Intracranial Pressure Influences the Behavior of the Optic Nerve Head

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Yi Hua ◽  
Junfei Tong ◽  
Deepta Ghate ◽  
Sachin Kedar ◽  
Linxia Gu
Keyword(s):  
Optic Nerve ◽  
Intracranial Pressure ◽  
Optic Nerve Head ◽  
Neural Tissue ◽  
Lamina Cribrosa ◽  
Patient Specific ◽  
Orthogonal Experimental Design ◽  
Ischemic Optic Neuropathy ◽  
Pia Mater ◽  
Minimal Impact

In this work, the biomechanical responses of the optic nerve head (ONH) to acute elevations in intracranial pressure (ICP) were systematically investigated through numerical modeling. An orthogonal experimental design was developed to quantify the influence of ten input factors that govern the anatomy and material properties of the ONH on the peak maximum principal strain (MPS) in the lamina cribrosa (LC) and postlaminar neural tissue (PLNT). Results showed that the sensitivity of ONH responses to various input factors was region-specific. In the LC, the peak MPS was most strongly dependent on the sclera thickness, LC modulus, and scleral canal size, whereas in the PLNT, the peak MPS was more sensitive to the scleral canal size, neural tissue modulus, and pia mater modulus. The enforcement of clinically relevant ICP in the retro-orbital subarachnoid space influenced the sensitivity analysis. It also induced much larger strains in the PLNT than in the LC. Moreover, acute elevation of ICP leads to dramatic strain distribution changes in the PLNT, but had minimal impact on the LC. This work could help to better understand patient-specific responses, to provide guidance on biomechanical factors resulting in optic nerve diseases, such as glaucoma, papilledema, and ischemic optic neuropathy, and to illuminate the possibilities for exploiting their potential to treat and prevent ONH diseases.

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.

OCT based interpretation of the optic nerve head anatomy in young adults with retinal vascular occlusions and ischemic optic neuropathy

2020 ◽  
pp. 112067212095759
Author(s):  
Amy Dai ◽  
Lasse Malmqvist ◽  
Simon P Rothenbuehler ◽  
Steffen Hamann
Keyword(s):  
Young Adults ◽  
Optic Nerve ◽  
Optic Nerve Head ◽  
Vascular Occlusion ◽  
Retinal Artery Occlusion ◽  
Artery Occlusion ◽  
Ischemic Optic Neuropathy ◽  
Vein Occlusion ◽  
Retinal Vascular Occlusion ◽  
Retinal Artery

Purpose: To examine optic nerve head (ONH) anatomy in young adults with central retinal vein occlusion (CRVO), branch retinal vein occlusion (BRVO), central retinal artery occlusion (CRAO), branch retinal artery occlusion (BRAO) or nonarteritic anterior ischemic optic neuropathy (NA-AION) in order to look for associated, potentially predisposing anomalies. Methods: Cross-sectional study including 54 patients (ages 16–50 years) diagnosed from 2009 to 2018 with CRVO, BRVO, CRAO, BRAO, or NA-AION. Using Optical Coherence Tomography the presence of optic disc drusen (ODD), prelaminar hyperreflective lines and peripapillary hyperreflective ovoid mass-like structures (PHOMS), and determination of scleral canal size, retinal nerve fiber layer thickness (RNFLT) and macular ganglion cell layer thickness (GCLT) was obtained. Data for retinal vascular occlusion patients were grouped and analyzed together. Results: ODD were found in 13% of all patients, 2% of retinal vascular occlusion patients and 67% of NA-AION patients ( p < 0.0001). Prelaminar hyperreflective lines were found in 35% of all patients, 24% of retinal vascular occlusion patients and 89% of NA-AION patients ( p = 0.0005). PHOMS were found in 20% of all patients, 13% of retinal vascular occlusion patients and 56% of NA-AION patients ( p = 0.012). RNFLT was decreased in ODD patients compared to patients without ODD ( p = 0.01). Scleral canal diameter and GCLT was not correlated with ODD, prelaminar hyperreflective lines or PHOMS. Conclusion: ODD, prelaminar hyperreflective lines and PHOMS were more frequent in NA-AION patients compared to retinal vascular occlusion patients. The prevalence of ODD in retinal vascular occlusion patients was similar to the reported prevalence in the general population.

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