• Journal of Korean Ophthalmic Optics Society
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• v.18 no.2
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• pp.165-171
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• 2013

Purpose: This study are to analyze and to compare between pupillary size, reaction time, refractive error, corrected vision, dominant eye, static visual angle (SVA) and kinetic visual acuity (KVA) of male and female college students, to measure KVA of them in full correction and to identify changes of KVA by +0.50 D and -0.50 D spherical power addition respectively in full correction condition. Methods: KVA, SVA, pupillary size, reaction time, refractive error, corrected vision and dominant eye of 40 male and 40 female optical science students were measured by utilizing KOWA AS-4A, reaction time measurement program, subjective refractometer, and objective refractometer, and KVAs were measured when +0.50 D/-0.50 D were added in both eyes respectively. Results: Binocular KVA of whole subjects was $0.45{\pm}0.22$, and in monocular KVAs were $0.36{\pm}0.19$ for right eye and $0.34{\pm}0.19$ for left eye, and binocular KVA was significantly higher than monocular KVA. It appeared that the better SVA was, the better KVA was in significant way, and in terms of refractive error the less myopia amount was, the better KVA was, but it was not significant statistically. The lower astigmatism was, the slightly and significantly higher KVA was when dividing between equal or less than -1.00 D astigmatism group and over -1.00 D astigmatism group. In resulting from correction condition of refractive error KVAs were $0.45{\pm}0.22$ for full correction, $0.26{\pm}0.15$ for +0.50 D addition, $0.48{\pm}0.22$ for -0.50 D addition which indicates that KVA in over myopia correction was significantly the highest and followed by full correction and under correction. Similar findings were revealed in both male and female, and KVA of male was better than female in comparing between male and female. There was no significantly different KVA between dominant eye and non-dominant eye. Conclusions: Accordingly, it is concluded that KVA is related with far distance SVA, astigmatism amount, and refractive error amount except a dominant eye. Through this research, it was found that prescription for enhancing KVA is to make full correction or to overcorrect slightly myopia.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.1
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• pp.71-82
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• 2005

The aim of this study was to provide fundamental data for the factors influencing the asthenopia of emmetropia with phoria and alleviation of asthenopia. A total of 348 subjects, aged between 19 and 30 years old, who had no strabismus, an eye trouble or whole body disease, were examined using corrected visual acuity, corrected diopter, stereopsis and suppression tests from September of 2002 to September of 2004. We excluded 21 subjects for the following reasons: if they had an amblyopia affecting binocular vision or inaccurate data. After these exclusions, 327 subjects remained. We then individually measured the refractive error correction, pupillary distance, optical center distance, phoria, convergence, accommodation and the AC/A as well as the asthenopia during binocular vision using a questionnaire. After analysis of factors affecting asthenopia, we also examined the reductive effect of a prism on the asthenopia in subjects who had asthenopia. To determine the factors affecting asthenopia during binocular vision, statistic analyses were carried out using the Chi-square test and the multivariate Logistic regression model. The results of this study were as follow. For asthenopia during near binocular vision of emmetropia with phoria, in case of the lower the accommodation and convergence, a significantly higher rate of asthenopia was observed (p<0.001). When the AC/A is lower, the higher the rate of asthenopia was observed but not significantly and there was no association between phoria and asthenopia. When the multivariate logistic regression model was used to determine factors affecting binocular vision of emmetropia with phoria, in case of the lower accommodation and convergence, a significantly higher rate of asthenopia was observed. when the phoria is esophoria or higher exophoria, or when the AC/A is lower than normal, the higher the rate of asthenopia was observed but not significantly and there was no association between phoria. AC/A and asthenopia. Therefore accommodation and convergence could be predictive factors for asthenopia during near distance binocular vision. Prism was used among' subjects who had asthenopia during near distance binocular vision, the symptom of asthenopia was eased up to 74.2% in emmetropia with phoria.

• Journal of Korean Ophthalmic Optics Society
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• v.7 no.2
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• pp.149-154
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• 2002

This study is examined the difference between binocular spherical diopter and astigmatism diopter, spherical diopter, astigmatism diopter, and axis of astigmatism by sex and age with reference to the prescription of refraction for a total of 257 persons, 134 persons (male:78, female: 56)of teen-age and 123 persons of twenty-age who visit optical shop. Spherical correction diopter is mainly distributed to 280 eyes between -0.25D and -4.00D. And in astigmatism correction, for right astigmatism, 48 eyes(49.48%) are prescribed astigmatism diopter for a range of C-0.25~C-0.50D, 29 eyes(29.89%) has C-0.75~C-1.00D, 65 eyes(67.01%) has with the rule astigmatism. For left astigmatism, 43 eyes(42.57%) are prescribed astigmatism diopter of C-0.25~C-0.50D and 37 eyes(36.63%) has C-0.75C~1.00D, 73 eyes(72.27%) are shown with the rule astigmatism. And also each 108 persons(47.16%) and 28 persons(25.00%) are shown no difference between binocular spherical correction diopter and binocular astigmatism correction diopter, 94 eyes(39.49%) of teen-age and 104 eyes(42.27%) of twenty-age, male 119 eyes(41.90%) and female 79 eyes(34.34%) need correcting astigmatism. In pupillary distance, 165 persons mostly have 59~64mm.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.3
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• pp.201-206
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• 2010

Purpose: This study was to know the correlation among the dimensions of ocular components and refractive error on kindergarten children. Methods: The subjects were 80 preschool students who had no eye diseases. The refraction, corneal diopter, corneal radius, inter-pupillary distance, axial length, anterior chamber depth and dominant eye were measured and analysed. Results: It was shown that the highest correlation was between the axial length and the corneal diopter (r=-0.674, p=0.000). The ratio of height, weight and axial length (AL) to Corneal radius (CR) ratio were positively correlated with the axial length (r=0.351, r=0.408, r=0.488). The spherical equivalent of the refractive error and the corneal diopter were negatively correlated with the axial length (r=-0.302, r=-0.674). The anterior chamber depth and the corneal diopter were positively correlated with the AL/CR ratio (r=0.422, r=0.280). The spherical equivalent of the refractive error and the corneal radius were negatively correlated with the AL/CR ratio. Conclusions: It was shown that the AL/CR ratio was a very important indicator for diagnosing the refractive error of the preschoolers.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.1
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• pp.59-65
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• 2012

Purpose: The purpose of this study was to determine the distribution and correlation of accommodative lag with refractive error. Method: We had tested the clinical refraction and the accommodative lag in clinically normal 49 young adults (total 98 eyes) aged 18 to 25 years without abnormal binocular function. Monocular and binocular accommodative lag were tested with 0.50 D cross-cylinder lens and near vision test chart which had cross-hairs after full correction of LogMAR visual acuity over 0.05. Results: There was no statistical differences in monocular accommodative lag between right ($0.64{\pm}0.64$ D) and left eye ($0.63{\pm}0.64$)(p=0.858). The accommodative lag of male was higher than female and the range of the value was broader than female in binocular accommodative lag (p=0.015). The wider the inter-pupillary distance was, the higher the accommodative lag was (p=0.003). However, there were no differences with age (p=0.800) and dominant eye (p=0.402). The ranges of accommodative lag of low, middle, and high myopia were 0.75 ~ -0.25 D, 1.25 ~ -0.50 D, and 1.50 ~ -0.75 D, respectively, and the regression was 'y = -0.03953x+0.09205'. Conclusions: These data suggest that clinically normal young adults with high amounts of refractive error have more variable accommodative lag and increased spherical equivalent refraction.

• Journal of Korean Ophthalmic Optics Society
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• v.8 no.1
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• pp.29-33
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• 2003

There are reports that the myopia progression have been difference according to myopia degree and age. In this studies, we divided into three investigated groups. The A group is the lower elementary school(50), the B group is the high elementary school(50), the C group is the junior high school(50) and the D group is the high school students(50). The myopia progression have been compared with each group and most variable terms have been investigated. We have analyzed the refraction inspection record that were investigated to put on spectacles in three years(visiting three times or more). The subject of study were 200 persons(men 100, women 100), 1. The distribution of equivalence with ages : A group -2.72D, B group -2.90D, C group -3.53D, D group -3.96D. 2. The pupillary distance have been 57.4mm(A), 59.9mm(B), 61.6mm(C), 63.4mm(D). 3. On a monthly variation : -0.02D(A), -0.045(B), -0.050D(C), -0.025(D) in men, and -0.06D(A), -0.06D(B), -0.045(C), -0.04D(D) in women. 4. After due considering monthly variation and suppose that the variatting times of spectacles degress were time of refracting inspection. The result : 3.6 month for A group, 4.8 month for B group, 5.3 month for C group and 7.7 month for D group.

• Journal of Korean Ophthalmic Optics Society
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• v.7 no.1
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• pp.9-13
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• 2002

It is well known that the maximum amplitude of accommodation decreases with increasing age.(Presbyopia). With single vision lenses presbyopia can be corrected only for one viewing distance. With progressive power lenses presbyopia can be corrected for all viewing distances. But there are some other changes in the visual system with age which can not be corrected by spectacle lenses. Pupillary diameter decreases and the light transmission of the ocular media decreases. Therefore old people need more light, they need better illumination. Cone density in the retina decreases, this is only one example for changes in the sensory system. These changes in the visual system cause changes in visual functions. At the age of 80 visual acuity has decreased to half. Contrast sensitivity for gratings decreases mainly for high spatial frequencies very important is the increase of stray light in the ocular media and therefore the increase of glare. Veiling luminance increases by a multiple of approximately 4, Dark adaptation gets slower and light sensitivity is approximately 2 log units (factor 100) less when the eye is completely dark adapted. Also colour vision gets worse, especially at low luminances. Elderly people have problems with visual tasks which require divided attention between foveal and peripheral vision. An example is the measurement of the useful field of view. This useful field of view be expanded (improved) by visual training.