• Journal of Korean Ophthalmic Optics Society
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• v.10 no.2
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• pp.111-118
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• 2005

The optotypes widely used as a necessity in the course of optometry are the world authorized versions which contain items such as the Landolt's rings, Snellen's chart and also Arabian numbers, Korean letters, Pictures and so on. In Korea, the Hahn-chun-suk test chart has been In use generally alolng with Chung-san test chart and Jin-yong-han test chart also in use on the wall. But these sort of test charts hung on the wall have some problems such as the difference in test results owing to the rate of illumination and so a more accurate method is required. To solve the problem of inaccuracy in optometry, the projected type of charts with digital instrument such as the beam projector has been developed lately. This chart projector with consistent high resolution and the ability to provide various charts can help eye examiner perform effective examination and thus is looked positively upon as the automated total optometry system. So in this study our purpose is to examine the accuracy of the projected chart. It was done by comparing it with the frequently used test chart. The results of experiment are as follow. When the projected chart was used, cases that subject read charts one step higher were 10%, two step higher 2% than perfectly corrected vision. When Han-chun-suk test chart was used, cases that subject read charts one step higher were 12%, and two step higher were 4%.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.3
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• pp.277-284
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• 2015

Purpose: The study aimed to evaluate the effect of circle contact lens wearing on visual quality of the eyes after a refractive surgery. Methods: The objective visual quality was evaluated for 40 eyes who did not get refractive surgery and 30 eyes who got a refractive surgery after applying plano circle contact lenses on their eyes, respectively. Modulation transfer function (MTF), objective scatter index (OSI) and the focusing ratio on retina (Strehl ratio) were measured by using optical quality analysis system (OQAS) and the correlation between pupil size and objective visual quality was analyzed by measuring the pupil size. Results: When wearing circle contact lens on the eyes after refractive surgery, MTF and Strehl ratio were reduced and OSI was increased compared with the eyes without refractive surgery. The eyes after a refractive surgery showed more significant difference changes in MTF, OSI and Strehl ratio according to the pupil size compared with those without refractive surgery. Conclusions: The results showed that wearing of circle contact lens after the refractive surgery has deteriorated the objective visual quality based on the quality of focused image on the retina. Therefore, we suggest that sufficient understanding and consideration about the deterioration of visual quality is necessary in the case of circle contact lens wearing after refractive surgery.

• Journal of Korean Ophthalmic Optics Society
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• v.21 no.1
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• pp.77-81
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• 2016

Purpose: This study was performed to investigate the difference of meridional visual acuity and the loss of corrected visual acuity (VA) in order to emphasis the importance of astigmatic correction. Methods: 64 subjects (122 eyes) aged $22.75{\pm}2.36years$ participated in this study. After full correction of astigmatic refractive error, VA was measured in which the direction of the slit filter was matched with astigmatic axis and $90^{\circ}$ to the astigmatic axis. Results: 52 eyes showed no difference in VA between the two direction. However 70 eyes had difference VA between them. 14 out of 52 eyes and 24 out of 70 eyes had under 1.0 in monocular VA. The astigmatic degree was higher in the existence of VA difference between the two direction than non-existence. The difference is higher with under 1.0 monocular VA. Monocular VA is closely related to the focal line having better VA in the principal focal line. Glasses replacement period was analyzed as 6~12 months for the preservation of better VA. Conclusions: The final glasses prescription has to be given with full correction because continued under-correction for astigmatism causes meridional VA difference.

• The Journal of the Korea Contents Association
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• v.16 no.12
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• pp.132-142
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• 2016

The study aimed to examine the state of visual acuity tests in preschoolers and determine the factors affecting the deterioration of their vision. A total of 172 pair, child aged 5-7 years and either one of their parents, were recruited from childcare centers or kindergarten between August 2015 and January 2016. Questionnaires were administered to the parents, and the children's visual acuities were measured. Using forward selection in logistics regression analysis, factors affecting vision deterioration were elucidated. Of 172 children, 128 (74.4%) had undergone a visual acuity test previously and 77 (44.8%) showed a deterioration in their vision. Children who had undergone their first visual acuity test after the age of 7 years (OR=7.425, CI=2.844- 19.385) and showed more abnormal eye symptoms, such as squinting or tilting the head to see or falling down frequently (OR=3.084, CI=1.202-7.914) and whose age was younger (OR=10.335, CI=3.252-32.848), were more likely to develop deterioration of vision. Children who had a posture such that they looked up at the computer monitor from below (OR=.075, CI=.022-.255), were less likely to show deterioration of vision. It can be inferred that early visual acuity tests is essential to detect deteriorated vision of preschoolers. Therefore, it is necessary to educate parents, personnels in day care center, and health clinics about the importance of early visual acuity tests and close observation of specific behaviors related to vision deterioration. Development of precautionary intervention program of vision deterioration in preschoolers and examination of its effects are needed.

• 한국정보교육학회:학술대회논문집
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• 2004.08a
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• pp.457-465
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• 2004

한국정보문화진흥원에 따르면 국내 전체 가구 컴퓨터 보급률은 매년 증가하고 있는 추세이며 전체 국민의 인터넷 이용률 및 계층별 인터넷 이용률 모두 매년 증가하고 있어 사회 전반의 정보화가 크게 진전되고 있다. 이로 인한 어린이들의 컴퓨터 사용도 급격하게 늘어나고 있어 이제는 컴퓨터 사용에 따른 시력장애는 단지 어른들에만 해당되는 것은 아니다. 버컬리 대학의 P.Hoenig이 수행한 한 연구는 컴퓨터로 많은 시간을 보내는 어린이와 근시에는 밀접한 상관관계가 있다는 것을 보여주고 있다. 컴퓨터를 사용하는 성인 70% 이상이 컴퓨터 시력 증상(CVS)을 겪고 있으며 이 증상은 걷기 전부터 컴퓨터를 접해온 많은 어린이들에게도 나타날 수 있다는 사실이 밝혀졌다. [1] 한편 컴퓨터가 직접적으로 아이 시력을 떨어뜨리지 는 않으며 어린이들이 컴퓨터를 어떻게 사용하는가에 따라서 시력에 영향을 미친다는 연구결과도 있다. 본 연구는 컴퓨터의 사용시의 여러 요인이 초등학교 고학년 어린이들의 시력에 어떠한 영향을 미치는가를 다각적인 설문조사를 통해 상관관계를 분석한 결과 어린이들의 컴퓨터 사용시간의 증가는 VDT 증후군의 증가와 시력저하로 이어지고 있고, 학부모들의 어린이들의 컴퓨터 사용 대한 무관심도 시력저하의 요인이 되는 것으로 밝혀졌다. 이에 따라 어린이들의 컴퓨터 사용시의 시력보호 방안도 제시하였다.

• Journal of Korean Ophthalmic Optics Society
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• v.21 no.1
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• pp.61-68
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• 2016

Purpose: This study investigated differences in stereoscopic fusional area between those with good and poor stereo acuity in viewing stereoscopic displays. Methods: Stereo acuity of 39 participants (18 males and 21 females, $23.6{\pm}3.15years$) was measured with the random dot stereo butterfly method. Participants with stereo-blindness were not included. Stereoscopic fusional area was measured using stereoscopic stimulus by varying the amount of horizontal disparity in a stereoscopic 3D TV. Participants were divided into two groups of good and poor stereo acuity. Criterion for good stereo acuity was determined as less than 60 arc seconds. Measurements arising from the participants were statistically analyzed. Results: 26 participants were measured to have good stereo acuity and 13 participants poor stereo acuity. In case of the stereoscopic stimulus farther than the fixation point, threshold of horizontal disparity for those with poor stereo acuity were measured to be smaller than the threshold for those with good stereo acuity, with a statistically significant difference. On the other hand, there was no statistically significant difference between the two groups, in case of the stereoscopic stimulus nearer to the fixation point. Conclusions: In viewing stereoscopic displays, the boundary of stereoscopic fusional area for the poor stereo acuity group was smaller than the boundary of good stereo acuity group only for the range behind the display. Hence, in viewing stereoscopic displays, participants with poor stereo acuity would have more difficulty perceiving the fused image at farther distances compared to participants with good stereo acuity.

• 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.12 no.3
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• pp.117-120
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• 2007

The actual condition of periodic visual acuity testing for 304 undergraduate students were investigated for the purpose of prepared some fundamental data on the development of the eye-health education program and conducting a practical application. Many undergraduate students (59.21%) had not been tested periodic visual acuity testing. The ratio of periodic visual acuity testing for female was higher than male. There was statistical significant difference dependence on the native place, the educational system, and the division of major. The ratio of periodic visual acuity testing for undergraduate students from city was 43.07%, from rural area was 24.32% (p<0.05). According to the educational system, the ratio of periodic visual acuity testing of university students was 65.71%, college students was 27.64% (p<0.001). The ratio of periodic visual acuity testing of undergraduate students who have corrected their visual acuity was 50.25%, while that of students who have not corrected was 23.36% (p<0.001).

• The Korean Journal of Vision Science
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• v.20 no.4
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• pp.523-530
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• 2018

Purpose : The purpose of this study was to investigate the difference in the dynamic visual acuity between (DVA) the distance and near and the effect of change of accommodative stimulus on the dynamic visual acuity by the addition of the plus lens. Methods : The study involved 40 male and female adults ($22.84{\pm}2.43$ years old) with over 1.0 of visual acuity and without systemic disease or ocular disease. We compared the distance and near DVA and the change of DVA induced by the addition of the plus lens(+0.50D, +1.00D, +1.50D). Results : The distance DVA and near DVA are $78.86{\pm}19.46deg/sec$ and $76.90{\pm}18.05deg/sec$ respectively. The distance DVA was slightly higher(p=0.04). The higher the distance DVA, the higher the positive correlation with the near DVA and distance DVA, and distance DVA was higher in those who had higher the near DVA(r=0.95, p=0.00, Fig. 4). The near DVA according to the change of accommodative stimulus was $75.95{\pm}18.85deg/sec$ in full correction and the near DVA with +0.50D spherical power was $76.95{\pm}16.45$ but there was no statistically significant differences(p>0.05). However, the near DVA with +1.00D spherical power was $79.02{\pm}13.51deg/sec$ and it was slightly higher. Also, the near DVA with +1.50D spherical power was $84.28{\pm}18.96deg/sec$, there and it was statistically significant difference(p<0.05). Conclusion : There is no difference between distance and near DVA, but near DVA is also excellent if distance DVA is good. The DVA increases as added a plus lens for controlled accommodative stimulation changes.

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.2
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• pp.99-104
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• 2001

This study surveyed common sense of testing eye vision, feeling of own vision and wearing glasses, and method of wearing glasses using questionnaire for 625 primary student(male 322, female 303) live in Iksan city, Jeon buk Province. The question about the selection of testing vision office answered ophthalmic optics only 12.6% by common sense but 38.8% among testing vision students had been checked the visual acuity in ophthalmic optics. 40% student of all answerer have a poor vision by self-evaluation testing and realized when they look far vision is 46.4% among the poor vision answerer, look black board is 26.0%, look monitor is 18.4%, and reading is 9.9%. 46% answerer of the subjective poor vision who tested eye vision by self-evaluation did not correct eye vision. 48.7% answerer among uncorrect eye vision is because of having no chance to test. The question of effect in wearing glasses answered that the 48% of a1l answerer will be worse the visual acuity, the other is getting better and unchanged eye vision by common sense. The question about how looks like glasses wearer answered that the 45.8% answerer is uncomfortable appearance by common sense. 32.3% answerer of the glasses wearer became a failure wearer because glasses was uncomfortable to fit primary student.