• Journal of Biomedical Engineering Research
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• v.24 no.2
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• pp.91-97
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• 2003

The Propose of this paper is hierarchical detection method for the optic disc in fundus image. We detected the optic disc boundary by using the Prior information. It is based on the anatomical knowledge of fundus which are the vessel information. the image complexity. and etc. The whole method can be divided into three stages . First, we selected the region of interest(ROI) which included optic disc region. This is used to calculate location and size of the optic disc which are prior knowledge to simplify image preprocessing. And then. we divided the fundus image into numberous regions with watershed algorithm and detected intial boundary of the optic disc by reducing the number of the separated regions in ROI. Finally, we have searching the defective parts of boundary as a result of serious vessel interference in order to detect the accurate boundary of optic disc and we have removing and interpolating them.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.312-316
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• 2004

The paper presents a technique to identify the boundary of the optic disc in infant retinal digital images using an approach based on active contours (snakes). The technique can be used to be develop a automate system in order to help the ophthalmologist's diagnosis the retinopathy of prematurity (ROP) disease which may occurred on preterm infant,. The optic disc detection is one of the fundamental step which could help to create an automate diagnose system for the doctors we use a new kind of active contour (snake) method has been developed by Chenyang et. al. [1], based on a new type of external force field, called gradient vector flow, or GVF. GVF is computed as a diffusion of the gradient vectors of a gray-level or binary edge map derived from the image. The testing results on a set of infant retinal ROP images verify the effectiveness of the proposed methods. We show that GVF has a large capture range and it's able to move snakes into boundary concavities of optic disc and finally the optic disk boundary was determined.

• Korean Journal of Veterinary Research
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• v.36 no.4
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• pp.915-918
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• 1996

This study was performed to investigate the normal ocular fundus in 30 Korean native goats. The shape of two peaks of a mountain was shown in the tapetal fundus which was mostly greenish-blue color. The nontapetal fundus which was differentiated from the tapetal fundus, was generally a uniform shade with dark blue. The optic disc was nearly round and varied in color : orange, gray, tan and various combinations. It was mostly located at the junctional area of the nontapetal and the tapetal fundus. In the retinal vasculature, three or four major arterioles and two or three major venules emerged from the optic disc and the arterioles could be distinguished from the venules. The superior arteriole and venule in the tapetal fundus did not twist each other.

• Journal of Veterinary Science
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• v.22 no.5
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• pp.65.1-65.12
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• 2021

Background: To assess the normal retina of the pigeon eye using spectral domain optical coherence tomography (SD-OCT) and establish a normative reference. Methods: Twelve eyes of six ophthalmologically normal pigeons (Columba livia) were included. SD-OCT images were taken with dilated pupils under sedation. Four meridians, including the fovea, optic disc, red field, and yellow field, were obtained in each eye. The layers, including full thickness (FT), ganglion cell complex (GCC), thickness from the retinal pigmented epithelium to the outer nuclear layer (RPE-ONL), and from the retinal pigmented epithelium to the inner nuclear layer (RPE-INL), were manually measured. Results: The average FT values were significantly different among the four meridians (p < 0.05), with the optic disc meridian being the thickest (294.0 ± 13.9 ㎛). The average GCC was thickest in the optic disc (105.3 ± 27.1 ㎛) and thinnest in the fovea meridian (42.8 ± 15.3 ㎛). The average RPE-INL of the fovea meridian (165.5 ± 18.3 ㎛) was significantly thicker than that of the other meridians (p < 0.05). The average RPE-ONL of the fovea, optic disc, yellow field, and red field were 91.2 ± 5.2 ㎛, 87.7 ± 5.3 ㎛, 87.6 ± 6.5 ㎛, and 91.4 ± 3.9 ㎛, respectively. RPE-INL and RPE-ONL thickness of the red field meridian did not change significantly with measurement location (p > 0.05). Conclusions: Measured data could be used as normative references for diagnosing pigeon retinopathies and further research on avian fundus structure.

• Tuberculosis and Respiratory Diseases
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• v.43 no.2
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• pp.236-242
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• 1996

Intracranial tuberculoma results from hematogenous spread of pulmonary, intestinal or urogenital tuberculosis. However, it might be caused by pulmonary tuberculosis, mainly. Clinically, symptoms of intracranial tuberculoma are headache and seizure, its symptoms are simillar to intracranial tumor. A 25-year-old-unmarried shopgirl was visited to this hospital because of headache, dizziness and visual disturbance for couple weeks in Sep. 1995. She had been treated with anti-tuberculosis agents of miliary tuberculosis during past nine months period. Brain MRI revealed intracranial tuberculoma and brain edema but not involved optic nerve. Ophthalmic examination revealed severe papilledema and splinter hemorrhage with bitemporal hemianopsis and central scotoma. This finding was strongly suggested of optic disc tuberculoma. Her symptoms became much better following repeated retrobulbar steroid injection with continuous anti-tuberculosis agents. We report a interesting case with intracranial tuberculoma and optic disc tuberculoma associated by miliary tuberculosis during anti-tuberculous treatment.

• Journal of The Korean Ophthalmological Society
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• v.59 no.11
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• pp.1091-1096
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• 2018

Purpose: We report a case of bilateral nonarteritic anterior ischemic optic neuropathy (NAION) following acute angle-closure crisis (AACC). Case summary: A 76-year-old female visited our clinic because of a 1-day history of ocular pain and vision loss in both eyes. The visual acuity was 0.02 in both eyes and her intraocular pressure (IOP) was 52 mmHg in the right eye (RE) and 50 mmHg in the left eye (LE). She had corneal edema and a shallow anterior chamber in both eyes, with 4 mm fixed dilated pupils. After decreasing the IOP with intravenous mannitol, laser iridotomy was performed. However, 2 days later, visual acuity was further reduced to finger counting at 10 cm RE and at 50 cm LE, and her optic disc was swollen. Bilateral NAION following AACC was diagnosed. One month later, visual acuity slightly improved to 0.02 RE and 0.04 LE, and the optic disc edema resolved. A small cup-disc ratio, optic disc pallor, and atrophy were observed. Humphrey visual fields demonstrated superior and inferior altitudial visual field defects in the LE, and almost total scotoma in the RE. Conclusions: AACC can be a predisposing factor for NAION, so the relative afferent pupillary defect, papilledema, and presentation of other risk factors are important clues to a diagnosis of NAION.

• Korean Journal of Veterinary Research
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• v.29 no.1
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• pp.1-6
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• 1989

The number and distribution of the retinal ganglion cells in the 2 years old Korean native cattle was determined from whole fiat mounted preparation stained with methylene blue and thionin. The results were summarized as follows. 1. The total number of retinal ganglion cells was estimated to be 3,085,200 in the bovine retina ranging from $2,214mm^2$ in total area. 2. Visual streak was recognized at the area 2.5mm superior to the optic disc and ganglion cell density drops off rapidly to the directions superior to and inferior to the visual streak. 3. Area centralis ($6,800cells/mm^2$) was located at the area 10mm temporally from the point of 3mm superior to the optic disc. 4. The number of ${\alpha}-type$ ganglion cells (above $15{\mu}$) was 57,000 in the bovine retina and ${\alpha}-type$ ganglion cells constituted 18.5% of the total cells. 5. The relative frequency of ${\alpha}-type$ ganglion cells was higher in the peripheral regions than in the visual streak, especially higher in the superior-temporal quadrant than in other region of the bovine retina.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.146-149
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• 1997

Computerized densitometry was developed or the quantitative measurement of diffuse retinal nerve fiber layer (RNFL) atrophy and intra- and inter-operator reliability and clinical validity of this system were evaluated. Vertical diameter, center of the optic disc, and peripapillary circles which had radii of 1.5 and 2.5 times that of the optic disc were user-interactively determined in digitized RNFL photograph and density profile along each circle was measured and normalized. The areas under the normalized density profiles of the superior and the inferior segments in both circle were used or the study of RNFL. To determine the variability and correspondence in the measurements of density variations, 21 RNFL photographs of glaucoma patients which showed varying degrees of atrophy underwent computerized densitometry by two operators on two separate occasions. Coefficient of variation in the densitometric measurements was $1.2{\sim}5.4%$. Intra- and inter-operator reliabilities were excellent. The correlations between the densitometric values and mean deviations of Humphrey C30-2 visual field showed statistical significance. Computerized densitometry of RNFL photographs was useful in the objective and quantitative assessment of diffuse RNFL atrophy.

• Childhood Kidney Diseases
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• v.25 no.2
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• pp.128-132
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• 2021

Morning glory syndrome (MGS) is a rare congenital optic disc anomaly with a characteristic fundal finding with severe visual impairment. It may occur in association with various systemic manifestations, even though most of the reported cases were isolated. A 6-year-old male visited the nephrology clinic with a history of microscopic hematuria and at the age of 12 years, he was diagnosed thin glomerular basement membrane nephropathy by kidney biopsy. After the following years, the patient had progressive deterioration of visual acuity, and diagnosed as MGS. Whole Exome Sequencing of this patient and his mother revealed heterozygous COL4A4 mutations [c.81_86del (p.Ile29_Leu30del)]. It is more reasonable to consider MGS seen in this patient as a coincidental finding of autosomal dominant Alport syndrome. To our knowledge, this case represents the first case report of autosomal dominant Alport syndrome associated with MGS.

• Journal of Cerebrovascular and Endovascular Neurosurgery
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• v.20 no.4
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• pp.241-247
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• 2018

Treatment of paraclinoid aneurysms weather by surgery, or endovascular embolization has a risk of visual loss due to optic neuropathy, or diplopia due to cranial nerve palsies. Visual complications occur immediately after the clipping, whereas they can occur variable time after endovascular coiling. Recently, endovascular coiling for paraclinoid aneurysm is regarded as a safe and feasible treatment. But it still has risks of acute thromboembolic complication, or cranial nerve palsies. A 45-year-old woman was referred from local hospital to our hospital due to ruptured large ICA dorsal wall aneurysm. A total of 12 coils (195 cm) were used for obliteration of aneurysm. Postoperative diffusion weighted image showed no abnormal signal intensity lesion and magnetic resonance angiography demonstrated no sign of vasospasm, or vessel narrowing. But, she complained visual problem 23 days after coil embolization. Ophthalmologist confirmed the left optic disc atrophy on fundoscopy. Although steroid was started, but monocular blindness did not recover completely. The endovascular embolization of paraclinoid aneurysm, especially projecting superiorly with large irregular shape, has the risk of progressive visual loss because of the proximity to optic nerve.