• Applied Microscopy
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• v.44 no.3
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• pp.88-95
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• 2014

This study examined the effects of quercetin on corneal opacity caused by corneal edema by suppressing the damage on corneal endothelial cell, which was induced by mitomycin-C (MMC). In the MMC-treated group, the number of keratocytes was noticeably fewer compared to that of other groups. Although this group showed normal amount of fiber in the corneal stroma, the thickness was shown to be very thick and the alignment of the corneal endothelial cells that worked as the barrier against aqueous humor was irregular. According to such results, it was known that corneal opacity induced by MMC is not caused by proliferation of keratocytes, but by corneal edema triggered by the infiltration of aqueous humor. In the MMC+quercetin and quercetin+MMC-treated groups, the number of keratocytes was higher and polymorphonuclear leukocytes infilteration was lower significantly compared to that of the MMC-treated group. Although the amounts of fiber and endothelioid cell arrangement were normal, there was more space observed in the corneal stroma. Nonetheless, these groups showed significantly lower stromal thickness compared to that of the MMC group. In conclusion, quercetin has the effect on the reduction of corneal opacity caused by corneal edema that work MMC-induced damage to the corneal endothelial cells.

• Journal of Korean Clinical Health Science
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• v.2 no.3
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• pp.203-208
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• 2014

Purpose. To analysis the refractive error in 7-9 year-old Korea children. Methods. From July 2013 to June 2014, two hundred eighty two subjects were performed in refraction test using the Auto-Refractometry. Results. The refractive error by spherical equivalent among all subjects was myopia 47.58%, emmetropia 42.35%, astigmatism 32.33%, and hyperopia 8.76%. Myopia was more common in female than males although the difference was not statically significant. The axis of astigmatism was with the rule in 65%, against the rule in 31.5%, and oblique in 3.5% There was a statistical significance between 7 year and 9 year of male in the spherical equivalent power(p=0.010). Also there was a statistical significance between 7 years and 9 years of female in the spherical equivalent power(p=0.036). However, there was not a statistical significance between male and female in spherical equivalent power(p>0.5). Conclusions. In this study, myopia was the most common refractive error. On the other hand, The prevalence of the axis of astigmatism was the with- the- rule. The spherical equivalent of refractive error was similar results between male and female. However The refractive error was different style with aging. these data suggested that the analysis of the refractive error at young children can provide the information of useful diagnosis for the correction of visual acuity.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.7
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• pp.1646-1652
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• 2015

In this paper, we propose a depth conversion method for orthoscopic real image reconstruction in integral imaging. Pseudoscopic image has been regarded a problem in conventional integral imaging. the depth of reconstructed image is depending on a coordinate of an elemental image. The conversion from pseudoscopic to orthoscopic may be possible by analysing the geometrical relation between pickup and reconstruction system of elemental image. The feasibility of the proposed method has been confirmed through preliminary experiments as well as ray optical analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.6
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• pp.2190-2195
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• 2010

In order to examine whether the accommodative trainings with push-up or flipper methods induce the decrement of near addition on early presbyopia aged in 40s having less than 1.00 D addition, daily home vision training was performed for 12 weeks. We evaluated accommodative amplitude, accommodative facility, relative accommodation, and presbyopic addition at every one week. Two accommodative trainings significantly decreased the presbyopic addition as a degree from 0.125 D to 0.375 D, and push-up training was more effective than that of flipper training. Both push-up and flipper trainings are an useful methods to decrease the near addition of early presbyopia as an improvement of the accommodative amplitude.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.3
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• pp.59-63
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• 2007

This study examined prevailing parents' knowledge of eye health for young children. 139 mothers responded to a questionnaire developed by the researchers. Mothers had general eye health knowledges regardless of their age, education level, and job, but they had less knowledges about children's eye health in some items. Therefore there is a need to develop education programs and materials for eye health as well as a need to provided for young children's parents.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.4
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• pp.457-469
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• 2014

Purpose: This study was to evaluate students and optometrist in the importance and difficulty of work capability, and the educational needs for optometric duty in order to use them as basic data for the improvement of the curriculum. Methods: 292 ophthalmic optic's college students and 123 optometrists were surveyed in the importance and difficulty of work capability, and the educational needs for the optometric duty, and data was statistically analyzed for the results. Results: The mean of the importance of work capability was higher for the optometrists (3.61) than for the students (3.51) and glasses dispensing was the highest for both students and optometrists. The mean of the difficulty of work capability was higher for the students (2.75) than for the optometrists (2.67), which was the highest in refraction for the students and in prescription for the optometrists. The mean of educational needs was higher for the optometrists (3.53) than for the students (3.45), which was the highest in glasses dispensing for the students and highest in refraction for the optometrists. There were significant differences in some tasks in between the students by gender, grade and desired working place, while between the optometrists by gender, age, work experience, working place and working area (p<0.05). Conclusions: It is necessary to improve a curriculum of the Department of Opthalmic Optics, and develop a standard curriculum reflected the importance and the difficulty of work capability, and the educational needs regarding to optometric duty.

• Journal of dental hygiene science
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• v.21 no.3
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• pp.178-184
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• 2021

Background: As the importance of the esthetic function of teeth increases, the use of esthetic restoration materials and whitening treatment are increasing. The purpose of this study was to investigate the color change of esthetic restoration materials upon using staining and whitening toothpaste. Methods: Light curing (LC) packable composite resin, LC flowable resin, LC glass ionomer (GI), and self-curing GI specimens were colored in coffee or curry for three hours a day for seven days. After that, regular toothpaste, whitening toothpaste containing hydrogen peroxide, and whitening toothpaste containing activated charcoal were applied for three minutes three times a day for two weeks. Luminosity (L), chromaticity a (a), and chromaticity b (b) were measured using a spectrophotometer once a week. Results: In the coffee-colored group, the change in L^2*a^2*b² (E²) with time was significant (p=0.004), there was no difference for different toothpaste types (p=0.646), and there was significant difference (p<0.001) for different esthetic restorative materials. The change of E² in the curry-colored group was significant only for different esthetic restorative materials (p<0.001). In the coffee-colored group, the L, a, and b values of the light-curing GI showed greater change than other materials after staining and one week after whitening, turning dark, red, and yellow. In the curry-colored group, L did not differ for different materials and times, and a and b showed the greatest difference in light-curing GI after staining and one and two weeks after whitening. Conclusion: The use of whitening toothpaste for two weeks was not different from the use of general toothpaste in the removal of staining or whitening. Since light-curing GI is the most vulnerable to coloration, it is recommended that coloring by food chromogen should be explained in advance, before using light-curing GI for teeth restoration.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.1
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• pp.81-86
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• 2009

Purpose: We developed the MYSTERY CIRCLE vision training program which was suitable for Korean people. We compared it with the established programs, Block string and Anaglyphs in aspect of functional, sensory, and symptomatical changes of binocular vision. Mehtods: The vision training observation group included 75 clients (male=40, female=35) who had binocular vision disorders without opthalmic diseases or vertical phoria. Results: According to the results, all training methods showed improvement of binocular vision function, sensation and symptoms. But the Block String had low participation, reference rate of subjects and success rate and showed the different degree of improvement depending on individuals. Anaglyphs method showed high participation and improvement. But it had a low degree of success rate and preference rate. Conclusions: MYSTERY CIRCLE method showed the highest participation, reference rate of subjects, success rate, and high degree of improvement. Therefore we suggest that MYSTERY CIRCLE is an effective and alternative method for binocular vision disorder therapy.

• Journal of Korean Clinical Health Science
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• v.10 no.1
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• pp.1553-1558
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• 2022

Purpose: The aim of this study was to determine the association between stigmatism and amblyopia. Methods: It was a hospital based, cross-sectional retrospective study conducted in Nepal Eye Hospital. Medical record of amblyopic children aged 13 years or younger from were reviewed. Children with amblyopic eyes due to simple astigmatism were included. Relation between depth of amblyopia with magnitude and types of astigmatism, orientation of axis was determined. Out of 139 amblyopic eyes of 82 children, 93 were simple myopic astigmatism and remaining 42 were simple hyperopic astigmatism. Results: Mean age of patients was 7.38±2.61 years. Visual acuity improved by at least one line in Snellen chart in 4/5th of eyes after astigmatic correction. Moderate amblyopia was found to be present in 45% eyes while severe amblyopia in 16% of eyes. With the rule astigmatism was found to be present in 88% eyes. Mean astigmatism was 2.47±0.98D and majority of eyes (67.7%) had high astigmatism. Depth of amblyopia was not associated with magnitude of astigmatism (p > 0.05) but number of lines improved with astigmatic correction was correlated with the magnitude of astigmatism (p < 0.001). Risk of amblyopia is more in high myopic astigmatism. Conclusion: Presenting age of amblyopic children was late in Nepal. Depth of amblyopia was not associated with magnitude of astigmatism.

• Korean Journal of Materials Research
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• v.24 no.12
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• pp.652-657
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• 2014

The purpose of this study was to investigate the microstructures and mechanical properties of zirconia toughened alumina (ZTA) ceramics prepared from two kinds of 3Y-TZP powders. ZTA composites were prepared by adding two kinds of 3Y-TZP powders, 3YEH (BET = $7m^2/g$) and 3YEM (BET = $16m^2/g$), to ${\alpha}$-alumina in the range of 5-25 wt%. It was found that the microstructure photographs of the ZTA composites showed that the average grain size of alumina decreased as the content of zirconia increased. In our present study, specimens containing 3YEM zirconia exhibited smaller grain sizes compared to those of 3YEH zirconia. The Vickers hardness of the ZTA composites that were sintered at $1600^{\circ}C$ for 2 hrs was found to smoothly decrease with increasing zirconia content because of the low Young modulus in zirconia. The Vickers hardness of the ZTA containing 3YEH zirconia was greater than that of the 3YEM zirconia. In substance, the fracture toughness ($K_{1c}$) of the ZTA composites increased as the content of zirconia increased. The fracture toughness ($K_{1c}$) of ZTA containing 3YEM zirconia was greater than that of 3YEH zirconia.