• Progress in Medical Physics
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• v.16 no.4
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• pp.214-219
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• 2005

As part of Korean retinal prosthesis project, we have provided preliminary experimental results regarding voltage parameters for the stimulation of chemically degenerated rabbit retina. Since our APB-treated chemically degenerated retina is only ON-pathway blocked, now we switch our experiments to more appropriate retinal degeneration model, genetically degenerated retina model (RD mouse: rd/rd (C3H/HeJ)). Before studying with RD mouse, we started control experiments with normal SD rat to understand characteristics of retinal ganglion ceil activity with postnatal maturation in rodents. Ganglion cell activities were recorded with 8${\times}$8 multi-electrode array. Moving spontaneous bursts appeared until postnatal day of 15. During pre-eye opening period, no light evoked response appeared. After postnatal day of 2 weeks (post-eye opening period), ON-, OFF- and ON/OFF response appeared. The fractional distributions of ON, OFF, and ON/OFF ganglion cell is about $40\%,\;50\%$, and $5\%$. The percentage ($\%$) of light evoked response in each dorso-temporal, ventral, and dorso-nasal area of eye is about $50\%,\;37.5\%$ and $12.5\%$, respectively. We concluded that the optimal period for experiment in rodent is about postnatal day of 2${\~}$3 weeks.

• Applied Microscopy
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• v.39 no.2
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• pp.185-189
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• 2009

Studies about the structure of Drosophila melanogaster retinal cell using electron microscopy have been carried out in details since 1960s. However, these results can have limitations in functional research because of two-dimensional structure. In this study, the adult retina of Drosophila melanogaster was investigated by employing high pressure freezing method, serial sections, high voltage electron microscopy, and 3-dimensional reconstruction method. From there results, mitochondria, microtubules, and nuclei were reconstructed as 3-dimensional structure using IMOD program. The 3D structure of these organelles showed that mitochondira mainly located in distal region near lens, and microtubule mainly located in distal and basal region. The 3D reconstruction of these organelles can be used for a critical evaluation in the dynamic change of cellular organelles caused by functional abnormality like retinal degeneration.

• Journal of The Korean Ophthalmological Society
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• v.59 no.12
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• pp.1152-1159
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• 2018

Purpose: We prospectively investigated clinical changes and long-term outcomes after administration of the drugs recommended by the Age-Related Eye Disease Study-2 to patients with intermediate age-related macular degeneration (AMD). Methods: This prospective multicenter study enrolled 79 eyes of 55 patients taking lutein and zeaxanthin. The primary endpoint was contrast sensitivity; this was checked every 12 months for a total of 36 months after treatment commenced. The secondary endpoints were visual acuity, central macular thickness, and drusen volume; the latter two parameters were assessed using spectral domain optical coherence tomography. Results: The mean patient age was $72.46{\pm}7.16years$. Contrast sensitivity gradually improved at both three and six cycles per degree. The corrected visual acuity was $0.13{\pm}0.14logMAR$ and did not change significantly over the 36 months. Neither the central macular thickness nor drusen volume changed significantly. Conclusions: Contrast sensitivity markedly improved after treatment, improving vision and patient satisfaction. Visual acuity, central retinal thickness, and drusen volume did not deteriorate. Therefore, progression of AMD and visual function deterioration were halted.

• Journal of The Korean Ophthalmological Society
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• v.59 no.11
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• pp.1024-1029
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• 2018

Purpose: We examined aqueous humor levels of 25-hydroxyvitamin D (vitamin D) in patients with age-related macular degeneration to investigate possible relationships between aqueous humor vitamin D levels and clinical manifestations. Methods: Patients > 50 years of age, 52 eyes of 34 patients with age-related macular degeneration, and 23 eyes of 17 patients treated with cataract surgery without retinal disease, were examined for aqueous humor vitamin D levels and compared. The experimental group was divided into two groups according to the median value of aqueous humor vitamin D levels. We compared the clinical manifestations of macular degeneration in both groups and identified relationships between aqueous humor vitamin D levels and clinical features. Results: Vitamin D levels in the aqueous humor were significantly lower in the experimental group than in the control group (experimental, $10.03{\pm}10.1ng/mL$ vs. control group, $40.8{\pm}16.4ng/mL$; p < 0.001). Patients with high vitamin D levels in the macular degeneration group had a higher percentage of fibrovascular pigment epithelial detachments than those in the low grade group (high grade group, 65% vs. low grade group, 27%; p = 0.003). Multiple linear regression analysis showed a significant correlation between vitamin D levels and the total number of anti-vascular endothelial growth factor intravitreal injections within 6 months (standardize coefficient, ${\beta}=-0.336$). Conclusions: Patients with wet age-related macular degeneration had significantly lower vitamin D levels in the aqueous humor compared to control group subjects of similar ages. However, in patients with macular degeneration, low vitamin D levels were associated with a greater number of intravitreal injections, while higher levels of vitamin D may lead to more advanced forms of fibrovascular retinal pigment epithelium and related low vision. These relationships were not always constant, so further studies on the relationships between local vitamin D levels and ocular disorders are needed.

• Journal of Korean Ophthalmic Optics Society
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• v.21 no.1
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• pp.69-76
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• 2016

Purpose: The study was conducted to determine that photoreceptors of mouse having pigment in RPE(retinal pigment epithelium) can be damaged by blue-light and apoptosis of specific cells among photoreceptors are induced by blue-light, and to assist the investigation of AMD(Age-related macular degeneration) mechanisms and development of AMD drugs. Methods: C57Black mice were injured by irradiating $2800{\pm}10lux$ of 463 nm LED for 6 hours after 24 hours dark adaptation and eyes were enucleated 1, 3, 7 days. Damage of retina induced by blue-light was determined by western blotting GFAP(Glial fibrillary acidic protein) expression. In the light-injured retina, cell death of photoreceptors was determined by TUNEL(Terminal deoxynucleotidyl transferase dUTP nick end labeling) assay. ERK(Extracellular signal-regulated kinases), JNK, and SRC(sarcoma) expression were assessed by western blotting to determine regulated pathway. Blue light-injured retina were immunostained with antibodies against Opsin and Rhodopsin as markers of photoreceptors to compared the damage cone cells with rod cells. Results: After 1, 3 and 7 days from exposure to blue-light, thickness of retina was more decreased than control, and more decreased at nuclear layer than at outer plexiform layer and GFAP expression was increased day 1 after blue-light injured. While phosphorylated ERK and SRC protein expressions at day 1 were increased after blue-light injured, phosphorylated c-JUN was decreased. Fluorescence intensity analysis showed that markers of cone and rod cells were decreased after blue-light injured and Opsin was more decreased than Rhodopsin. Conclusions: The study suggests possibilities that the blue-light promotes retinal damage and causes apoptotic cell death via ERK and SRC pathway in mouse retina, and blue-light retinal damage is more induced cone cells apoptosis than rod cells directly.

• Journal of The Korean Ophthalmological Society
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• v.59 no.12
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• pp.1142-1151
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• 2018

Purpose: We assessed the visual and anatomical outcomes, and the safety profile of long-term intravitreal anti-vascular endothelial growth factor (VEGF) injections (aflibercept, ranibizumab, and bevacizumab) given to treat neovascular age-related macular degeneration (NAMD). Methods: We analyzed medical records collected over 7 years of treatment-naive NAMD patients who received outpatient clinic-based intravitreal anti-VEGF injections. All were treated employing either "treat-and-extend" or "as needed" protocols at the discretion of the retinal specialist. The number of injections, adverse events associated with injection, and measures of visual acuity (VA), central foveal thickness (CFT), and intraocular pressure (IOP) were recorded. Results: Overall, we assessed 196 eyes of 196 patients (average age $68.6{\pm}9.6years$; 77 females). Patients received an average of $17.3{\pm}13.5$ injections over $78.0{\pm}16.5months$ of clinical follow-up. The initial mean VA (logMAR) was $0.75{\pm}0.58$ and the CFT was $349.7{\pm}152.6{\mu}m$. Both parameters exhibited maximal improvements at the 6-month visit (p < 0.05). However, the clinical outcomes worsened over the 7-year clinical course; the best-corrected visual acuity (BCVA) was $0.91{\pm}0.78$ and the CFT was $284.5{\pm}105.8{\mu}m$ at 7 years. The BCVA at 7 years was significantly correlated with the initial BCVA. IOP-related events increased 11-fold and anterior chamber reactions increased 3-fold over the years, but no significant complications such as endophthalmitis were recorded. Conclusions: The use of intravitreal anti-VEGF agents was associated with initial visual improvements over 6 months but did not prevent the worsening of NAMD over 5 years. The BCVA at the initial visit was a strong predictor of the final BCVA. A more intensive injection schedule might improve long-term outcomes.

• Polymer(Korea)
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• v.38 no.1
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• pp.24-30
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• 2014

Retinal pigment epithelium (RPE) plays an important role in maintaining the visual function and the degeneration of the RPE causes several retinal degeneration disease. In order to fabricate the suitable carrier for RPE transplantation, the hybrid poly(lactide-co-glycolide) (PLGA) film with hesperidin was prepared. Hesperidin has an anti-inflammatory and antioxidant characteristics. ARPE-19 was seeded on hesperidin/PLGA film and then, cell proliferation was determined by the MTT assay, and cell adhesion and cell morphology were confirmed by SEM. Also, RT-PCR was performed to confirm the expression of the specific genes, and AEC immunohistochemical staining was performed to determine the expression of RPE65. As a result, we confirmed that attachment, proliferation and phenotype maintenance of RPE cells were more excellent on hesperidin/PLGA film than PLGA film, thereby we were able to confirm the potential applications of hesperidin/PLGA film as tissue engineering carrier for regeneration of retina.

• Korean Journal of Veterinary Research
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• v.53 no.2
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• pp.137-141
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• 2013

To report retinal image of in a 6-year-old male castrated poodle dog with a 2-month history of nyctalopia using optical coherence tomography (OCT). Ocular reflexes were present in both eyes and slit lamp examination showed anterior subscapular cataract in the right eye. There were fundus abnormalities in both eyes similar to retinal degeneration. Scotopic electroretinograms (ERGs) revealed significantly subabnormal amplitudes and prolonged implicit time, whereas photopic ERGs were better maintained, although far from normal. OCT of affected dogs revealed generalized retinal thinning much more than a normal age-matched dog. Therefore, OCT scanning is considered to be a useful method for retinal evaluation in dogs with retinal degeneration.

• Proceedings of the Korea Information Processing Society Conference
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• 2024.05a
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• pp.580-581
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• 2024

고령화 사회에 접어들면서 황반 변성과 당뇨 망막 병증 등 시야결손을 동반하는 안구 질환의 발병률은 증가하지만 이러한 질환의 조기 발견에 인공지능을 접목시킨 연구는 부족한 실정이다. 본 논문은 안구 질환 자가 검사용 인공 신경망을 학습시키기 위한 데이터 베이스 구축 방법을 제안한다. MNIST와 CIFAR-10을 합성하여 중첩 이미지 데이터셋인 G-Dataset을 생성하였고, 7개의 인공신경망에 학습시켜 최종적으로 90% 이상의 정확도를 얻음으로 그 유효성을 입증하였다. G-Dataset을 안구 질환 자가 검사용 딥러닝 모델에 학습시켜 모바일 어플에 적용하면 사용자가 주기적인 검사를 통해 안구 질환을 조기에 진단하고 치료할 수 있을 것으로 기대된다.

• Journal of Korean Clinical Nursing Research
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• v.27 no.1
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• pp.54-65
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• 2021

Purpose: The purpose of this study was to identify influencing factors on vision-related quality of life in patients with retinal diseases receiving intravitreal injections by examining relationships among anxiety, depression, coping, eye health behaviors and vision-related quality of life. Methods: One hundred and five outpatients who were diagnosed with macular degeneration and diabetic retinopathy were recruited from one university hospital during August 16, 2019 to March 25, 2020. Data were analyzed using descriptive statistics (frequency and percentage, mean, standard deviation), and t-tests, ANOVA, Scheffé test, Pearson's correlations, and stepwise multiple regressions using the IBM SPSS Statistics 25.0. Results: The vision-related quality of life according to general characteristics of retinal disease patients with intravitreal injection showed significant differences in age (F=3.01, p=.034), subjective economic status (F=5.83, p=.004), types of retinal disease (t=2.62, p=.010), and disease in both eyes (t=-3.04, p=.003). The vision-related quality of life showed a significant positive correlation with age (r=.24, p=.012), and negative correlations with anxiety (r=-.66, p<.001), depression (r=-.48, p<.001), and emotion-focused coping (r=-.20, p=.036). The hierarchical regression analysis indicated that factors affecting vision-related quality of life in patients with retinal diseases were anxiety and subjective economic status, accounting for 47.0% of the variances of the vision-related quality of life. Conclusion: Based on our results, health professionals need to pay attention to patients with low socioeconomic status due to frequent treatments. Also, a program needs to be developed to decrease anxiety for outpatients receiving intravitreal injections to improve their vision-related quality of life.