Laser Speckle and Hydrogen Gas Clearance Measurements of Optic Nerve Circulation in Albino and Pigmented Rabbits With or Without Optic Disc Atrophy

2014 ◽  
Vol 55 (12) ◽  
pp. 7991-7996 ◽  
Author(s):  
N. Aizawa ◽  
F. Nitta ◽  
H. Kunikata ◽  
T. Sugiyama ◽  
T. Ikeda ◽  
...  
Keyword(s):  
Optic Nerve ◽  
Optic Disc ◽  
Hydrogen Gas ◽  
Laser Speckle ◽  
Hydrogen Gas Clearance ◽  
Pigmented Rabbits

Comparison of CCD-equipped laser speckle flowgraphy with hydrogen gas clearance method in the measurement of optic nerve head microcirculation in rabbits

2013 ◽  
Vol 108 ◽  
pp. 10-15 ◽  
Author(s):  
Hiroaki Takahashi ◽  
Tetsuya Sugiyama ◽  
Hideki Tokushige ◽  
Takatoshi Maeno ◽  
Toru Nakazawa ◽  
...  
Keyword(s):  
Optic Nerve ◽  
Optic Nerve Head ◽  
Hydrogen Gas ◽  
Laser Speckle ◽  
Laser Speckle Flowgraphy ◽  
Hydrogen Gas Clearance

scholarly journals Effect of lomerizine on the microcirculation in the optic nerve head in rabbits using a hydrogen gas clearance technique.

1999 ◽  
Vol 79 ◽  
pp. 191
Author(s):  
Nobuko Toriu ◽  
Masamitsu Shimazawa ◽  
Masaaki Sasaoka ◽  
Tetsuya Sugiyama ◽  
Hideaki Hara
Keyword(s):  
Optic Nerve ◽  
Optic Nerve Head ◽  
Hydrogen Gas ◽  
Hydrogen Gas Clearance ◽  
Clearance Technique

scholarly journals Two-Stage Mask-RCNN Approach for Detecting and Segmenting the Optic Nerve Head, Optic Disc, and Optic Cup in Fundus Images

2020 ◽  
Vol 10 (11) ◽  
pp. 3833 ◽  
Author(s):  
Haidar Almubarak ◽  
Yakoub Bazi ◽  
Naif Alajlan
Keyword(s):  
Optic Nerve ◽  
Optic Disc ◽  
Optic Nerve Head ◽  
Fine Tuning ◽  
Fundus Images ◽  
Two Stage ◽  
Second Stage ◽  
Retinal Fundus Images ◽  
Tuning Strategy ◽  
Retinal Fundus

In this paper, we propose a method for localizing the optic nerve head and segmenting the optic disc/cup in retinal fundus images. The approach is based on a simple two-stage Mask-RCNN compared to sophisticated methods that represent the state-of-the-art in the literature. In the first stage, we detect and crop around the optic nerve head then feed the cropped image as input for the second stage. The second stage network is trained using a weighted loss to produce the final segmentation. To further improve the detection in the first stage, we propose a new fine-tuning strategy by combining the cropping output of the first stage with the original training image to train a new detection network using different scales for the region proposal network anchors. We evaluate the method on Retinal Fundus Images for Glaucoma Analysis (REFUGE), Magrabi, and MESSIDOR datasets. We used the REFUGE training subset to train the models in the proposed method. Our method achieved 0.0430 mean absolute error in the vertical cup-to-disc ratio (MAE vCDR) on the REFUGE test set compared to 0.0414 obtained using complex and multiple ensemble networks methods. The models trained with the proposed method transfer well to datasets outside REFUGE, achieving a MAE vCDR of 0.0785 and 0.077 on MESSIDOR and Magrabi datasets, respectively, without being retrained. In terms of detection accuracy, the proposed new fine-tuning strategy improved the detection rate from 96.7% to 98.04% on MESSIDOR and from 93.6% to 100% on Magrabi datasets compared to the reported detection rates in the literature.

Optic disc coloboma (the morning glory syndrome) and optic nerve coloboma associated with transsphenoidal meningoencephalocele

2003 ◽  
Vol 45 (2) ◽  
pp. 71-76 ◽  
Author(s):  
Mutlu Sağlam ◽  
Üzeyir Erdem ◽  
Murat Kocaoğlu ◽  
Cem Tayfun ◽  
Taner Üçöz ◽  
...  
Keyword(s):  
Optic Nerve ◽  
Optic Disc ◽  
Morning Glory ◽  
Morning Glory Syndrome ◽  
Optic Disc Coloboma ◽  
Optic Nerve Coloboma

Gastric mucosal hyperemia due to acid backdiffusion depends on splanchnic nerve activity

1992 ◽  
Vol 262 (3) ◽  
pp. G505-G509 ◽  
Author(s):  
P. Holzer ◽  
I. T. Lippe
Keyword(s):  
Nicotinic Acetylcholine Receptors ◽  
Mucosal Blood Flow ◽  
Gastric Mucosal Blood Flow ◽  
Hydrogen Gas ◽  
Mucosal Barrier ◽  
Neural Pathways ◽  
Hydrogen Gas Clearance ◽  
Celiac Ganglion ◽  
Arterial Blood ◽  
Splanchnic Nerves

Acid backdiffusion through a disrupted gastric mucosal barrier leads to an increase in gastric mucosal blood flow (MBF). This response involves afferent neurons that pass through the celiac ganglion. The present study examined the neural pathways that underlie the rise in MBF caused by gastric perfusion with 15% ethanol in 0.15 N HCl. MBF was measured by the hydrogen gas clearance technique in urethan-anesthetized rats. Mucosal hyperemia due to acid backdiffusion was not changed by acute bilateral subdiaphragmatic vagotomy but was blocked by acute removal of the celiac-superior mesenteric ganglion complex or acute bilateral transection of the greater splanchnic nerves. Hexamethonium (85 mumol/kg iv) also attenuated the rise in MBF due to acid backdiffusion, whereas guanethidine (0.225 mmol/kg sc) had no effect. None of the procedures and drug treatments altered basal MBF to a significant extent. Transection of the splanchnic nerves, hexamethonium, and guanethidine lowered mean arterial blood pressure, but hypotension as such did not significantly influence the hyperemic response under study. Taken together, the previous and present data indicate that the rise in MBF caused by acid backdiffusion depends on the integrity of afferent and efferent neural pathways that run in the splanchnic nerves and through the celiac ganglion. The efferent pathway involves ganglionic transmission through nicotinic acetylcholine receptors but is independent of noradrenergic neurons.

scholarly journals Retrobulbar diameter of optic nerve in glaucoma

2009 ◽  
Vol 137 (3-4) ◽  
pp. 130-133
Author(s):  
Ivan Stefanovic ◽  
Ivan Marjanovic ◽  
Gordana Vlajkovic
Keyword(s):  
Intraocular Pressure ◽  
Optic Nerve ◽  
Optic Disc ◽  
Complex Disease ◽  
Normal Values ◽  
Nerve Fibres ◽  
Ultrasound Diagnostics ◽  
Pearson Test ◽  
Two Parameters

Introduction. The ultrasound diagnostics of the optic nerve includes the analysis of the optic nerve disc (PNO) and measuring of its retrobulbar diameter. With B-scan, by Schraeder's method, it is possible to measure very precisely the optic nerve, the pial diameter, the normal values for the pial diameter being 2.8-4.1 mm. In glaucoma, the disease that is most frequently associated with higher intraocular pressure, there comes the destruction of nerve fibres, which can be visualized as the excavation of the optic nerve disc. Objective. In this paper, we were interested in finding whether in glaucoma, and in what phase of the disease, the optic nerve starts growing thinner. Aware of many forms of this very complex disease, we were interested in knowing if the visualization of excavation on the optic nerve disc is related to diminishing of the pial diameter of the retrobulbar nerve part. Methods. There were treated the patients who had already had the diagnosis of glaucoma and the visualized excavation of the optic disc of various dimensions. Echographically, there was measured the thickness of the retrobulbar part of the optic nerve and the finding compared in relation to the excavation of the optic disc. Results. In all eyes with glaucoma, a normal size of the retrobulbar part of the optic nerve was measured, ranging from 3.01 to 3.91 mm with the median of 3.36 mm. Also, by testing the correlation between the thickness of the optic nerve and the excavation of the PNO, by Pearson test, we found that there was no correlation between these two parameters (r=0.109; p>0.05). Conclusion. In the patients with glaucoma, the retrobulbar part of the optic nerve is not thinner (it has normal values), even not in the cases with a totally excavated optic disc. There is no connection between the size of the PNO excavation and the thickness of the retrobulbar part of the optic nerve.

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