Glaucoma and biomechanics

Safa, Babak N.; Wong, Cydney A.; Ha, Jung‐Min; Ethier, C. Ross

doi:10.1097/icu.0000000000000829

Cited by 31 publications

(24 citation statements)

References 158 publications

(177 reference statements)

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“…Thus, our objective was to evaluate the biomechanical effects of NPP using a validated finite element (FE) modeling, a computational technique that allows efficient and flexible parametric investigation of the effects of mechanical loads on ocular tissues [16]–[22]. We focused on the ONH since it is an early and important site of neurological damage in glaucoma, and decreased ONH strain is likely beneficial for the treatment of glaucoma while increased strain of the ONH could be detrimental[3], [23], [24] [3], [23], [24]. Secondarily, we explored mechanical strains in the cornea induced by NPP, which is directly loaded by the application of NPP.…”

Section: Introductionmentioning

confidence: 99%

The Effects of Negative Periocular Pressure on Biomechanics of the Optic Nerve Head and Cornea: A Computational Modeling Study

Safa

Bleeker

Berdahl

et al. 2022

Preprint

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PurposeTo evaluate the effects of negative periocular pressure (NPP), and concomitant intraocular pressure (IOP) lowering, on the biomechanics of the optic nerve head (ONH) and cornea.MethodsWe developed a validated finite element (FE) model of the eye to compute tissue biomechanical strains induced in response to NPP delivered using the Multi-Pressure Dial (MPD) system. The model was informed by clinical measurements of IOP lowering and was based on published tissue properties. We also conducted sensitivity analyses by changing pressure loads and tissue properties.ResultsApplication of -7.9 mmHg NPP decreased strain magnitudes in the ONH by c. 50% while increasing corneal strain magnitudes by c. 25%. Comparatively, a similar increase in corneal strain was predicted to occur due to an increase in IOP of 4 mmHg. Sensitivity studies indicated that NPP lowers strain in the ONH by reducing IOP and that these effects persisted over a range of tissue stiffnesses and spatial distributions of NPP.ConclusionsNPP is predicted to considerably decrease ONH strain magnitudes. It also increases corneal strain but to an extent expected to be clinically insignificant. Thus, using NPP to lower IOP and hence decrease ONH mechanical strain is likely biomechanically beneficial for glaucoma patients.Translational RelevanceThis study provides the first description of how NPP affects ONH biomechanics and explains the underlying mechanism of ONH strain reduction. It complements current empirical knowledge about the MPD system and guides future studies of NPP as a treatment for glaucoma.

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Section: Introductionmentioning

confidence: 99%

The Effects of Negative Periocular Pressure on Biomechanics of the Optic Nerve Head and Cornea: A Computational Modeling Study

Safa

Bleeker

Berdahl

et al. 2022

Preprint

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“…The LC inserts and anchors itself into the ppScl which provides substantial support to counteract IOP [ 3 , 4 , 5 ]. In fact, the ppScl may experience the greatest amount of strain in response to elevated IOP [ 6 , 7 ]. The LC and ppScl also receive counteracting pressure from the post-laminar CSF [ 8 ].…”

Section: Remodeling Response In Aging and Glaucomamentioning

confidence: 99%

Remodeling of the Lamina Cribrosa: Mechanisms and Potential Therapeutic Approaches for Glaucoma

Strickland

Garner

Gross

et al. 2022

IJMS

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Glaucomatous optic neuropathy is the leading cause of irreversible blindness in the world. The chronic disease is characterized by optic nerve degeneration and vision field loss. The reduction of intraocular pressure remains the only proven glaucoma treatment, but it does not prevent further neurodegeneration. There are three major classes of cells in the human optic nerve head (ONH): lamina cribrosa (LC) cells, glial cells, and scleral fibroblasts. These cells provide support for the LC which is essential to maintain healthy retinal ganglion cell (RGC) axons. All these cells demonstrate responses to glaucomatous conditions through extracellular matrix remodeling. Therefore, investigations into alternative therapies that alter the characteristic remodeling response of the ONH to enhance the survival of RGC axons are prevalent. Understanding major remodeling pathways in the ONH may be key to developing targeted therapies that reduce deleterious remodeling.

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“…И з в е с т н о , что у р о в е н ь В ГД т е с н о в з а и м о с в я з а н с б и о м е х ан и ч е ск и м и св о й ств ам и к о р н е о с к л е р а л ь н о й о б о л о ч к и гл аза [11][12][13]. У стан о вл ен о , что по м ер е п р о гр ес-Россиискии офтальмологический журнал.…”

Section: Conclusion the Macro-and Microelement Imbalance O F The Scle...unclassified

Trace elements composition of the scleral shell of the eye in various forms of glaucoma

Arutyunyan

Iomdina

Morozova

et al. 2022

Rossijskij oftalʹmologičeskij žurnal

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Purpose: a comparative study of the elemental composition of scleral biopsy specimens from patients with various clinical forms of glaucoma. Material and methods. 44 patients aged 79.5 ± 2.5 were divided into three groups depending on the form of glaucoma: 16 patients with primary open-angle glaucoma (POAG) (group 1); 13 patients with normal tension glaucoma (NTG) (group 2); 15 patients with pseudoexfoliative glaucoma (PEG) (group 3). For elemental analysis, we used scleral biopsies obtained during planned surgical treatment of glaucoma (non-penetrating sinus trabeculectomy). Scleral fragments of 14 donor eyes with no history of glaucoma served as controls. The concentration of macroelements K, Mg, Ca, and Fe was determined using inductively coupled plasma atomic emission spectrometry (ICP-AES, Agilent ICP-AES 720 ES, USA), while microelement concentration (Zn, Cu, Al, Mn) was measured using inductively coupled plasma mass spectrometry (ICP-MS, Bruker ICP-M S 820, Germany). Results. In all forms of glaucoma, scleral samples showed a varying increase in the content of such elements as Zn, Fe, Mg, AL, Ca, K. The highest content of Zn and Fe was found in the scleral tissue of patients with NTG, the difference with the control (p = 0.0001 andp = 0.0003) and with POAG (p = 0.0002, p = 0.0001) being highly significant. The difference between the content of Zn in scleral biopsies of patients with POAG and PEG was also statistically significant (p = 0.0002), whilst no significant difference in Fe content in the sclera (p = 0.69) was found between POAG and PEG Higher Mg concentrations as compared to the control were found in NTG (p = 0.00014) and POAG (p = 0.00002).Patients with POAG (p = 0.0005) and PEG (p = 0.00022) showed the highest accumulation of Ca in the sclera. No differences were found in Mg content of scleral biopsies between patients with NTG and POAG (p = 1.0), while the level of Ca in POAG (p = 0.02) and PEG (p = 0.00001) was significantly higher than in NTG. A significantly lower content of Cu was found in the sclera samples of patients with NTG (p = 0.022), POAG (p = 0.004) and PEG (p = 0.00004) as compared to the control, as well as a reduced content of Mn in POAG (p = 0.00003) and PEG (p = 0.0012). Contrarywise, NTG patients showed an increased content of Mn (p = 0.000003). No differences were found in the Cu content between the sclera of patients with NTG and POAG (p = 0.47), while Cu level in PEG was significantly lower than in POAG (p = 0.034) and NTG (p = 0.013). Conclusion. The macro- and microelement imbalance of the sclera of the eyes with different forms of glaucoma indicates differences in their pathogenesis. This can be the reason for the different severity of disorders of collagen biosynthesis and the formation of cross-links in the connective tissue structures of the sclera, as well as the varying degree changes in the hydrodynamics of the intraocular fluid, which on the whole can affect the level of intraocular pressure and the pattern of glaucoma development.

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Glaucoma and biomechanics

Cited by 31 publications

References 158 publications

The Effects of Negative Periocular Pressure on Biomechanics of the Optic Nerve Head and Cornea: A Computational Modeling Study

The Effects of Negative Periocular Pressure on Biomechanics of the Optic Nerve Head and Cornea: A Computational Modeling Study

Remodeling of the Lamina Cribrosa: Mechanisms and Potential Therapeutic Approaches for Glaucoma

Trace elements composition of the scleral shell of the eye in various forms of glaucoma

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