• Journal of Korean Ophthalmic Optics Society
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• v.20 no.4
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• pp.527-536
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• 2015

Purpose: In this paper, we have dealt with problems and improvement of korean optician system. Methods: Using the relevant material of korean optician system and international optometrist system, provides the theoretical basis of the need for regulatory changes optician. Results: The people with refractive errors are increasing, 67% of refractive error test is made from optical shop and korean optician are sufficient trained, many opticians are in charge of the refractive error test at the ophthalmic hospital. We have confirmed that current law does not reflect adequately the nature of optician's work. Conclusions: Since current capacity of the Korean opticians and education system ready to provide health services for people, therefore an korean optician must redefine the law to fit the reality.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.2
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• pp.59-62
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• 2008

Purpose: This study was designed to investigate the time-dependent changes of visual acuity after alcohol ingestion. Methods: Both the subjective and objective refraction, distant contrast sensitivity, and three needle tests were carried out at 1 and 3 hours after alcohol ingestion. Results: It was found that the degree of myoptization increased as the blood alcohol level increased in the range of average -0.25D ~ -0.35D when tested 1 and 3 hours after alcohol ingestion. Under the same test conditions the increase in blood alcohol resulted in the reduction in the function of dynamic stereopsis. However, the variation in contrast sensitivity was found to be insignificant for all spatial frequencies. Conclusions: The optician has to be well aware of the fact that alcohol could affect the visual acuity and functional tests, therefore inquiring of the alcohol ingestion prior to visual test can be necessary.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.26 no.2
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• pp.68-77
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• 2013

Objectives : This study reports a massive vision screening on preschool children of Yangsan city in Kyungnam Province. Methods : From March to July 2012, we conducted vision and color test on 1,409 preschool children aged from one to six and used Auto Kerato-Refractometer(KR-8900) on children with naked vision below 0.5 in order to detect the cause of poor vision. Written form of test result is filled and distributed to each parents. Uncooperative 195 children were excluded and the rest were statistically analyzed by using SPSS version 18.0 program. Results : 16 children(1.1%) had dyschromatopsia and the number of boys was threefold higher than that of girls. The average visual acuity was 0.8 to 0.9 regardless of age. 45 children(3.8%) showed myopia, 82 children showed hyperopia(6.8%), 4 children showed anisometropia(0.3%), among which 16 children were wearing glasses. Conclusions : This study has a great significance that a massive preschool vision screening was carried out by Korean medicine hospital for the first time.

• The Journal of Engineering Geology
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• v.31 no.3
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• pp.269-281
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• 2021

Land creeping is the imperceptibly slow, steady, downward movement o f slope-forming soil or rock. Because creep-related failures occur frequently on a large scale without notice, they can be hazardous to both property and human life. Korea Forest Service has operated the prevention and response system from land creeping which has been on the rise since 2018. We categorized and proposed three survey steps (e.g., preliminary, regional, detailed) for investigation of creeping susceptibility site with a focus on geophysical mapping of a selected test site, Yongheung-dong, Pohang, Korea. The combination of geophysical (dipole-dipole electrical resistivity tomography and reciprocal seismic refraction technique, well-logging), geotechnical studies (standard penetrating test, laboratory tests), field mapping (tension cracks, uplift, fault), and comprehensive interpretation of their results provided the reliable information of the subsurface structures including the failure surface. To further investigate the subsurface structure including the sliding zone, we performed high-resolution geophysical mapping in addition to the regional survey. High-resolution seismic velocity structures are employed for stability analysis because they provided more simplified layers of weathering rock, soft rock, and hard rock. Curved slip plane of the land creeping is effectively delineated with a shape of downslope sliding and upward pushing at the apex of high resistive bedrock in high-resolution electrical resistivity model with clay-mineral contents taken into account. Proposed survey steps and comprehensive interpretation schemes of the results from geological, geophysical, and geotechnical data should be effective for data sets collected in a similar environment to land-creeping susceptibility area.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.4
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• pp.555-560
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• 2013

Purpose: The aims of this study were to investigate the stereoacuity and subjective symptoms of aniseikonia with prescription of the size lens. Methods: Participants were myopic anisometropia patients with the binocular refraction difference between 1.75 D~3.50 D. Inclusion criteria of participants were no ocular pathology, no amblyopia, more than 1.0 of corrected visual acuity. With fully corrected spectacles and a correction with the size lens, Awaya aniseikonia test and Randot Stereo test were conducted respectively. In addition, subjective symptoms were also examined using questionnaire. Results: As the anisometropia increased, the aniseikonia increased. Under the anisometropia with same refractive correction was different for each individual. The prescription of size lens caused less aniseikonia than the general prescription of glasses. In addition, prescription of the size lens improved stereoacuity and relieved the symptoms of asthenopia. Conclusions: The prescription of size lens that can correct aniseikonia with prescription of glasses can improve stereoacuity and reduced asthenopia.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.2
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• pp.155-160
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• 2010

Purpose: The purpose of this study was to evaluate how phoria variations would vary with head positions, as well as to review the need to differentiate prism placement over either eye in a relation to the imbalance of the extraocular muscle. Methods: This study was carried out with 44 males (88 eyes) and 16 females (32 eyes) aged between 20 and 30. For all subjects, testings were performed using cover test, subjective refraction, phoria and vergence test. To analyze phoria variations comparatively for the head tilt test and the face turn test, phoria deviation were measured using the von Graefe. Results: For the phoria variation related with head tilt and face turn, a significant difference was observed in the group judged to be abnormal on the horizontal phoria of Morgan' norm (p<0.05); especially in patients who needed near prescription of Sheard's criterion, a higher variation was observed (p<0.05). The abnormal group was composed of patients who needed distance prescription of Sheard's criterion and ones who did not need the prescription, all of whom showed phoria variations, but the mean value was less than the near. Conclusions: With regard to the head tilt and face turn related phoria level, the patients who needed near horizontal prism prescription of Sheard's criterion showed a remarkably higher variation. Altogether, it is deemed to check whether extraocular muscles are ill-balanced in both eyes previously to determine the prism power on phoria level to the end that each of prism powers may be accurately determined.

• Journal of Korean Ophthalmic Optics Society
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• v.7 no.2
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• pp.41-45
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• 2002

To study the ametropia and the sort of glasses, especially progressive multifocal lens, for near purpose on Middle aged & Manhood. 500 adults were tested by the object and subject methods. Among the 500 adults, myopia is 22.4%, hyperopia is 61.4%, and emmetropia is 16.2%, respectively. In test of astigmatism, the amount of astigmatism for the age of forty one to under forty five with-the rule is 28%, the amount of astigmatism against-the rule is 43% and the amount of astigmatism with oblique is 11%, respectively. Whereas, the amount of astigmatism for the age of fifty six to under sixty with-the rule is 10%, the amount of astigmatism against-the rule is 71% and the amount of astigmatism with oblique is 19%, respectively. With-the-rule decreased with increasing age while against-the-rule increased with increasing age. The oblique astigmatism relationship to age could not be determined. The ratio of the progressive multifocal lens was 67.3% for male and 35% for female.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.31 no.2
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• pp.173-180
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• 2013

In this paper, we studied on measurement of soil deformation around the tip of model pile by close-range photogrammetry. The rigorous bundle adjustment method was utilized to monitor the soil deformation in the laboratory model pile-load test as function of incremental penetration of the pile. Control points were installed on the frame of the laboratory model box case and more than 150 target points were inserted inside the soil around the model pile and on the surface. Four overlapping images including three horizontal and one vertical image were acquired by a non-metric camera for each penetration step. The images were processed to automatically locate the control and target points in the images for the self-calibration and the bundle adjustment. During the bundle adjustment, the refraction index of the acrylic case of the laboratory model was accounted for accurate measurement. The experiment showed the proposed approach enabled the automated photogrammetric monitoring of soil deformation around the tip of model pile.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.3
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• pp.159-164
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• 2005

Accommodation and convergence is combination movement which is closely connected with each other. When one of them is stimulated, both of functions occur at the same time. Specially, the convergence by the accommodation's stimulation is called as accommodative convergence. That has excess or deficiency according to refraction state of eye. This study was performed by using both of Gradient method and Heterophoria method to 41 adults who have no any ophthalmic disease. 1. As the result of investigation about the distribution of heterophoria at distance, there were orthophoria of 5 subjects, exophoria of 32 and esophoria of 4. Exoporia occupied at the hightest rate. The distribution of heterophoria at near cover a wider range more than at distance. 2. When we measured the horizontal heterophoria amount in the state of relaxation of accommodation power of lens, exophoria amount increased in case of 38 subjects. 3. The person who has $4{\sim}6{\Delta}/D$ which conform to normal AC/A ratio occupied 27 subjects(66%) in Heterophoria method and 16(39%) in Gradient method, respectively.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.1
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• pp.93-104
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• 2004

In order to have a comfortable vision without any asthenopia in work place, it is very necessary to make a complete binocular correction in addition to the perfect correction of refractive deficits. For this, At first, the exact understanding of the required corrective value of the existing angular ametropia(associated phoria) is needed. The fact likely seems fact that a correction of refractive deficits could not to be reached with single optotype, the corrections of angular ametropia(associated phoria) with single optotype is impossible. The reason is that a most ametropia(associated phoria) is accompanied with the fixation disparity. To make a perfect measurement of ametropia(associated phoria), at least, 3 kinds of optotype is essential. This fact could be explained by stating the fusional stimulus in the binocular refraction tests on each eye. If these types of three tests have not practical practice. The most of many cases may result in undercorrection.