• Journal of Korean Ophthalmic Optics Society
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• v.5 no.2
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• pp.99-105
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• 2000

The classifying distribution by the action style was opticion 100, photoartist 100, college student 100 for the simple myopic 35%, for the simple myopic astigmatism 2%, for the compound myopic astigmatism 30.6% for the mixed astigmatism 62.6% for the compound hyperopic astigmatism 37.4% for the ratio of emmetropia 22.4% respectively. The retractive erroreye were -0.50~-2.00Dptr for the simple myopia 14%, -2.00~-6.00Dptr 16%, -6.00Dptr 5%, C-0.25(90.180)~C-2.00DptrAxis(90, 180) 2% for the simple myopicastigmatismS-0.25C-0.25DptrAxis(90, 180)~S-1.00C-1.00DptrAxis (90, 180) 22.6%, S-1.00C-1.00 DptrAxis (90, 180)~S-2.00C-2.00DptrAxis(90, 180) 8% for the compound myopic astigmatism. S+0.25C -0.25DptrAxis(90, 180)~S+2.00C-2.00DptrAxis(90,180) 6.2% for the mixed astigmatism. S+0.25C+0.25DptrAxis(90,180)~S+1.00C+1.00DptrAxis(90,180) 3.4%, S+1.00C+1.00DptrAxis(90,180)~S+2.00C+2.00DptrAxis(90,180) 0.34% for the compound hyperopic astigmatism.

• Journal of Korean Ophthalmic Optics Society
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• v.3 no.1
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• pp.103-113
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• 1998

Until now, the study of eye refractive error examination for high school students are a few report that in Korea. In particular, there is few report about the visual power for same group during several years. We compared the study of refractive error done this year with that reported three years ago at the same high school. From the these data, the distribution of ammetropia was investigated. The study of refractive error for high school students was also compared with those reported before for the Adults and the middle school student. When the visual power is refered to spherical equivalent, the 36% of the whole students examined above had emmetropia and the other part of them fumed out to be ammetropia which is classify to 60.6% belonged to myopia and 4.4% belonged to hyperpia. The ratio of myopia for this year students is increased in comparision with the students in 1995. The ratio of emmetropia for this year students is 7.4% higher, and the ratio of myopia for this year students is 4% higher, but the ratio of hyperopia is very lower than that for the adults in 1997. In the kind of refractive error, it is classified that a simple myopia is shown to highest ratio as a 28.6% of 1212 eyes examined, a compound myopic astigmatism to the next high ratio as a 22.4%, a simple myopic astigmatism as 14.4%, a simple hyperopic astigmatism as 3.1%, a mixed astigmatism as a 1.7%, a simple astigmatism as 1.2%, a compound hyperopic astigmatism as 1.2%, respectively. The percentage of an astigmatism is a 76.7% of total eyes examined if Cyl-0.25 Dptr is included to an astigmatism. On the other hand, The percentage of an astigmatism is a 45.6% of total eyes examined if Cyl-0.25 Dptr is excluded to an astigmatism. In the kind of astigmatism, the number of students had an astigmatism with the rule is about 4.5 times than that of astigmatism against the rule. From the result of comparision the right eye with the left eye, the right eye of the students had more a myopic refractive error than the left eye, which is same as adults' case, there is no difference in a refractive error between the boy students and the girl students.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.1
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• pp.113-117
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• 2008

Purpose: This study is to survey that uncomfortable feeling of visual acuity in the first wearing glasses, the number of visiting in age, above vision ranging and refractive errors, astigmatism, and anisometropia. Methods: Automatic refraction and naked visual acuity test executed to receive prescription glasses that the man 509 and women's 499 people visited for the first time, among 3~15 years old who visited an ophthalmoiogical hospital, from January to December, 2003. Results: The first wearing glasses started 3 years old and the most cases was 8~9 years old when they were visited visual acuity 0.5 to 0.7 in most cases. Refractive errors appeared 8 years old and its most plentifully with 20.4%, 92.2% was myopia and 5.2% was hyperopia for the man. Also cases of women was 91.9% for myopia and 5.1% for the hyperopia. Spherical equivalent power was S-1.50${\pm}$1.10D and appeared 62.3% for the low myopia. Astigmatism was appeared 44.6% for the with the rule astigmatism and 75% was cylinder power lower than 1.00D. Cases of simple astigmatism need to glass when was cylinder power C-1.37${\pm}$1.01D, and C-0.50D appeared most distribution. More than 2.00D anisometropia appeared 2.3% for the whole subjective. Conclusions: Of the first wearing glasses visual acuity is 0.5~0.7, spherical equivalent power is S-1.50${\pm}$1.10D, cylinder power of simple astigmatism is C-1.37${\pm}$1.01D.

• Journal of Digital Convergence
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• v.12 no.12
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• pp.485-490
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• 2014

The purpose of this Study investigated corneal power, corneal astigmatism and corneal axis according to spherical equivalent of refractive error. We measured spherical equivalent, corneal power and corneal astigmatism in 100 subjects from January 2014 to July 2014. Measured spherical equivalent of refractive error were $-3.01{\pm}3.79D$, corneal power of $43.79{\pm}1.60D$ and corneal astigmatism of $-1.17{\pm}0.79D$ respectively. Prevalence of spherical equivalent of refractive error were as follows : myopes (61%), emmetropes (22%), hyperopes(17%). Corneal astigmatism of refractive error greater than +0.75D was 63% and prevalence of corneal astigmatism were as follows : with-the-rlue astigmatism (84.13%), against-the-rule astigmatism(9.52%) respectively. Corneal power by spherical equivalent increased from hyperopia to myopia. Between spherical equivalent of refractive error and the mean corneal power was significant correlation(r=-0.25, p=0.01). A correlation were found between corneal power and spherical equivalent of refractive error in adults. They have the highest distribution of prevalence myopia among the refractive error. When the refractive error was increased, we found that corneal power was steeper. It is recognized that this can be refractive error factor and correct visual function is considered.

• Journal of Korean Ophthalmic Optics Society
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• v.11 no.3
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• pp.187-192
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• 2006

The purpose of this research was to measurement real accmmnodative response amount of emmetropia using both eyes open-view auto-refractometer. We classified 377(male 146, female 231)eyes showing good naked vision at least 1.0, with a spherical equivalent refraction of under ${\pm}0.50D$ and cylindercal refraction of under -0.75D, from 10 to 59(mean $25.8{\pm}12.4$) years into 5 groups with 10 year interval and analyzed change of the near astigmatism and accommodative response amount to distinction of age. Age comparison, total mean 1.47D, 10 years age group 1.63D, 20 years age group 1.57D, 30 years age group 1.71D, 40 years age group 0.97D, and 50 years age group 0.05D. It was no difference between 10 to 30 years age group, But it showed the decre8.se which is remarkable from above 40 years age group and it does not almost response from above 50 years age group. Sexual difference, the man appeared some highly in male(mean $26.4{\pm}12.3$ years) 1.56D m female(mean $26.4{\pm}12.3$) 1.43D. Near-astigmatism power change, mean +0.12D, 10 years age group +0.06D, 20 years age group +0.16D, 30 years age group +0.09D, 40 years age group +0.05D, and 50 years age group +0,06D. No significant difference of astigmatism powers among the an groups, but from all years age group the astigmatism power appeared more highly far-astigmatism than near-astigmatism. Near-astigmatism axis change in the far-astigmatism changes at under ${\pm}10^{\circ}$ 103 eyes, above ${\pm}10^{\circ}$ rotation clockwise direction 108 eyes, above ${\pm}10^{\circ}$ rotation counter-clockwise direction 101 eyes. It was analyzed near-astigmatism axis change.

• Journal of Korean Ophthalmic Optics Society
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• v.4 no.2
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• pp.135-140
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• 1999

To investigate the visual acuity of the women middle and high school students, the visual acuity test was performed the object and subject methods. The results were as follows; 1. The eye types were 96.7% positive for myopia, 2.5% for emmetropia, and 0.8% for hyperopia, respectively. 2. The abnormal refraction eyes were 61% positive for simple myopia, 35.2% for myopitic compound astigmatism, 3% for myopic simple astigmatism, and 0.8% for simple presbyopia, respectively. 3. The asix of astigmatism were 95% positive for irregular astigmatism axis, 3% for regular astigmatism axis, and 2% for oblique astigmatism axis, respectively. 4. On the total myopic spheric power, the -0.50

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.1
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• pp.77-81
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• 2008

Purpose: This study was to investigate the refractive state of an asian population (male: 39, female: 53) from 21 to 30 years old who visited the A optical shop at jongnogu in seoul. Methods: The visual acuity test was performed by the object and subject method. Results: Among the 184 eyes, myopia is 83.16% and emmetropia is 16.84%, respectively. As for the equivalent spheric power of myopic abnormal refractive eyes, the -m0.5Dt < spheric equivalent ${\leq}$ -2.00Dt was 40.53%, the -2.00Dt < spheric equivalent ${\leq}$ -6.00Dt was 51.63% and anything over the -6.00Dt was 7.85%. The percentages of with-the-rule, against-the-rule and oblique astigmatism among people with astigmatism were 46.67%, 35.56% and 7.77%, respectively. The average of pupillary distance in male (64.5${\pm}$2.9 mm) was greater than that in female (61.9${\pm}$2.3 mm). Conclusions: Korean opticians were provided some useful information about making up a prescription by this research.

• Journal of Korean Ophthalmic Optics Society
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• v.2 no.1
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• pp.133-143
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• 1997

A population-based study of people aged above 20 years showed that 32% had emmetropia and 68% had ammetropia(myopia 56.6%. hyperopia 11.4%) city in Korea. The percentage of ammetropia in population based study is higher than that of clinic(O.P.D.) based. A 83.3% of the ammetropia had myopia. which is higher than 76.3% of 1968 and 76.9% of 1975 years. A 16.7% of the ammetropia had hyperopia. which is lower than 19.4% of 1968 and 17.3% of 1975 years. In the kind of refractive error. 32.1% of 985 eyes examined had compound myopic astigmatism. 18.2% had simple myopic astigmatism. 14.2% had simple myopia. 6.8% had simple hyperopic astigmatism, 5.0% had mixed astigmatism, 4.7% had compound hyperopic astigmatism and 3.6% had simple hyperopia. In the difference of binocular refractive error, 29% had 0.50~2.00 Dptr difference and 3.6% had difference above 2.00 Dptr. In age related myopic refractive error, 76.7% of people aged 20~29 years and 74.0% of 30~39 years had myopia. It is due to overstudy for entrance into a university that the percentage of myopia is higher than that of abroad. In age related hyperopic refractive error, 2.9% of people aged 20~29 years, 0.6% of 30~39 years. 6.3% of 40~49 years, 16.0% of 50~59 years and 63.9% of 60~69 years had hyperopia. It shows that the age related hyperopic refractive error was significantly increased at aged 40~49 years. The right eye had more myopic refractive error than left eye.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.2
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• pp.199-206
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• 2014

Purpose: The present study was aimed to investigate the correlation between higher-order aberration and myopic degree by the analysis of fluctuation of high-order aberration according to the change of myopic degree in certain ranges of myopia and astigmatism. Methods: The high-order aberration in a total of 992 eyes was analyzed by using a LADARWave device employing Hartmann-Shack system, and the relation between high-order aberration and myopia by the change of myopic degree through manifest refraction test. Results: In all subjects, spherical aberration and total coma aberration were significantly increased by the increase of myopic degree, however, trefoil aberration and astigmatic aberration and tetrafoil aberration were decreased. With the group of lower myopic degree, the change of coma aberration was greater by myopic degree and its change was significantly different. The change of spherical aberration by myopic degree was greatly large in the a group of -3.00 D or more and the group of -6.00 D or more where as its change was not large in the group of lower than -3.00 D. The significant decrease of coma aberration was observed only in the group of astigmatic degree of -1.00 D or less when analyzing the correlation between the higher-order aberrations and myopia in the certain groups of astigmatic degree. In the case of spherical aberration, the significant change was shown in all astigmatic groups, however, its increase was larger with the increase of myopic degree in lower degree of astigmatism. The consistent relationship in variations of horizontal and vertical coma aberration in certain myopic and astigmatic groups was neither established nor statistically significant. Conclusions: It is concluded that the correlation between the higher-order aberration and low-order aberration obtained from the results of the present study can help the understanding related to vision quality and the improvement of vision quality.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.3
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• pp.305-313
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• 2014

Purpose: A correlation between the rotating direction and rotation amount according to the eccentricity was analyzed in the present study when fitting the toric soft contact lens. Methods: One hundred fourteen eyes of with-the-rule astigmatism in 20s and 30s were appropriately applied toric soft contact lens by the guideline of manufacturer and fitting evaluations and analyzed the rotating direction and rotation amount when fixating at primary position and 8 different directions of gaze. The speed of reorientation and the correlation between the rotation amount and cornea eccentricity were also analyzed when rotating $45^{\circ}$ each toward the temporal and nasal direction. Results: The cornea eccentricity and rotation amount was shown positive correlation. For the gaze of direction, it was identified that the gaze of directions other than the gaze of direction towards the nasal and temporal had correlation, and among them, the gaze of directions to superior and the superior-temporal showed the tendency of decreasing rotation amount as the cornea eccentricity increased. On the contrary, the gaze of direction towards the inferior, inferior-temporal, superior-nasal, and inferior-nasal showed tendency of increasing rotation amount as the cornea eccentricity increased thus, it was identified that the cornea eccentricity showed different correlation according to the gaze of direction. For the case of re-orientational speed, the speed of lens reorientation in the group having the smallest corneal eccentricity was fastest in both direction but was not significantly different. Conclusions: Considering cornea eccentricity to current method of prescribing toric soft contact lens which is based on total astigmatism, it will be helpful to establish the optimal axis stabilization.