPOSE: The purpose of this study was to assess optic nerve head (ONH) deformations following acute intraocular pressure (IOP) elevations and horizontal eye movements in control eyes, highly myopic (HM) eyes, HM eyes with glaucoma (HMG), and eyes with pathologic myopia (PM) alone or PM with staphyloma (PM + S).
METHODS: We studied 282 eyes, comprising of 99 controls (between +2.75 and -2.75 diopters), 51 HM (< -5 diopters), 35 HMG, 21 PM, and 75 PM + S eyes. For each eye, we imaged the ONH using spectral-domain optical coherence tomography (OCT) under the following conditions: (1) primary gaze, (2) 20 degrees adduction, (3) 20 degrees abduction, and (4) primary gaze with acute IOP elevation (to ∼35 mm Hg) achieved through ophthalmodynamometry. We then computed IOP- and gaze-induced ONH displacements and effective strains. Effective strains were compared across groups.
RESULTS: Under IOP elevation, we found that HM eyes exhibited significantly lower strains (3.9 ± 2.4%) than PM eyes (6.9 ± 5.0%, P < 0.001), HMG eyes (4.7 ± 1.8%, P = 0.04), and PM + S eyes (7.0 ± 5.2%, P < 0.001). Under adduction, we found that HM eyes exhibited significantly lower strains (4.8% ± 2.7%) than PM + S eyes (6.0 ± 3.1%, P = 0.02). We also found that eyes with higher axial length were associated with higher strains.
CONCLUSIONS: Our study revealed that eyes with HMG experienced significantly greater strains under IOP compared to eyes with HM. Furthermore, eyes with PM + S had the highest strains on the ONH of all groups.
Invest Ophthalmol Vis Sci. 2023 Aug 1;64(11):12. doi: 10.1167/iovs.64.11.12.
PMID: 37552032 PMCID: PMC10411647 DOI: 10.1167/iovs.64.11.12
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