scholarly journals Image-Based Modeling of Optic Nerve Head Mechanics Following Lumbar Puncture

2017 ◽  
Author(s):  
Junfei Tong ◽  
Deepta Ghate ◽  
Sachin Kedar ◽  
Linxia Gu
Keyword(s):  
Optic Nerve ◽  
Lumbar Puncture ◽  
Optic Nerve Head ◽  
Computational Models ◽  
Cell Damage ◽  
Open Angle Glaucoma ◽  
Element Model ◽  
Lamina Cribrosa ◽  
Image Based Modeling

Biomechanics of optic nerve head (ONH) has attracted increasing attention in recent years due to its association with ganglion cell damage and tissue remodeling resulted vision impairments [1, 2]. The ONH is exposed to both intraocular pressure (IOP) and intracranial pressure (ICP), separated by the lamina cribrosa (LC) which is regarded as the primary site of axonal injury in glaucoma[3]. The elevated IOP was widely acknowledged as a major risk factor for glaucoma. However, a large number of glaucoma patients never have an increase in IOP [4]. In studies that have looked at lumbar puncture (LP) data, patients with open-angle glaucoma were found to have lower ICPs than non-glaucomatous controls[5]. It suggests that higher translaminar pressure difference across the LC rather than IOP alone may have an important role in the pathogenesis of ONH damage. There were few computational models had been established to investigate the ICP’s role on ONH, such as Ethier et al. found elevated ICP could induce decreased strain within LC using finite element model[6]. However, less experimental data are available for delineating the role of ICP on the behaviors of LC. In this work, we present one dataset from LP patients and reconstruct its two-dimensional computational model of the ONH based on the patient’s images to delineate the role of ICP on ONH mechanics. The changes of LC depth, BMO width and papillary height were compared between the simulation and clinical dataset. The maximum principal strain of LC was calculated to reinforce its link with mechanosensitive cells in ONH.

Interactions Between Factors Influencing Optic Nerve Head Biomechanics

2007 ◽  
Author(s):  
Ian A. Sigal ◽  
John G. Flanagan ◽  
C. Ross Ethier
Keyword(s):  
Optic Nerve ◽  
Optic Nerve Head ◽  
Mechanical Response ◽  
Ganglion Cells ◽  
Cell Damage ◽  
Mechanical Strain ◽  
Lamina Cribrosa ◽  
Retinal Ganglion ◽  
The Finite Element Method ◽  
Primary Risk Factor

Glaucoma is the second most common cause of blindness worldwide, and elevated intraocular pressure (IOP) is the primary risk factor for developing this disease. It has been postulated that IOP-induced mechanical strain on optic nerve head (ONH) glial cells leads to retinal ganglion cell damage and the consequent loss of vision in glaucoma. To better evaluate this theory it is important to understand the biomechanical environment within the ONH. Unfortunately it is very difficult to make measurements in the ONH, and it is particularly difficult to access the region in the ONH where the ganglion cells are thought to be injured, namely the lamina cribrosa. We have therefore developed models of the ONH and used the finite element method (FEM) to predict ONH mechanical response to changes in IOP [1].

Anterior Lamina Cribrosa Surface Position in Idiopathic Intracranial Hypertension and Glaucoma

2016 ◽  
Vol 27 (1) ◽  
pp. 55-61 ◽  
Author(s):  
Jenni M. Villarruel ◽  
Xiao Q. Li ◽  
Daniella Bach-Holm ◽  
Steffen Hamann
Keyword(s):  
Optic Nerve ◽  
Intracranial Hypertension ◽  
Optic Nerve Head ◽  
Idiopathic Intracranial Hypertension ◽  
Open Angle Glaucoma ◽  
Fluid Pressure ◽  
Lamina Cribrosa ◽  
Enhanced Depth Imaging ◽  
Mean Deviation ◽  
Control Subjects

Purpose To compare the anterior lamina cribrosa (LC) surface position in patients with idiopathic intracranial hypertension (IIH), primary open-angle glaucoma (high-tension glaucoma [HTG] and normal-tension glaucoma [NTG]), and healthy controls using enhanced depth imaging spectral-domain optical coherence tomography (EDI-OCT). Methods This was a retrospective, cross-sectional observational study of 11 eyes with IIH, 20 eyes with HTG, 20 eyes with NTG, and 37 control eyes. Serial horizontal B-scans of the optic nerve head were obtained using EDI-OCT. The LC depth, defined as the distance from the Bruch membrane opening plane to the anterior LC surface, was manually measured on selected B-scans covering the central three-quarters of the optic nerve head in each eye. Results Mean LC depth in patients with IIH (325.2 ± 92.1 µm) was significantly (p<0.01) decreased compared to control subjects (387.8 ± 53.9 µm). In HTG, the mean LC depth (493.0 ± 115.2 µm) was significantly increased compared to NTG (376.6 ± 27.1 µm, p<0.05) and control subjects (332.7 ± 53.1 µm, p<0.001). The trans-LC pressure difference (TLPD) (intraocular pressure − cerebrospinal fluid pressure) was positively correlated with the LC depth (r = 0.96, p<0.001) and inversely correlated with visual field perimetric mean deviation in patients with IIH (r = -0.88, p<0.001). Conclusions The LC is positioned anteriorly in patients with IIH and posteriorly in glaucomatous eyes compared to normal controls. The positional changes of the LC could be a result of the TLPD between the intraocular and intracranial pressure compartments.

The role of lamina cribrosa cells in optic nerve head fibrosis in glaucoma

2016 ◽  
Vol 142 ◽  
pp. 102-109 ◽  
Author(s):  
Deborah M. Wallace ◽  
Colm J. O'Brien
Keyword(s):  
Optic Nerve ◽  
Optic Nerve Head ◽  
Lamina Cribrosa

scholarly journals Choroidal microvasculature dropout is spatially associated with optic nerve head microvasculature loss in open-angle glaucoma

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Min Kyung Song ◽  
Joong Won Shin ◽  
Jin Yeong Lee ◽  
Ji Wook Hong ◽  
Michael S. Kook
Keyword(s):  
Optic Nerve ◽  
Optic Nerve Head ◽  
Optical Coherence Tomography Angiography ◽  
Open Angle Glaucoma ◽  
Spatial Relationship ◽  
Vascular Supply ◽  
Open Angle ◽  
Regression Analyses ◽  
Angular Extent ◽  
Choroidal Vessels

AbstractThe presence of parapapillary choroidal microvasculature dropout (CMvD) may affect optic nerve head (ONH) perfusion in glaucoma patients, since parapapillary choroidal vessels provide vascular supply to the neighboring ONH. However, it remains to be determined whether the presence of parapapillary CMvD is associated with diminished perfusion in the nearby ONH. The present study investigated the spatial relationship between CMvD and ONH vessel density (ONH-VD) loss in open-angle glaucoma (OAG) eyes using optical coherence tomography angiography (OCT-A). This study included 48 OAG eyes with a single localized CMvD confined to the inferotemporal parapapillary sector and 48 OAG eyes without CMvD, matched for demographic and ocular characteristics. Global and regional ONH-VD values were compared between eyes with and without CMvD. The relationships between ONH-VD outcomes and clinical variables were assessed. ONH-VDs at the inferotemporal ONH sectors corresponding to the CMvD location were significantly lower in eyes with compared to those without CMvD. Multivariable linear regression analyses indicated that a lower inferotemporal ONH-VD was independently associated with CMvD presence and a greater CMvD angular extent (both P < 0.05). The localized presence of parapapillary CMvD in OAG eyes is significantly associated with ONH-VD loss in the neighboring ONH location, with a spatial correlation.

scholarly journals The role of nitric oxide and endothelin on optic nerve head blood flow autoregulation

2012 ◽  
Vol 13 (Suppl 1) ◽  
pp. A28
Author(s):  
Doreen Schmidl ◽  
Agnes Boltz ◽  
Semira Kaya ◽  
René Werkmeister ◽  
Reinhard Told ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Optic Nerve ◽  
Optic Nerve Head

scholarly journals Bruch’s membrane opening enlargement and its implication on the myopic optic nerve head

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Mi Sun Sung ◽  
Min Young Heo ◽  
Hwan Heo ◽  
Sang Woo Park
Keyword(s):  
Optic Nerve ◽  
Optic Nerve Head ◽  
Lamina Cribrosa ◽  
Cross Sectional Study ◽  
Multivariate Regression Model ◽  
Bruch's Membrane ◽  
Bruch’S Membrane ◽  
Cross Sectional ◽  
Bruch’S Membrane Opening ◽  
Parapapillary Atrophy

AbstractWe examined the association between Bruch’s membrane opening (BMO) area and various ocular parameters and investigated the implication of BMO enlargement on the myopic optic nerve head. One hundred eighty-five myopic eyes were included in this cross-sectional study. Among the included eyes, 53 having axial lengths between 26 and 27 mm were further analyzed to investigate the association between BMO area and various ocular parameters. BMO area, BMO-minimum rim width (BMO-MRW), peripapillary choroidal thickness (pCT), width of β-parapapillary atrophy with and without Bruch’s membrane (PPA+BM and PPA−BM), and presence of lamina cribrosa (LC) defect were evaluated. We found that BMO area tended to increase with increasing axial length, but varied among the highly myopic eyes even though they had similar degrees of myopia. In the subgroup analysis of eyes with axial lengths between 26 and 27 mm, BMO area was highly variable and it significantly correlated with PPA−BM width and temporal-inferior, nasal-inferior, and nasal BMO-MRW and pCT. LC defects were more common in myopic eyes with enlarged BMO. A multivariate regression model revealed that higher intraocular pressure, enlarged BMO, and thinner BMO-MRW were associated with LC defects in highly myopic eyes. These findings should be considered when evaluating myopic eyes.

scholarly journals Longitudinal assessment of optic nerve head changes using optical coherence tomography in a primate microbead model of ocular hypertension

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Anita S. Y. Chan ◽  
Tin Aung Tun ◽  
John C. Allen ◽  
Myoe Naing Lynn ◽  
Sai Bo Bo Tun ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Optic Nerve ◽  
Ocular Hypertension ◽  
Optic Nerve Head ◽  
Structural Damage ◽  
Structural Changes ◽  
Lamina Cribrosa ◽  
Optical Coherence ◽  
Longitudinal Assessment ◽  
The Mean

Abstract In humans, the longitudinal characterisation of early optic nerve head (ONH) damage in ocular hypertension (OHT) is difficult as patients with glaucoma usually have structural ONH damage at the time of diagnosis. Previous studies assessed glaucomatous ONH cupping by measuring the anterior lamina cribrosa depth (LCD) and minimal rim width (MRW) using optical coherence tomography (OCT). In this study, we induced OHT by repeated intracameral microbead injections in 16 cynomolgus primates (10 unilateral; 6 bilateral) and assessed the structural changes of the ONH longitudinally to observe early changes. Elevated intraocular pressure (IOP) in OHT eyes was maintained for 7 months and serial OCT measurements were performed during this period. The mean IOP was significantly elevated in OHT eyes when compared to baseline and compared to the control eyes. Thinner MRW and deeper LCD values from baseline were observed in OHT eyes with the greatest changes seen between month 1 and month 2 of OHT. Both the mean and maximum IOP values were significant predictors of MRW and LCD changes, although the maximum IOP was a slightly better predictor. We believe that this model could be useful to study IOP-induced early ONH structural damage which is important for understanding glaucoma pathogenesis.

Sign in / Sign up

Export Citation Format

Share Document