• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.12
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• pp.3919-3924
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• 2009

To evaluate clinical results of silicone oil injection for retinal detachment. The 45 eyes of 44 patients underwent vitrectomy and silicone oil injection from 1999 to 2002. 1.There were no history of previous retinal surgery and ocular trauma. In 24 of the 45 eyes(53%) visual acuity increased and stabilized in 18 of the 45 eyes(40%). 2. 1 of 16 eyes(6.3%) had recurred retinal detachment after silicone oil removal. 3. Final retinal reattachment was achieved in 44 eyes(97%). Postoperative complications were cataract(16 eyes), glaucoma(10 eyes), emulsification of silicone oil(5 eyes), keratopathy(2 eyes) and recurrent retinal detachment(1 eye). These results show that silicone oil injection for primary retinal detachment yields a high rate of anatomic success and the good visual outcome

• Molecules and Cells
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• v.23 no.2
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• pp.215-219
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• 2007

In mammals light input resets the central clock of the suprachiasmatic nucleus by inducing secretion of pituitary adenylate cyclase-activating polypeptide (PACAP) from retinal ganglion cells (RGCs). We previously showed that thyroid transcription factor 1 (TTF-1), a homeodomain-containing transcription factor, specifically regulates PACAP gene expression in the rat hypothalamus. In the present study we examined the expression of TTF-1 in PACAP-synthesizing retinal cells. Fluorescence in situ hybridization (FISH) showed that it is abundantly expressed in RGCs of the superior region of the retina, but in only a small subset of RGCs in the inferior region. Double FISH experiments revealed that TTF-1 is exclusively expressed in PACAP-producing RGCs. These results suggest that TTF-1 plays a regulatory role in PACAP-expressing retinal ganglion cells.

• International Journal of Computer Science & Network Security
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• v.23 no.3
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• pp.187-192
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• 2023

With development of information technology and necessity for high security, using different identification methods has become very important. Each biometric feature has its own advantages and disadvantages and choosing each of them depends on our usage. Retinal scanning is a bio scale method for identification. The retina is composed of vessels and optical disk. The vessels distribution pattern is one the remarkable retinal identification methods. In this paper, a new approach is presented for identification via retinal images using LBP and hog methods. In the proposed method, it will be tried to separate the retinal vessels accurately via machine vision techniques which will have good sustainability in rotation and size change. HOG-based or LBP-based methods or their combination can be used for separation and also HSV color space can be used too. Having extracted the features, the similarity criteria can be used for identification. The implementation of proposed method and its comparison with one of the newly-presented methods in this area shows better performance of the proposed method.

• Current Optics and Photonics
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• v.8 no.2
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• pp.183-191
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• 2024

High-resolution retinal imaging based on adaptive optics (AO) is important for early diagnosis related to retinal diseases. However, in practical applications, closed-loop AO correction takes a relatively long time, and traditional open-loop correction methods have low accuracy in correction, leading to unsatisfactory imaging results. In this paper, a SH-U-net-based open-loop AO wavefront correction method is presented for a retinal AO imaging system. The SH-U-net builds a mathematical model of the entire AO system through data training, and the Root mean square (RMS) of the distorted wavefront is 0.08λ after correction in the simulation. Furthermore, it has been validated in experiments. The method improves the accuracy of wavefront correction and shortens the correction time.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.321-325
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• 2004

Retinopathy of Prematurity (ROP) is a common retinal neovascular disorder of premature infants. It can be characterized by inappropriate and disorganized vessel. This paper present a method for blood vessel detection on infant retinal images. The algorithm is designed to detect the retinal vessels. The proposed method applies a Lapalacian of Gaussian as a step-edge detector based on the second-order directional derivative to identify locations of the edge of vessels with zero crossings. The procedure allows parameters computation in a fixed number of operations independent of kernel size. This method is composed of four steps : grayscale conversion, edge detection based on LOG, noise removal by adaptive Wiener filter & median filter, and Otsu's global thresholding. The algorithm has been tested on twenty infant retinal images. In cooperation with the Digital Imaging Research Centre, Kingston University, London and Department of Opthalmology, Imperial College London who supplied all the images used in this project. The algorithm has done well to detect small thin vessels, which are of interest in clinical practice.

• The Korean Journal of Physiology and Pharmacology
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• v.13 no.3
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• pp.221-227
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• 2009

For successful restoration of visual function by a visual neural prosthesis such as retinal implant, electrical stimulation should evoke neural responses so that the informat.ion on visual input is properly represented. A stimulation strategy, which means a method for generating stimulation waveforms based on visual input, should be developed for this purpose. We proposed to use the decoding of visual input from retinal ganglion cell (RGC) responses for the evaluation of stimulus encoding strategy. This is based on the assumption that reliable encoding of visual information in RGC responses is required to enable successful visual perception. The main purpose of this study was to determine the influence of inter-dependence among stimulated RGCs activities on decoding accuracy. Light intensity variations were decoded from multiunit RGC spike trains using an optimal linear filter. More accurate decoding was possible when different types of RGCs were used together as input. Decoding accuracy was enhanced with independently firing RGCs compared to synchronously firing RGCs. This implies that stimulation of independently-firing RGCs and RGCs of different types may be beneficial for visual function restoration by retinal prosthesis.

• Design & Manufacturing
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• v.17 no.1
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• pp.40-47
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• 2023

Macular degeneration and glaucoma are representative age-related retinal diseases that rank second and third in the prevalence of retinal diseases, and are a kind of degenerative neurological disease. Irreversible visual acuity and visual field damage may occur, and the number of patients is rapidly increasing as the population ages. Since this retinal disease is a chronic disease, continuous drug treatment is required. There are various drug delivery methods for treatment, but direct injection of the drug into the intravitreal is the most effective for continuous delivery of the drug over a long period of time. In order to solidify Dexamethasone, a retinal disease treatment, and insert it into the primary intravitreal, it is important to develop a technology to miniaturize the treatment and an applicator to deliver the treatment. In this study, a mold technology was developed to integrate the cannula and hub, which are one part of applicator. In addition, surface treatment was performed on the outside of the cannula to improve the bonding strength between the cannula and the hub, and the bonding strength according to each condition was analyzed through a tensile test.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.614-616
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• 2021

The world faces difficulties in terms of eye care, including treatment, quality of prevention, vision rehabilitation services, and scarcity of trained eye care experts. However, it is difficult to develop a method for classifying various ocular diseases because the existing dataset for retinal image disclosure does not consist of various diseases found in clinical practice. We propose a method for classifying ocular diseases using the Retinal Fundus Multi-disease Image Dataset (RFMiD), a dataset published in the ISBI-2021 challenge. Our goal is to develop a robust and generalizable model for screening retinal images into normal and abnormal categories. The performance of the proposed model shows a value of 0.9782 for the test dataset as an area under the curve (AUC) score.

• International Journal of Industrial Entomology and Biomaterials
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• v.47 no.2
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• pp.90-98
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• 2023

The human eye, constantly exposed to solar radiation, can be damaged by UV radiation. In particular, ultraviolet B (UVB)-induced damage plays an important role in retinal degeneration and cell aging. In this study, we investigated the protective effects of the methanol extract of Oxya chinensis sinuosa (OCM), an edible insect known for its high protein content (64.2%), and various pharmacological effects, on human retinal pigment epithelial cells. ARPE-19 cells were treated with OCM and subsequently UVB irradiated. Our results showed that OCM effectively attenuates UVB-induced cell damage by reducing MAPK phosphorylation (JNK and p38 MAPK). Additionally, OCM increased the phosphorylation of Akt, and cell cycle regulators, including p21 and p27, in a dose-dependent manner. Moreover, OCM treatment increased ARPE-19 cell proliferation by activating the S6K1/S6 pathway. This study suggests that OCM prevents UVB-induced retinal cell damage by increasing cell proliferation via ROS reduction, suggesting its potential as a functional therapeutic superfood against retinal cell damage.

• The Korean Journal of Physiology and Pharmacology
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• v.19 no.2
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• pp.167-175
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• 2015

A retinal prosthesis is being developed for the restoration of vision in patients with retinitis pigmentosa (RP) and age-related macular degeneration (AMD). Determining optimal electrical stimulation parameters for the prosthesis is one of the most important elements for the development of a viable retinal prosthesis. Here, we investigated the effects of different charge-balanced biphasic pulses with regard to their effectiveness in evoking retinal ganglion cell (RGC) responses. Retinal degeneration (rd1) mice were used (n=17). From the ex-vivo retinal preparation, retinal patches were placed ganglion cell layer down onto an $8{\times}8$ multielectrode array (MEA) and RGC responses were recorded while applying electrical stimuli. For asymmetric pulses, 1st phase of the pulse is the same with symmetric pulse but the amplitude of 2nd phase of the pulse is less than $10{\mu}A$ and charge balanced condition is satisfied by lengthening the duration of the pulse. For intensities (or duration) modulation, duration (or amplitude) of the pulse was fixed to $500{\mu}s$($30{\mu}A$), changing the intensities (or duration) from 2 to $60{\mu}A$(60 to $1000{\mu}s$). RGCs were classified as response-positive when PSTH showed multiple (3~4) peaks within 400 ms post stimulus and the number of spikes was at least 30% more than that for the immediate pre-stimulus 400 ms period. RGC responses were well modulated both with anodic and cathodic phase-1st biphasic pulses. Cathodic phase-1st pulses produced significantly better modulation of RGC activity than anodic phase-1st pulses regardless of symmetry of the pulse.