IOP-induced regional displacements in the optic nerve head and correlation with peripapillary sclera thickness

Ma, Yanhui; Kwok, Sunny; Sun, Jian; Pan, Xueliang; Pavlatos, Elias; Clayson, Keyton; Hazen, Nicholas; Li, Jun

doi:10.1016/j.exer.2020.108202

Cited by 14 publications

(12 citation statements)

References 46 publications

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“…Based on computational models representing generic ONH geometry and material properties ( 8 ), higher sclera stiffness was associated with less deformation in ONH tissues. On the other hand, mechanical insult has been hypothesized as an initiating factor and a driving force in the disease process of glaucoma ( 43 , 44 ), suggesting more ONH deformation may be related to more glaucomatous axonal damage. Lower ocular rigidity was found to be positively correlated to greater glaucomatous damage represented by ganglion cell complex, retinal nerve fiber layer thicknesses, and neuroretinal rim area ( 45 ).…”

Section: Discussionmentioning

confidence: 99%

Non-invasive Clinical Measurement of Ocular Rigidity and Comparison to Biomechanical and Morphological Parameters in Glaucomatous and Healthy Subjects

Moroi

Roberts

2021

Front. Med.

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Purpose: To assess ocular rigidity using dynamic optical coherence tomography (OCT) videos in glaucomatous and healthy subjects, and to evaluate how ocular rigidity correlates with biomechanical and morphological characteristics of the human eye.Methods: Ocular rigidity was calculated using Friedenwald's empirical equation which estimates the change in intraocular pressure (IOP) produced by volumetric changes of the eye due to choroidal pulsations with each heartbeat. High-speed OCT video was utilized to non-invasively measure changes in choroidal volume through time-series analysis. A control-case study design was based on 23 healthy controls and 6 glaucoma cases. Multiple diagnostic modalities were performed during the same visit including Spectralis OCT for nerve head video, Pascal Dynamic Contour Tonometry for IOP and ocular pulse amplitude (OPA) measurement, Corvis ST for measuring dynamic biomechanical response, and Pentacam for morphological characterization.Results: Combining glaucoma and healthy cohorts (n = 29), there were negative correlations between ocular rigidity and axial length (Pearson R = −0.53, p = 0.003), and between ocular rigidity and anterior chamber volume (R = −0.64, p = 0.0002). There was a stronger positive correlation of ocular rigidity and scleral stiffness (i.e., stiffness parameter at the highest concavity [SP-HC]) (R = 0.62, p = 0.0005) compared to ocular rigidity and corneal stiffness (i.e., stiffness parameter at the first applanation [SP-A1]) (R = 0.41, p = 0.033). In addition, there was a positive correlation between ocular rigidity and the static pressure-volume ratio (P/V ratio) (R = 0.72, p < 0.0001).Conclusions: Ocular rigidity was non-invasively assessed using OCT video and OPA in a clinic setting. The significant correlation of ocular rigidity with biomechanical parameters, SP-HC and P/V ratio, demonstrated the validity of the ocular rigidity measurement. Ocular rigidity is driven to a greater extent by scleral stiffness than corneal stiffness. These in vivo methods offer an important approach to investigate the role of ocular biomechanics in glaucoma.

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Section: Discussionmentioning

confidence: 99%

Non-invasive Clinical Measurement of Ocular Rigidity and Comparison to Biomechanical and Morphological Parameters in Glaucomatous and Healthy Subjects

Moroi

Roberts

2021

Front. Med.

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“…In addition, Jin et al [ 53 ] developed a FE model of a normal eye, and predicted ocular pulse amplitude, choroidal expansion could affect the biomechanics of ONH during the cardiac cycle. Ma et al [ 54 ] investigated the correlation between IOP-induced local displacement of the ONH and the thickness of the peripapillary sclera, the results suggest that the greater backward movement of ONH relative to the surrounding tissues, the thinner peripapillary tissue, and also the LC may play a major role in preventing excessive backward displacement of ONH during acute elevated IOP.…”

Section: In Vitro Biomechanical Study Methods Of Eye Tissuementioning

confidence: 99%

Biomechanical analysis of ocular diseases and its in vitro study methods

Zhao

Yan

et al. 2022

BioMed Eng OnLine

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Ocular diseases are closely related to the physiological changes in the eye sphere and its contents. Using biomechanical methods to explore the relationship between the structure and function of ocular tissue is beneficial to reveal the pathological processes. Studying the pathogenesis of various ocular diseases will be helpful for the diagnosis and treatment of ocular diseases. We provide a critical review of recent biomechanical analysis of ocular diseases including glaucoma, high myopia, and diabetes. And try to summarize the research about the biomechanical changes in ocular tissues (e.g., optic nerve head, sclera, cornea, etc.) associated with those diseases. The methods of ocular biomechanics research in vitro in recent years are also reviewed, including the measurement of biomechanics by ophthalmic equipment, finite element modeling, and biomechanical analysis methods. And the preparation and application of microfluidic eye chips that emerged in recent years were summarized. It provides new inspiration and opportunity for the pathogenesis of eye diseases and personalized and precise treatment.

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“…Various methods have been used to analyze biomechanical properties of the ONH and PPS and their effects on glaucoma development. These include computational models, 13,14,66–82 experimentally induced ocular hypertension/glaucoma in animals, 45,46,83–92 and patient cadaveric/enucleated eyes 56,60,93–102 . Computational studies suggested that stiffness of the sclera, radius of the eye, stiffness of the LC, IOP, and thickness of the sclera, in order, were found to be the largest influential factors on the biomechanical response of the ONH to IOP changes 75 .…”

Section: Studies On Biomechanical Properties Of the Onh And The Scleramentioning

confidence: 99%

Biomechanics of the optic nerve head and sclera in canine glaucoma: A brief review

Park

Komàromy

2021

Veterinary Ophthalmology

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Glaucoma is a leading cause of irreversible blindness, a progressive optic neuropathy with retinal ganglion cell (RGC) death beginning in the optic nerve head (ONH). A primary risk factor for developing glaucoma is elevated intraocular pressure (IOP). Reducing IOP is the only treatment proven to be effective at delaying disease progression. Nevertheless, even when patients have their IOP reduced, the majority of them continue to lose vision. There are, in both humans and dogs, significant interindividual variabilities in susceptibilities to IOP‐induced optic nerve damage. Vision loss progresses much more slowly in Beagles with open‐angle glaucoma (OAG) caused by ADAMTS10 mutation. This can be attributed to the mutation‐related altered ocular biomechanical properties. The principal site of optic nerve (ON) damage in glaucoma is the ONH. It is suggested that the biomechanical properties of the ONH and the surrounding peripapillary sclera (PPS) contribute to glaucoma development and progression. As far as the beneficial biomechanical properties of the ONH and PPS for a decreased susceptibility and slow progression of glaucoma, data are inconsistent and conflicting. Recent biomechanical studies on beagles with ADAMTS10 mutation demonstrated that the mutant dogs have mechanically weak posterior sclera. This weakness was associated with a reduced collagen density and a lower proportion of insoluble collagen. These changes, observed before glaucoma development, were considered intrinsic characteristics caused by the mutation rather than a secondary effect of IOP elevation. Further studies of ADAMTS10‐OAG may elucidate the effects of altered biomechanical properties of ONH and PPS in determining the glaucoma progression.

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IOP-induced regional displacements in the optic nerve head and correlation with peripapillary sclera thickness

Cited by 14 publications

References 46 publications

Non-invasive Clinical Measurement of Ocular Rigidity and Comparison to Biomechanical and Morphological Parameters in Glaucomatous and Healthy Subjects

Non-invasive Clinical Measurement of Ocular Rigidity and Comparison to Biomechanical and Morphological Parameters in Glaucomatous and Healthy Subjects

Biomechanical analysis of ocular diseases and its in vitro study methods

Biomechanics of the optic nerve head and sclera in canine glaucoma: A brief review

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