• PNF and Movement
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• v.17 no.1
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• pp.57-68
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• 2019

Purpose: This study is an investigation of the effects of long-term smart phone usage and of stretching on muscle stiffness, concentration, and visual acuity. Methods: Forty healthy young adults voluntarily participated in the study and were measured for muscle stiffness, concentration, and visual acuity before smartphone usage and after 30 minutes, 60 minutes, and 90 minutes of smartphone usage. The participants were randomly allocated to the intervention group (n=20) and the control group (n=20). Five minutes after the stretching exercise and eye exercise intervention, the participants were remeasured. Results: After long-term smartphone usage, increases in muscle stiffness and concentration were statistically significant (p<0.05), whereas decreases in visual acuity were statistically significant (p<0.05). After the stretching exercise and eye exercise intervention, muscle stiffness significantly decreased (p<0.05) and visual acuity significantly increased (p<0.05). Concentration, according to the stretching exercise and eye exercise intervention, showed no significant pre- or post-test difference. Conclusion: The results from this study indicate that long-term smartphone usage effectively improved concentration but increased muscle stiffness and decreased visual acuity. Appropriate stretching and eye movement during long-term smartphones usage should mitigate the effects on muscle stiffness and visual acuity. Furthermore, smartphones should be considered an effective tool for concentration training when coupled with the development of appropriate applications.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.15 no.2
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• pp.200-209
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• 2002

Visual acuity Decrease is one of the most common symptoms of adolescents. Acupuncture method has been used for improvement of visual acuity from ancient period. But it is not sufficent to recognize underlying causes and predisposing factors of visual acuity decrease. So we investigate the common causes and factors on myopia outpatients group. We researched 992 outpatients who were treated at Department of Acupuncture & Moxibustion, National Medical Center from June 2001 to May 2002. The outpatients were classified into several groups according to visual acuity and age. Common predisposing factors of visual acuity decrease were assessed through questionnaires based on the Classics of the traditional oriental medical bibliography. The results are as follows; age distribution is 52.9$\%$ for female, 47.1$\%$ for male. The predisposing factors were ranked as poor posture(66.9$\%$), unbalanced diet(57.2$\%$), heredity(53.8$\%$), irregular diet habit(51.3$\%$) and so on. These results playa role as preliminary data in recongnition of myopia in the view of oriental medicine.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.3
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• pp.43-49
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• 2009

Purpose: The purpose of this study was to obtain the fundamental data of dynamic visual acuity and dynamic stereoacuity. Methods: The subjects were 20 athletes (high school baseball player) and 40 nonathletes (20 male, 20 female). We assessed static visual acuity, dynamic visual acuity, static stereoacuity and dynamic stereoacuity using rotating mirror projection system and computer program. Results: Three groups had similar static visual acuity and static stereoacuity. On the other hand, the dynamic visual acuity and dynamic stereoacuity showed statistically significant differency. The mean dynamic visual acuity for athletes was 174.80${\pm}$28.70 deg/sec, 137.10${\pm}$16.54 deg/sec for male nonathletes and 111.59${\pm}$15.40 deg/sec for female nonathletes. The mean dynamic stereoacuity for athlets was 234.55${\pm}$19.64, 249.05${\pm}$8.86 for male nonathletes and 247.10${\pm}$14.89 for female nonathletes. The group of athletes had better dynamic visual acuity and dynamic stereoacuity. Conclusions: If the result of this study apply to sports, it will be very useful to improve sports performance.

• Journal of Korean Ophthalmic Optics Society
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• v.16 no.2
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• pp.167-170
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• 2011

Purpose: This study was tried whether expectation of astigmatism from spherical equivalent visual acuity was possible. Methods: For 54 men and women (108 eyes) corrected to emmetropia, average age of 23.3, changes of visual acuity (5m) were measured with an increasing the powers at every ${\pm}$0.25D when the (-) axis of cross cylinder is $180^{\circ}$, $90^{\circ}$, and $45^{\circ}$, respectively. Results: As the power of cross cylinder was increased, visual acuity was decreased. When the powers of cross cylinder were ${\pm}$2.50D ($180^{\circ}$ and $90^{\circ}$) and ${\pm}$2.25D ($45^{\circ}$), visual acuity was 0.05 which is the minimum measurement possible. Conclusions: The diagram on astigmatism dealing with each spherical equivalent visual acuity was able to tabulate.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.2
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• pp.95-106
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• 2007

The purpose of this study was to investigate effect of spectacle correction therapy instead of occlusion therapy for refractive amblyopia treatment. Spectacle correction were prescribed to give the same effect as a occlusion therapy by under correction for normal eye and there was no additional treatment but only spectacle correction for hyperopic amblyopia. The results can be summarized as follows: 1. In hyperopic amblyopia after correction, initial visual acuity($Mean{\pm}SD$) was $0.36{\pm}0.13$ and final visual acuity($Mean{\pm}SD$) was $0.82{\pm}0.23$. 2. Regardless with age, there was significant differences between initial acuity and final acuity, it shows improvement in visual acuity after spectacle correction treatment. 3. Initial correction age did not influence the length of treatment and success rate of treatment, so that ambyopia correction effect not related with age. 4. Compared with initial visual acuity with final visual acuity, initial visual acuity was in proportion to final visual acuity. 5. Incidence was higher in hyperopia and hyperopic astigmatism than myopia and myopic astigmatism in refractive amblyopia group and the therapy was more effective for hyperopia and hyperopic astigmatism than myopia and myopic astigmatism. 6. Treatment was effective even for children who is older than 8 years.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.9 no.1
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• pp.146-158
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• 1996

We observed 79 patients, who visited the Department of Oph. & Otorhinolaryngology in Oriental medicine of Kyung Hee University Medical Center from July 1995 to June. 1996, with the complaint of decreased visual acuity. The results were as follows. 1. In the incidence of decreased visual acuity, men's was $46.84\%$(37 cases) and women's was $53.16\%$(42 cases), which showed that more women were suffering decreased visual acuity than men. In the incidence of myopic ametropia and astigmatic ametropia among the total patients, men's was $44.62\%$(29 cases) and $37.50\%$(9 cases) each, and women's was $55.38\%$(36 cases) and $62.50\%$( 15 cases) each, which also showed that more women were suffering myopia and astigmatism than men. 2. The average age of patients was 11.08 years at the first visit. The most were the patients from 6 to 15 years old, with 63 cases($79.74\%$). 3. The age of onset in the decreased visual acuity was mainly 6∼10 years with 45 cases($56.96\%$). In the case of myopic ametropia and astigmatic ametropia, the age of onset was also mainly 6∼10 years with 65 cases($60.00\%$), and with 12 cases($50.00\%$) each. 4. In ABO blood type, the frequency was, A type, O type, B type and AB type in order. In men, O type was the most, while in women, A type. 5. In the liking for cool or warm food or tepidity, the liking for cool food was the most in both men and women. 6. The type of decreased visual acuity was mainly myopic ametropia with 65 cases($82.28\%$). Astigmatic ametropia was $30.38\%$ with 24 cases, hyperopic ametropia $2.53\%$ with 4 cases, and the decreased visual acuity accompanied by amblyopia $7.59\%$ with 4 cases. 7. At the first visit, the average visual acuity of O.D. was 0.29 and that of O.S.. 0.24, which showed that O.S.. is worse than O.D.. The visual acuity below 0.2 was the most, $63.29\%\;in\;O.D..\;72.15\%$ in O.S.. 8. In the treatment period, 4∼7 weeks occupied $35.44\%$ with 28 cases, 8∼11 weeks $30.38\%$ with 24 cases, so the treatment period was mainly these two periods with 52 cases($65.82\%$). 9. The average frequency of acupuncture treatment per week was mainly 2.1∼3.0 times with 45 cases($56.96\%$). In this case, men was 24 cases($53.33\%$) and women 21 cases($46.67\%$), so men was more than women. 10. The frequency of herbal prescription was mainly Gamijungjitang and Gamijingjibogansan with 76 cases($85.39\%$).

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.6
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• pp.155-163
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• 2012

At present the letter sizes of traffic sign are variously designated as 22 cm through 60 cm, however the basis for determination has not been found so far. Driver's visual acuity for getting a driver licence is required higher than 0.5. In order to interpret the information of traffic signs effectively, the minimum requirement of driver's visual acuity must be applied to determine the letter size of traffic sign. Therefore we reviewed that a driver with visual acuity of 0.5 could read the current letter sizes of traffic sign. In addition, a methodology was developed to determine the letter size of traffic sign satisfied with the driver's visual acuity of 0.5. This study established scenarios that were composed of visual acuity, reaction time, the number of lane and the letter sizes of traffic sign for each scenario were proposed. Current letter size of traffic sign would not be difficult for drivers with minimum visual acuity of 0.5 to recognize the contents or information of traffic signs. The method developed in this research has an advantage that can consider a human factor like driver's visual acuity for the design of traffic signs. There is also a meaning of making a basis for the letter size of traffic sign.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.2
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• pp.187-193
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• 2015

Purpose: This study was aimed to investigate effects of increased breath alcohol concentration (BrAC) which is the standard measurement of alcohol consumption in sobriety test under current laws on visual acuity and values of objective refraction. Methods: For twenty three males in 20s (average age $21.17{\pm}2.19$ years, body mass index (BMI) $22.09{\pm}2.16$) were selected. Distance and near visual test was performed at BrAC of 0%, 0.05% and 0.08%, and objective refraction with open-field auto-refractometer was also performed at different BrAC. Results: As breath alcohol concentration is increased, distance visual acuity was decreased, which was statistically significant, but near visual acuity was not changed. Also, values of objective refraction tended to be increased towards minus as breath alcohol concentration is increased. Conclusions: As breath alcohol concentration is increased, corrected visual acuity is decreased and refractive power is towards minus, it is necessary that visual acuity test and refraction measurement should be conducted under sober condition.

• Journal of Korean Ophthalmic Optics Society
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• v.7 no.1
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• pp.21-23
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• 2002

Compared visual acuity that is measured in a artificial myopia with the numerical calculation. Calculation included image's height as well as blur circle that is formed to retina. The blur circle calculated in geometrical optics model, and height of retinal image calculated by refractive power and visual acuity that is measured in a artificial myopia. Define this result as "blur ratio" about blur circle and height of retinal image, and investigated blur ratio relationship about visual acuity in a artificial myopia.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.2
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• pp.207-216
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• 2014

Purpose: In this study, we analyzed visual acuity of children according to the rearing of the type of parents. Methods: We have done a comparative analysis about before and after of corrected visual acuity according to the wearing actual conditions with the Korean National Health and Nutrition Examination Survey 2010 document. Results: Visual acuity before correction of twoparent family's children was 0.91, single parent family's children was 0.83, grandparents family's children was 0.77 in low income and twoparent family's children was 0.80, single parent family's children was 0.77, grandparents family's children was 0.50 in lower middle income. Conclusions: In the rearing of low-income children, the lack of attention to visual acuity management according to the type of parents leads to a failing of visual acuity in myopia. The role of the parents is very important during this time period, so it is necessary to provide social interest giving decline prevention of vision.