• Journal of Korean Ophthalmic Optics Society
• /
• v.1 no.1
• /
• pp.53-56
• /
• 1996

In testing visual acuity of kindergarten's children, single Landolt's ring in chart projector was used under proper intensity of illumination. According to the result of 218 eyes' test, 0.6 V.A. forms 8.5 % at the age of 3, 0.7 V.A. forms 84.7 % at the age of 4, and 1.0 V.A. forms 6.8 % at the age of 5. However, children's visual acuity has been gradually developed with their growth. None of emmetropia can be found through the test. All of the children have ametropic eyes.

• Journal of Korean Ophthalmic Optics Society
• /
• v.15 no.4
• /
• pp.307-312
• /
• 2010

Purpose: In this paper, we have dealt with problems of army supply system for eyeglasses and improvement plan. Methods: We collected the latest service request of MND (Ministry of National Defence) and case of U.S. Army and analyzed the data. Results: We treated contents, construction methods and plans for efficient use of vision DB (database) for Korean Army. We suggested several alternative proposal for eyeglasses supply system which made possible quicker delivery of eyeglasses to the soldiers and increase satisfaction. Conclusions: The Korean Army must construct vision DB to service high quality vision service to the solider. It is urgent that the Korean Army set up a unit to take charge of vision management and service. And the Korean Army need to upgrade supply system for eyeglasses.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.16 no.3
• /
• pp.129-135
• /
• 2016

There are many visual enhancement devices for people with low vision. However, almost conventional devices have been simple magnifying and high cost. The symptoms of people with low vision are very variety. It needs to control of image magnifying, brightness, and contrast to improve the visuality. We developed a portable microdisplay driver and device for visual enhancement. This device based on our suggested four methods such as image magnifying, specific color control, BLU brightness control, and visual axis control using a prism. The basic clinical experiments of the proposed Head Mounted Visual Enhancement Device (HMVED) have been performed. The results show beneficiary effects compared with conventional devices, and improve the life quality on people with low vision on account of low weight, low cost, and easy portability.

• Journal of Korean Ophthalmic Optics Society
• /
• v.5 no.2
• /
• pp.49-53
• /
• 2000

Comparing to an Image test chart which printed from computer. Hahn's standard test chart and Chart project test chart propose to make the program of an image test chart in computer. Test type of the test chart should be programed by difference size which was examined Hangul program of Hangul & Computer Co. An image test of visual acuity most decreased among 3 kinds of testing. Testing of Fixation disparity was same between Diplopia test and chart project test chart, so that. Design of test chart could be programed diverse by Hangul program of Hangul & Computer Co.

• Journal of Korean Ophthalmic Optics Society
• /
• v.21 no.2
• /
• pp.137-146
• /
• 2016

Purpose: The relationship between retinal conditions such as macular thickness and retinal volume of the eyes with central serous chorioretinopathy(CSC) and visual acuity was investigated. Methods: A total of 136 eyes from 78 subjects was divided into 5 groups: CSC eyes under treatment and its asymptomatic contralateral eyes, fully cured CSC eyes after the diagnosis and its contralateral, and normal eyes. Their uncorrected visual acuity(UCVA), best corrected visual acuity(BCVA), retinal thickness and retinal volume were further examined. Results: All of UCVA, BCVA, retinal thickness and retinal volume of CSC eyes under treatment were significantly different from those of asymptomatic contralateral eyes, fully cured CSC eyes and normal eyes. BCVA of the asymptomatic contralateral eyes was not significantly different from it of normal eyes, however, its retinal thickness and volume were significantly different from those of normal eyes. Increased degree of retinal volume along with the increase of retinal volume was greater in CSC eyes and its asymptomatic contralateral eyes, fully cured CSC eyes and its contralateral eyes than normal eyes. Conclusions: From the present study, it was revealed that the retinal thickness and volume of asymptomatic contralateral eyes of CSC increase as well as CSC eyes, and the change of BCVA due to CSC occurs only when the retinal thickness and volume increase in some extent.

• Journal of Broadcast Engineering
• /
• v.20 no.6
• /
• pp.901-911
• /
• 2015

Many studies tried to develop a 3D display based stereo test as a substitute for the conventional stereo test. Although many 3D monitor based stereo tests have various advantages over the conventional stereo tests with printed stimuli, they have a crucial limitation in manipulating disparity. The least value for disparity manipulation is one pixel, which is too big to screen the normal stereo acuity in pc environment with a short viewing distance. In this explorative study, a Gabor image was employed as a test stimulus, because its position can be manipulated by changing its phase information, which allows sub-pixel manipulation for disparity. Instead of employing the methods of the conventional stereo tests where measurement was made only once for each of a wide range of disparity values, 10 replications were administrated for each of 6 disparity levels. The results from the test using Gabor images were compared with those using random dot stimulus because the latter stimulus was exactly the same as that of the conventional stereo test. The correlation coefficient between two tests was found to be moderate. After one month later, the whole test was repeated in the same settings. The correlation coefficient between test and retest results from Gabor images was found to be as high as that from a random dot stimulus, implying high test-retest reliability. These results suggest that a Gabor stimulus could be used as a test stimulus for the valid and reliable stereo test, even in the limited condition, such as 3D environment with a short viewing distance and a condition for evaluating the stereo acuity very precisely.

• Journal of Korean Ophthalmic Optics Society
• /
• v.12 no.4
• /
• pp.95-99
• /
• 2007

This study performed apreliminary test with male high school students in Gwangju metropolitan city in order to determine visual function information of high school students. For the items in this preliminary test, there were inquiry, test for long distance unaided visual acuity, pinhole visual acuity test, colour vision test, cover test and stereo test. Most complaint related to eye was about blurred vision (28.4%) and over 90% of subjects had one or more, and among them, over 50% appealed two or more complaints. 76.1% of all subjects showed less than 0.7 in unaided distance visual acuity. In pinhole visual acuity test, 98% had an improved unaided pinhole visual acuity and most of them experienced an improvement and 2% had no change or dropped. The students with normal stereoscopic vision test were 85.6% and the students under normal range were 14.4%. In colour vision test, 7.9% of them were protanomaly and deuteranomaly and none of them had trichromasy and total color blindness. In cover test, it showed 30.2% of orthophoria, 8.2% of esophoria and 61.5% of exophoria, and none of them had strabismus.

• Journal of Korean Ophthalmic Optics Society
• /
• v.16 no.2
• /
• pp.167-170
• /
• 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
• /
• v.18 no.4
• /
• pp.549-554
• /
• 2013

Purpose: To determine the minimal illumination for visual acuity with the decimal vision chart and individual difference with varying contrast and illumination. Methods: Landolt's vision chart with 10 different grade of contrast was made. Minimal illumination was measured for 69 eyes using 100% contrast vision chart. Minimal contrast for identifying the chart was measured in conditions of the minimal illumination and 230 lx, respectively. Results: Minimal illumination was gradually increased with decrease of the chart size. Mean of minimal illumination to identify the 1.0 visual acuity was $74.39{\pm}25.90$ lx with range of 17~107 lx. In conditions of the minimal illumination and 230 lx, the minimal contrast for identifying the chart were gradually increased with decrease of the chart size in both conditions, the those deviation for 69 eyes was also increased. Conclusions: For refractive correction, examiners need to consider the individual difference for identifying the visual chart according to illumination and contrast.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.11
• /
• pp.3412-3417
• /
• 2009

The purpose of this study was to compare the quality of life in low vision to the one in normals. 20 multifactorial patients in low vision and 20 age-matched healthy normals took part in the survey and were orally estimated using NEI VFQ-25. The age of participants ranged 25 to 78. The mean score in low vision subjects was 55.88$\pm$14.76, whereas the one in normal subjects was 94.47$\pm$3.78. The age of low vision subject was highly correlated with the item Near Activities(r=-0.584), their LogMAR was fairly good correlated with the item Peripheral Vision(r=0.527). The quality of life in low vision is considerably depressed comparing to normals. Is there the nystagmus in low vision patient, it is inferred that the quality of life considerably leads to the problem.