• Journal of Korean Ophthalmic Optics Society
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• v.14 no.1
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• pp.109-114
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• 2009

Purpose: This study was designed to investigate the condition of refractive correction on wearing glasses currently of elementary school children and their accommodative ability in Jinju city. Methods: Objective refraction, subjective refraction, amplitude of accommodation, negative and positive accommodation, accommodative facility, and dynamic retinoscopy were examined on 60 elemenary school children who aged 8~12 wearing myopiacorrected glasses. Results: The condition of refractive corrections was distributed that a case of full correction was 11.7%, a case of low correction with more than 0.8 visual acuity (VA) was 10%, and a case of low correction with less than 0.8 VA was 78.3% in wearing glasses currently. In results from examination of accommodative ability, the number of children having accommodative anomaly is 8 persons (13.3%), they were divided into accommodation insufficiency (4 persons), accommodative facility insufficiency (2 persons), accommodation excess (1 person), and accommodation insufficiency related to ocular function (1 person). Conclusions: It is demanded a periodic inspection of refractive correction to growing children, and the refractive correction after due consideration to accommodative ability is really needed.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.2
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• pp.157-163
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• 2013

Purpose: This study was investigated weather watching 2D and 3D images effecting on accommodative function (AF), and differences between changes of AF by 2D and 3D. Methods: 50 subjects (male 30, female 20) aged 20's to 40's years old ($22.9{\pm}3.93$ years) who are available to watching 3D images were participated for this study. Accommodative amplitude (AA) by near point of accommodation (NPA), accommodative response (AR), positive and negative relative accommodation (PRA, NRA), accommodative facility (AF) were measured before, after watching 2D and 3D images at 1 m distance for 30 minutes respectively. Results: Accommodative amplitude after both watching 2D and 3D images decreased comparing to before watching images, and AA after watching 3D images was significantly lower than after watching 2D images. AR after both watching 2D and 3D images increased comparing to before watching images, but there was no difference between 2D and 3D. PRA and NRA were not significantly different between before, after watching 2D and 3D images. Accommodation speed by AF was increased for before watching ($13.52{\pm}3.32$ cpm) following by for after watching 2D images ($14.28{\pm}3.21$ cpm) and for watching 3D images ($14.90{\pm}3.27$ cpm). Conclusions: Watching images at close distance is effect to accommodation functions, and sequence of AA decrease of before watching images following by after watching 2D images and after watching 3D images may effect to asthenopia with same sequence as AA decrease. The results of increase of AF after watching images, specially 3D images show a possibility of vision therapy and further detail VT studies using 3D images are required in the future.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.2
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• pp.137-142
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• 2013

Purpose: This study was designed to investigate the current status of visual acuity for elementary school students in Muan-gun and to analyze improvements of their visual function after vision training for the elementary school students who have either insufficiency of accommodation or vergence. Methods: Subjective refraction, objective refraction and binocular function were examined for 335 elementary school children from year 1 to year 6 live in Muan area, and then 47 students who have symptoms of binocular dysfunction among them were selected. We analyzed and compared between before and after vision training (VT) in binocular vision function results. Results: The results show that most of the subjects had much problem in near point convergence (NPC) than accommodation. After the vision training, the average of subjects NPC was improved about 5.93 cm, from $11.57 {\pm}1.850$ cm for before VT to $5.66{\pm}0.965$ cm for after VT. After VT positive fusional vergence at near distance after VT was $19.64{\pm}3.66$ $\Delta$, which was as much as double of near phoria. Accommodative amplitude was improved from $10.02{\pm}2.566$ D for before VT to $12.30{\pm}1.397$ D for after VT, which similar to mean of expected accommodative amplitude of 11.27 years old. Conclusions: Among insufficiency of accommodation and vergence NPC was improved specially, and accommodative facility and other ocular functions were also improved. Therefore, it is considered the vision training is very effective to recover from visual function problems.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.1
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• pp.119-124
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• 2008

Purpose: To determine whether the accommodation of amplitude (AA) was changed by the color of the spectacle lens or object. Methods: AA was measured in forty subjects in their 20s when they viewed different targeton-background color combination with achromatic, gray, brown or green lens. Minus-lens procedures were used for the estimation of AA. Results: When subjects viewed the black-on-white, red-on-white and green-on-white targets, AA under tinted lens tended to be increased compared with AA under achromatic lens. Especially, the green lens significantly increased AA whatever the color of target was. Furthermore, as subjects viewed the green target, AA was the highest irrespective of the color of lens. AA was also changed depending on the color of background, so AA on the red background was lower than on the white background. On the contrary, AA on the green background was higher than on the red or white backgrounds. Of tinted lens, the gray lens increased AA the lowest, but the green lens did the highest. The number of subjects, whose AA were measured more than 9 D, reached to 12.5% with the gray lens, 21.3% with the brown lens, 22.5% with the green lens on the green background, but 5%, 6.5% and 6.5% on the red background, respectively. Conclusions: This results showed that AA varied depending on the color of spectacle lens, objects or background, and the eye fatigue could be decreased with proper color of spectacle lens accordingly.

• 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.15 no.3
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• pp.287-291
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• 2010

Purpose: The aim of this study was to compare binocular functions such as near point of convergence (NPC), AC/A ratios, heterophoria, accommodation, accommodation lag, positive relative accommodation (PRA), negative relative accommodation (NRA), positive relative convergence (PRC), negative relative convergence (NRC) in normal subjects and convergence insufficiency. Methods: 86 subject (male n=45, female n=41, mean $age{\pm}SD=23.27{\pm}2.85$ years) without amblyopia, strabismus, and ocular pathology were studied. Forty three patients each group were classified as normal subjects and convergence insufficiency group based on AC/A ratio and far and near phoria. Binocular function of the two groups was measured using phoropter. r. Results: The values between normal subjects and convergence insufficiency were 5.71 cm and 7.07 cm for NPC, 5.28 and 2.81 for Heterophria AC/A, 0.92 exo/3.36 exo and 2.17 exo/10.84 exo for far and near phoria, 15.49/23.30/13.30 and 13.50/20.02/9.09 for PRC, respectively. However, there were no significant differences between normal subjects and convergence insufficiency for accommodative amplitude, accommodative lag, PRA, NRA, BI vergence test, BO vergence test, NRC. Conclusions: Both groups were a significant difference for cover test, NPC, Heterophria AC/A, far and near phoria, break point of PRC, and recovery point of PRC.

• Journal of information and communication convergence engineering
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• v.14 no.3
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• pp.191-199
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• 2016

In this study, we investigate the safety requirements and test methods of a radiofrequency stimulator. The main test items include controls of a minimum output, accommodation range, and output parameters that have been known as the safety requirements in conformity with international standards. As the test criteria for controlling the minimum output, an increase or decrease in a unit of 1 mA or 1 V or less was applied to the output amplitude regulator for both continuous and discontinuous control, and the output at the minimum setting was manipulated to not exceed 2% of the maximum setting. For controlling the output parameters, one of the representative test criteria states that the current limit of 250 mA should be equal to or less than 1,500 Hz. Consequently, when applying the radiofrequency stimulator on the human body, we need to ensure that the safety requirements conform to the international standards.

• Journal of Korean Ophthalmic Optics Society
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• v.7 no.2
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• pp.33-39
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• 2002

The purpose of this study is to evaluate the effects of continuing work on VDT(video display terminal). Therefore, we examined visual fatigue by a questionnaire and measured frequency of blinking, tear film break-up time(BUT), height of palpebral fissure, visual acuity, refraction with retinoscopy and accommodation before and after two hour long VDT work. For the ocular symptoms, the greatest number was tired eyes accounting for 34%. In the visual symptoms, blurred vision was the highest rate of 83% and in case of systemic symptoms, shoulder pain was 38% marked top ranking but other symptoms were also distributed similar rate. The frequency of blinking during VDT work decreased significantly comparing with the one at rest. The average frequency of blinking is 8/min during VDT work and 22/min at rest. The BUT measured immediately after VDT work decreased much more than in the resting state. The average BUT was 7sec immediately after VDT work and 12sec at rest. The height of palpebral fissure during VDT work increased significantly comparing with the value at rest. The average height of palpebral fissure was 7.69mm at rest and 9.04mm during VDT work. The average visual acuity decreased almost 9.5% from 0.63 to 0.57, but refraction with retinoscopy increased about 0.28D to the direction of myopic shift. The amplitude of accommodation decreased approximately 1.49D from 7.98D to 6.49D and this resulted from the prolongation of near point of accommodation. Near point of convergence also was prolongated from 9.45cm to 10.30cm after VDT work.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.3
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• pp.400-409
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• 2000

This study used in vivo intracellular and extracellular field potential recording to evaluate the intrinsic membrane properties and connection pattern within facial nucleus. 1. There were four subdivisions of medial, intermediate, lateral, and dorsolateral in facial nucleus. 2. Principal cells in the facial nucleus was recorded from and filled with neurobiotin in anesthetized rats. The extent of their dendrites and the characteristics of cell body were examined. 3. Principal cells had a large amplitude action potential and afterhyperpolarization was followed a single action potential. 4. The response from facial motonucleus to electrical stimulation of the facial nerve was mainly a monophasic wave, with a latency of 1 msec, which was assumed to reflect antidromic activation of facial motoneurons. In some of rats the response in addition showed late components at a latency of about 7-8 msec, but its amplitude was small. 5 Most of cells exhibited accommodation of spike discharge upon depolarization of membrane by 0.8 nA for 400 ms. Our results support the hypothesis that there normally are weak connections between different parts of the facial motonucleus to explain pathophysiology of hemifacial spasm and facial naive paralysis.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.3
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• pp.305-309
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• 2012

Purpose:This study was conducted to research any effect on aided distance visual acuity and refractive error changes by using smartphone at near for long term. Methods: 20($20.6{\pm}0.9$ years) young adults subjects with no ocular diseases, over 0.8 of aided distance visual acuity, normal amplitude of accommodation and normal accommodative facility agreed to participate in this study. The subjects were divided into two group, Group 1 (15 cm fixation distance) included 10 subjects and Group 2(40 cm fixation distance) included 10 subjects. Aided distance visual acuity and refractive error were measured before and after using smartphone for 30 minutes by auto-chart project (CP-1000, Dongyang, Korea), phoropter (VT-20, Dongyang, Korea), auto refractor-keratometer (MRK-3100, Huvitz, Korea). After then, the subjects looked at distance with wearing spectacles. Refractive error was measured at 5 minutes, 10 minutes, and 15 minutes later, respectively. Results: After using smartphone at 15 cm for 30 minutes, there was statistically significant reduction of aided distance visual acuity (p=0.030) and increasing myopia (p=0.001). The increased myopia was not statistically significant after 5 minutes rest (p${\geq}$0.464). However there was no statistically significant changes in aided distance visual acuity (p=0.163) and refractive error (p=0.077) after using smartphone at 40 cm for 30 minutes. Conclusions: It is recommend to keep 40 cm off the smartphone from eyes to avoid any aided distance visual acuity and refractive error changes. If smartphone is used closer than 40 cm, a rest for 5 minutes is also recommend after every 30 minutes use with smartphone to avoid any aided distance visual acuity and refractive error changes.