• Journal of Korean Ophthalmic Optics Society
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• v.5 no.1
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• pp.107-116
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• 2000

This study is of investigation of refraction error, spectacles and contact lenses wearing state, visual acuity test, ophthalmologic common sense and vision care, using questionnaire study for 850 male and female high school students in Kunsan and Chongup City, Cheolla North Province. The results are as follows: 1. Among the 823 answerers, emmetropia is 18%, myopia is 55.1%, and hyperopia is 7%, respectively. 2. Among the 837 answerers, 381 students(45.5%) wear spectacles or contact lenses. Among the 381 students who wear spectacles or contact lenses, 78% wear only spectacles, 4% wear only contact lenses and 18% wears spectacles sometimes or contact lenses sometimes. 3. The places where the answerers had visual acuity test to wear spectacles or contact lenses are optical shop(64.7%), hospital(28.3%), unchecked(4.2%) and the others(2.7%). The places where the answerers had visual acuity test to change their spectacles or contact lenses are optical shop(82%), hospital(28.3%), unchecked(6.6%) and the others(1.9%). 4. As for the period of visual acuity test, from 6 months to one year is 54.1%, within 6 months is 9.2%, from one year to two years is 29.5%, and more than two years is 7.2%. 5. The contact lens wearers purchased their contact lenses at optical shops(94%) and at hospital(6%). 6. The reasons why they like wearing contact lenses are their appearance(51.2%), convenience in physical excercise(23.l%), lighter weight than spectacles(9.8%) and the others(15.7%). 7. As for the spectacles frame they like, plastic frame is 24.4%, gold or silver plated frame is 43.4%, coloured frame is 32.1%. 8. As for the considerations in choosing spectacles frame, their design is 37%, their quality is 36%, their price is 14.7% and their brand is 12.5%. 9. As for the period for changing spectacles, 10.5% is within 6 months, 57.3% is 6months to 1 year, 22.4% is 1 year to 2 months and 9.6% is more than 2 years. 10. There is a false fact, in Korea, that even though one has his poor eyesight, not wearing custom is helpful for the eyesight recovery. As for their conviction of the false fact, 10.5% of the answerers have 100% conviction, 22.5% of them have 22.5% conviction, 49.5% of them have 50% conviction and 17.5% of them don't have any conviction. 11. 48.5% of the answerers are interested in their vision care while 51.5% of them are not interested at all. As for the way of vision care, the vision-care way to keep enough distant when they are watching TV, when they are using computers and when they are reading, is 49% while the vision-care way such as hypogastric breathing or eye massage is 11%. And alimentotherapy is 4% and the rest who are not interested in vision care is 36%. 12. When they come to an age, the students who want vision correction operation are 45.9% while the students who do not want it are 27%. The students who do not have any idea about the operation are 27.1%

• Journal of Korean Society of Forest Science
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• v.82 no.1
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• pp.26-33
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• 1993

In vitro shoot proliferation and rooting were tested for 2-0 seedlings of half-sib families of 4 plus oaks trees. Nodal segments having axillary buds from 37 families(16 of Quercus acutissima, 10 of Q. variabilis, 7 of Q. serrata, and 4 of Q. mongolica) were cultured on WPM(Woody Plant Medium) supplemented with 0.5 mg/l BA (6-benzyladenine) and 0.01 mg/l NAA(${\alpha}$-naphthalene acetic acid) and subcultured at 2-3 weeks of intervals fur 6 months. In vitro rooting was carried out on GD(Gresshoff and Doy) medium supplemented with 0.5mg/l IBA(indole butyric acid). The capacity for shoot proliferation and rooting was highly varied with families. Generally, white oaks(Q. serrata and Q. mongolica) showed poor response than black oaks(Q. acutissima and Q, variabilis) in shoot proliferation and rooting. Among the total of 37 families, 7 of Q. acutissima, each 2 of Q. variabilis, Q. serrata, and Q. mongolica revealed abilities for continuous shoot proliferation, and the others failed to proliferate. Rooting of the selected oak trees also greatly varied among the families. In Q. acutissima, rooting ratio ranged from 10.0%(CB 25. KG 4) to 89.8%(CB 18). Although 26.7% of KG 16 in Q. variabilis, 3.3% of JN 15 in Q. serrata were rooted, Q. mongolica was not rooted at all in this experimental conditions. No relationship between shoot growth and the rooting ability was observed. Present results suggest the possibility of large-scale micropropagation, but further studies on family differences, shoot-tip necrosis, and callusing of rooting junction are still required to develop reliable micropropagation systems.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.2
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• pp.145-150
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• 2010

Purpose: In this study we investigated the correlation between the effect of myopia correction and the change of corneal eccentricity using reverse geometry lens. Methods: The 23 students (46 eyes) continuously wearing reverse geometry lens during 3 months were divided into Group I and Group II by different parameter fitting methods of wearing Reverse Geometry Lens. We measured a corneal eccentricity for Group I and Group II at $10^{\circ}$, $20^{\circ}$, and $30^{\circ}$ positions from corneal apex before wearing reverse geometry lens, 1 week, 1 month, and 3 months after wearing reverse geometry lens. We also measured an uncorrected visual acuity, a spherical equivalent, and a corneal radius and analyzed the correlation between them and the change of corneal eccentricity using statistical significance test. Results: There were the statistical significances of a change of corneal eccentricity (p=0.03, t=-2.29) for Group I and Group II at 10 position from corneal apex in a week after wearing reverse geometry lens, but were not those (p>0.05) in 1 month, and 3 months after wearing reverse geometry lens. There were the statistical significances of correlation between the change of corneal eccentricity and a corrected visual acuity, and a corneal radius, respectively. Particularly, the high correlation between the change of corneal eccentricity and a corrected visual acuity (r=-0.36, p=0.00, t=6.5), and a spherical equivalent (r=-0.72, p=0.00, t=-70.5) for Group II in a week after wearing reverse geometry lens showed. Conclusions: We knew from these results that the high correlation between the effect of myopia correction and the change of corneal eccentricity in a week after wearing reverse geometry lens represented.

• Journal of Korean Ophthalmic Optics Society
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• v.21 no.3
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• pp.259-264
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• 2016

Purpose: To establish the cause of decrease in body stability and to analyze the effects on sensory organs maintaining static balance according to the induced astigmatic blur. Methods: Twenty subjects (10 males, 10 females; mean age, $23.40{\pm}2.70years$) were participated in this study. To induce myopic simple astigmatism, the axis directions of cylindrical lenses were placed $180^{\circ}$ on both eyes (with-the-rule), $90^{\circ}$ on both eyes (against-the-rule), and $45^{\circ}$ on both eyes (oblique). Cylindrical lenses of +0.50, +1.00, +1.50, +2.00, +3.00, +4.00, and +5.00 D were used to increase astigmatic blur in each astigmatism types. General stability (ST) and sway power (SP) in frequencies by each sensory organs were analyzed using the TETRAX biofeedback system. Results: ST in the all astigmatism types were raised with increase of astigmatic blur compared to full corrected condition, but a significant difference only showed in the induced oblique astigmatism. According to the results of correlation analysis between ST and SP in the each frequencies with increase of astigmatic blur, the causes of increased ST in the induced oblique astigmatism showed to have a high correlation in order of somatosensory system (high-medium frequency), central nervous system (high frequency), peripheral vestibular system (low-medium frequency), and visual system (low frequency). Conclusions: The visual information by uncorrected oblique astigmatism may disturb the normal functions of all sensory organs maintaining body balance, consequently, the body stability can be reduced. Therefore, optimal correction of astigmatism can play an important role for reducing the instability of body balance.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.4
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• pp.111-117
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• 2007

The visual evoke potential(VEP) is the effective method to diagnose and treat the amblyopia or to check the infants visual ability. In order to evaluate the changes of P100 latencies and amplitudes of VEP by intensity of illumination and refractive errors, we measured latencies and amplitudes of 41 normal adults (20/20 VA) who have no ocular diseases and neurologic diseases. The results were as follows: In the scotopic condition, the latencies were N75$75.83{\pm}3.69$ msec, P100$103.48{\pm}5.34$ msec, the P100 amplitude was $14.86{\pm}2.43$ msec, and in the photopic condition, the latencies were N75$76.71{\pm}3.11$ msec, P100$107.26{\pm}5.54$ msec and the P100 amplitude was $10.35{\pm}1.75$ msec. The latencies and amplitudes of P100 in the photopic condition had higher values than those in the scotopic condition and the measures were significantly different between the scotopic and photopic condition (p<0.01). The P100 latencies were delayed both in the scotopic and photopic condition with the refractive errors and those measures were delayed more than in the photopic condition. The P100 amplitudes in the induced myopic and hyperopic conditionsreduced than in the emmetopes in both illumination conditions. The P100 latencies and amplitudes in emmetropes showed a correlation with the induced myopic conditions in the scotopic condition. Those results showed that P100 latencies and amplitudes are dependent on the illumination conditions and refractive errors. And we suggest that those results would be useful to determine and evaluate the normal range for the person considering patients' refractive errors and illumination of the test room.

• Journal of Korean Society of Forest Science
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• v.29 no.1
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• pp.102-114
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• 1976

This experiment was conducted to investigate the percentage of fertile seed in terms of crossabilities and relationships of taxonomic affinities for the ${\times}$ P. rigitaeda of interspecific hybrid, ${\times}$ P. rigida rigitaeda and ${\times}$ P. rigitaeda rigida of backcross hybrids, $F_2$ of ${\times}$ P. rigitaeda and natural hybrid of ${\times}$ P. rigitaeda within Sub-genus Diploxylon of the Genus Pinus. The possibility of establishment of hybrid seed orchard and differentia of hybrids for the purpose of extensive program of reforestation in the future have also been investigated. And, the experimental results obtained are summarized as follows: 1. On the basis of crossabilities as well as on the taxonomic affinities according to the systems of Shaw, Pilger and Duffield, it has been proven that the parental species of those hybrids are of close affinities and range of the fertile hybrid seed production rate was as high as 67-87% in the best hybrid combination (Table 6). 2. Those hybrids seemed to be most promising in the growth perfermance exhibiting 28-80% more volume growth compared to the P. rigida with the statistic significance of 1-5% level (Table 7, 8, 9). And all hybrids exhibit cold hardiness as much as P. rigida except $F_1$ hybrid of ${\times}$ P. rigitaeda and it seems to suggest that the characteristics of cold hardiness were transmitted from the P. rigida. 3. With regard to the anatomical characteristics of needle, the hypoderm is biform in most of the hybrid pines and the characteristics of resin canals are medial in all hybrid. And, the fibrovascular bundles are intermediate of both parent in all hybrid. Therefore it was found to be possible to distinguish the hybrids pines from their parents by the needle characteristics (Table 10). 4. It has been demonstrated that the hybrids pines have a phenolic substance (No. 7) of pale yellow at Rf-0.66, same as P. rigida, but no trace of phenolic substance was observed in the P. taeda. This fact will serve as an important criteria for early identification of hybridity in progeny testing (Table 11). 5. It was found to be possible to distinguish by the starch gel electrophoretic variations banding patterns and staining densities of isoperoxidase in the needles of the hybrids pines from their parents (Fig. 1).

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.2
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• pp.51-57
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• 2008

Purpose: This study has been conducted to know how the size and position of the circle of least confusion has an influence on the vision for minimization of asthenopia when astigmatism is corrected and appropriated prescription to provided clear vision life. Methods: The method of the study has been worked on 68 students (136 eyes) of man and woman enrolled in university of Gyeong-gi-do aged 20 to 40, who have myopic astigmatism in order to know how the corrected vision changes according to the size and position of the circle of least confusion of astigmatism, the vision has been tested by giving the vision whose astigmatic power of 0.25D and 0.50D was just reduced, low correcting the astigmatic power into 0.50D, and at the same time inserting additionally spherical power -0.25D, all under a condition that the corrected vision after completely corrected astigmatism, and the axis of astigmatism was not changed. Results: The average vision was 1.047 when the astigmatic power was fully corrected, and in low correction of 0.25D, it was 0.914, and in low correction of 0.50, it was 0.772. It has been learned that the bigger the circle of least confusion was the bigger the range of vision reduction and the corrected vision in astigmatism has correlation with the size of the circle of least confusion. It has been examined that the average vision according to position of the circle of least confusion in astigmatism was 1.047 when the astigmatic power was completely corrected and focused on the retina with state of point, and in case that the astigmatic power was 0.50D of state of low correction, that is, the circle of least confusion was focused before retina, it was 0.828, and it was also 0.826 when the astigmatic power is low corrected with 0.50D and the circle of least confusion was focused on the retina. Explained briefly, It has been examined that in case that the state of low correction of the astigmatic power was same, the vision reduction was less in the image of the circle of least confusion focused upon the retina than in the image of its being focused before the retina. Conclusions: In case that the refractive power of cylindrical lens is reduced in test of wearability in astigmatism, there needs surely an adjustment of spherical lens that can place the circle of least confusion on the retina.

• Journal of Preventive Medicine and Public Health
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• v.30 no.3 s.58
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• pp.567-576
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• 1997

To evaluate the effects of reflected glare on eyes, authors assessed the periodic health examination(1991-1996) & self-administered questionnaire data of a semiconductor producing company. The 13 lead frame(LF) department workers have been exposed to high reflected glare in the process for examining the silver plating products. We compared the data of connector(14) and clerical(12) workers as the non-exposed ones. Among LF department workers, 100% felt their visual acuity worsened(connector:81.8%, clerical:85.7%), and 70% had worn the glasses o. contact lenses(connector : 14.3%, clerical :40%) since working at the company. Major ophthalmic symptoms of the LF workers are asthenopia, tearing, decreased visual acuity, congestion and glare. Decrease of visual acuity by Hahn's line change of the LF workers is significantly high during a 5-year follow-up(p<0.05 by simple regression) compared with connector clerical workers.

• Journal of Korean Society of Forest Science
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• v.76 no.4
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• pp.370-375
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• 1987

This study was conducted to examine the position effect of axillary buds on shoot multiplication and rooting with 1-year-old seedlings of Quercus acutissima. Shoot multiplication was greatly affected by axillary bud position: Productivity of multiple shoots were decreased in the order of top, mid and basal explants respectively. The best shoot multiplication (mean 6.1 shoots per explant) was obtained on WPM medium containing $1.0mg/{\ell}$ BAP and $0.1mg/{\ell}$ NAA using basal explant after 4-week-culture. Rooting was also greatly influenced by position. Its percentage was increased in the order of top, mid and basal explant respectively. Root initiation was better and more rapid on 1/2MS medium than GD medium. High rooting percentage (100%) was obtained on 1/2MS medium containing $0.2mg/{\ell}$ IBA after 15 days culture. Sucrose concentrations did not effect on rooting. However root development and shoot growth were greatly affected by them. Root was developed shortly on 1-2% levels and shoot growth was getting retarded, whereas both of them did not show significant difference at 3-6% levels. Rotting was decreased on 7-8% levels gradually, but shoot and leaf condition was better than any other concentrations. Survival rate of rooted explants in pot was varied according to the position of explants. Seedlings of top part were survived up to about 50% but most of mid and basal part seedlings did not survive over 4 weeks even in high humidity condition. Seedlings in pots showed normal growth over 10 months but most of them showed the condition of premature leaf shedding.

• Journal of The Korean Ophthalmological Society
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• v.59 no.12
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• pp.1129-1136
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• 2018

Purpose: To compare the postoperative clinical outcomes after cataract surgery and implantation using the BunnyLens $MF^{(R)}$ and $ReSTOR^{(R)}$ multifocal intraocular lenses. Methods: Sixty-five eyes implanted with multifocal intraocular lenses were divided into two groups involving either $ReSTOR^{(R)}$ (39 eyes) or BunnyLens $MF^{(R)}$ (26 eyes) lenses. In these two groups, the distant and near visual acuity, astigmatism, spherical equivalent, and contrast sensitivity test were examined at preoperative and postoperative 1 week, 8 weeks, and 24 weeks. We compared the clinical efficacy between the two groups before and after cataract surgery using statistical analysis. Results: The mean value of distant and near visual acuity, and spherical equivalent of both groups after intraocular lens implantation were significantly improved, compared with the preoperative values (p < 0.05), while there was no significant differences between the two groups (p > 0.05). The means of postoperative distant and near visual acuity, astigmatism, and contrast sensitivity test were not significantly different between $ReSTOR^{(R)}$ and BunnyLens $MF^{(R)}$ lenses (p > 0.05). The mean numeric error of spherical equivalent at the final postoperative 24 weeks was $-0.17{\pm}0.50$ diopters (D) for the $ReSTOR^{(R)}$ lenses and $-0.34{\pm}0.52D$ for the BunnyLens $MF^{(R)}$ lenses (p > 0.05). Conclusions: BunnyLens $MF^{(R)}$ and $ReSTOR^{(R)}$ lenses showed no significant difference in clinical efficacy, including distance and near vision, spherical equivalent error, and contrast sensitivity test after cataract surgery. However, it should be noted that BunnyLens $MF^{(R)}$ lenses had a tendency toward myopic shift compared with $ReSTOR^{(R)}$ lenses.