• Journal of Korean Ophthalmic Optics Society
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• v.8 no.1
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• pp.35-39
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• 2003

The display technology on the retina is the key role in inspecting the condition of the patients. 2-dimensional retina image is widely used in the eye examination as of today. Recently, 3-dimensional retina image ones have been introduced to this area, but the quality of the image is not fully satisfied to the operator. For the purpose of developing 3-D retina imaging instrument, the optimization of a 3-D retina imaging system using Code-V tool was investigated in this thesis. He-Ne laser having the wavelength 632.8 nm was used to make a power source to detect the retina. Several lenses and mirrors installed on sledge which were developed to perform focus control on 3-D device were designed to make a beam focusing and direct line. Polygon scanner having 24 mirror facets and galvanometer making tilting movement were utilized to make a 2-D laser plane. Also, design of eye ball had been fulfilled to see the focus of the 2-D plane. Reflected ray from retina detected on the sensor array with the same path. All cognitive components were optimized for aberration correction in order to focus on retina. Results of optimization were compared to those of initial designed optics system. On the basis of above results, the result of third aberration has been corrected to stable values to the optical system. MTF evaluating the resolution of an image has been closely correlated to the diffraction limit and PSF indicating the strength distribution of an image has shown the SR value as 0.9998 having high performance. The possibility of new and powerful 3-D retina image instrument was verified by simulating each component of the instrument by Code-V.

• Progress in Medical Physics
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• v.15 no.4
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• pp.228-236
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• 2004

Retinal ganglion cells transmit visual scene as an action potential to visual cortex through optic nerve. Conventional recording method using single intra- or extra-cellular electrode enables us to understand the response of specific neuron on specific time. Therefore, it is not possible to determine how the nerve impulses in the population of retinal ganglion cells collectively encode the visual stimulus with conventional recording. This requires recording the simultaneous electrical signals of many neurons. Recent advances in multi-electrode recording have brought us closer to understanding how visual information is encoded by population of retinal ganglion cells. We examined how ganglion cells act together to encode a visual scene with multi-electrode array (MEA). With light stimulation (on duration: 2 sec, off duration: 5 sec) generated on a color monitor driven by custom-made software, we isolated three functional types of ganglion cell activities; ON (35.0$\pm$4.4%), OFF (31.4$\pm$1.9%), and ON/OFF cells (34.6$\pm$5.3%) (Total number of retinal pieces = 8). We observed that nearby neurons often fire action potential near synchrony (< 1 ms). And this narrow correlation is seen among cells within a cluster which is made of 6～8 cells. As there are many more synchronized firing patterns than ganglion cells, such a distributed code might allow the retina to compress a large number of distinct visual messages into a small number of ganglion cells.

• Journal of The Korean Ophthalmological Society
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• v.59 no.12
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• pp.1160-1165
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• 2018

Purpose: To evaluate the availability of ultra-wide field fundus photography based on eye steering technique to diagnose retinal breaks in patients with symptomatic posterior vitreous detachment (PVD). Methods: The medical records of patients with symptomatic PVD were reviewed. Retinal breaks were independently identified using four eye steering capture images of ultra-wide field fundus photographs. The sensitivity and specificity of eye steering capture imaging for diagnosing retinal breaks were calculated. Results: A total of 94 eyes of 94 patients were included. Using fundus examination after pupil dilatation, retinal breaks were diagnosed in 42 (45%) eyes. The sensitivity of the eye steering capture imaging was 98% (95% confidence interval [CI]: 88-100%), and the specificity was 98% (95% CI: 90-100%). Of the 58 retinal tears, 28 (97%) involving the superior quadrant, 10 (100%) involving the inferior quadrant, 6 (100%) involving the nasal quadrant, and 13 (100%) involving the temporal quadrant were identified using eye steering capture images. Conclusions: Ultra-wide field fundus photography based on eye steering technique was useful for diagnosing retinal breaks in patients with symptomatic PVD. However, eye steering photography could not adequately replace the fundus examination after pupil dilatation in all cases.

• The Korean Journal of Vision Science
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• v.20 no.4
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• pp.421-429
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• 2018

Purpose : We identified correlation between macular thickness and RNFL (retina nerve fiber layer) measured by OCT and axial length in Korean children divided as three groups according to refractive errors. Methods : In total, 134 eyes of 67 Korean children who experienced no eye disease and ophthalmology surgery were involved in this study and then divided as three groups such as hyperopic, emmetropic and myopic groups. Macular thickness and RNFL thickness were measured with Cirrus HD-OCT, and axial length was done with IOL Master.Macular thickness and RNFL thickness were measured by Cirrus HD-OCT, and axial length using IOL Master. Correlation between axial length and retinal thickness in three groups according to refractive errors was investigated. Results : The type of refractive error measured by axial length was myopic, emmetropic and hyperopic groups in order, showing significant difference (p<0.05). The center thickness of macular was myopic, emmetropic and hyperopic groups in order, showing significant difference(p<0.05). The thicknesses of superior, nasal and inferior regions in peripheral macula were the thinnest in myopic group (p<0.05). It was shown that positive correlation was found between the center thickness of macula and axial length (r=0.283, p<0.05), while negative correlation was found between the peripheral thickness of RNFL and axial length. The temporal thickness of RNFL represented the thickest in myopic group, showing positive correlation with axial length(r=0.39, p<0.05). The superior, nasal and inferior thickness of RNFL represented negative correlation with axial length, showing statistically significant in the nasal thickness of RNFL(r=-0.23, p<0.05). Conclusion : Through this study, we identified correlation between macular thickness, the thickness of RNFL and axial length using OCT in Korean children, and also found the differences in three refractive error groups.

• 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.

• The Monthly Diabetes
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• s.255
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• pp.18-21
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• 2011

당뇨병에 걸리면 조심해야 할 눈에 오는 합병증 중 가장 흔한 것은 망막병증이고, 이 망막병증이 계속 진행되면 녹내장이 발생할 수 있다. 그런데 녹내장은 눈의 구조와 기능을 손상시켜 결국에는 실명에 이르게 할 수 있는 질환이라 주의해야 한다. 녹내장의 발견에서부터 진행과정, 예후 등을 한국녹내장관리협회 정상갑 회장과의 인터뷰로 자세히 알아보자.

• RED RIBBON
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• s.66
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• pp.14-15
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• 2005

거대세포바이러스(cytomegalovirus, CMV)는 헤르페스바이러스에 속하는 바이러스이다. 대부분의 성인이 CMV를 보유하고 있으나, 면역 기능이 정상인 사람에서는 CMV로 인한 질병이 발생하지 않는다. 하지만 에이즈 환자, 장기이식환자, 골수이식환자 등과 같이 면역 기능이 저하된 환자에서는 CMV에 의한 폐렴, 망막염, 장염 등의 질병이 발생할 수 있다.

• The Korean Chronic Disease News
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• no.94
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• pp.6-7
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• 1988

중년 이후에는 대부분의 사람이 생리적인 노화현상의 일환으로 시력의 사용에 불편을 느끼게 되며 때로는 중년이후에 잘 발생하는 질환에 의하여, 심한 시력장애를 일으키는 수도 있다. 전자의 경우에는 노안, 비문증 등을 들 수 있고 후자의 경우는 백내장, 당뇨병성망막증, 망막정맥폐쇄증, 황반부 변성등을 들 수 있다.

• 대한핵의학회:학술대회논문집
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• 1985.05a
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• pp.159.2-160
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• 1985

• The Monthly Diabetes
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• s.259
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• pp.36-37
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• 2011

당뇨병성 망막병증은 가장 흔한 합병증으로 당뇨병을 앓은 기간이 길고, 혈당조절이 잘 안 되면 발생하기 쉽다. 일단 발병하면 치료해도 정상으로 돌아갈 수 없고 심하면 실명하게 되므로 무엇보다도 예방이 중요한 질환이다. 이에 당뇨관리를 대제로 하지 않고, 치료시기를 놓쳐 오른쪽 눈이 실명한 안정희씨와 그의 가족을 만나 인터뷰해보았다.