• Journal of Korean Ophthalmic Optics Society
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• v.5 no.1
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• pp.159-163
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• 2000

In this study, It obtained that how myopitic astigmatism eyes appear in highschool students. The results were as follows. 1. In test, myopitic astigmatism eyes of men students are measured 60% in ratio and women students are measured are 57% in ratio. 2. In $-1.00{\geq}$cyl>0.00 Dptr, myopitic astigmatism eyes are measured 82% in ratio and in $-1.50{\geq}$cyl>-1.00 that is measured 12% in ratio. 3. In -2.00>cyl, myopitic astigmatism eyes are measured 6% in ratio. 4. In the kind of astigmatism, The direct astigmatism axis is 81 % in ratio and each of the indirect astigmatism axis and the oblique astigmatism is 5%, 14% in ratio.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.1
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• pp.117-123
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• 2000

In this study, total astigmatism and corneal astigmatism were studied 328 eyes of healthy Korean for astigmatism. Total astigmatism was measured by fogging-and-dial technique, and corneal astigmatism was measured with Topcon OM-4 keratometer. Residual astigmatism was determined by a discrepancy between total and corneal astigmatism. The results were as follows: As they aged, there were a statistically significant changes in total and corneal astigmatism but not in residual astigmatism. And the amount of with-the-rule total and corneal astigmatism had a tendency to decrease, but residual astigmatism had no changes. From 30 years, total astigmatism showed a tendency to become against the rule. The average diopteric value was +0.342D in total astigmatism. +0.920D in corneal astigmatism and -0.579D in residual astigmatism.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.2
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• pp.47-59
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• 2007

When the fixation point moved far distance to near distance, the change of astigmatism type in total astigmatism showed no-changed eyes: 1,020 eyes (63.8%), changed eyes: 578 eyes(36.1 %). The change of with-the-rule into oblique-astigmatism, oblique-astigmatism into with-the-rule, against-the-rule into oblique-astigmatism of change was plenty the most respectively. In corneal astigmatism was no-changed eyes: 1,164 eyes (72.8%), changed eyes: 434 eyes(27.1%). The change of with-the-rule into oblique-astigmatism, oblique-astigmatism into with-the-rule, against-the-rule into with-the-rule astigmatism was plenty the most respectively. In residual astigmatism is no-changed eyes: 935 eyes(58.5%), changed eyes: 663 eyes(41.4%). The change of with-the-rule into oblique-astigmatism, oblique-astigmatism into against-the-rule, against-the-rule into oblique-astigmatism was plenty the most respectively. When the fixation point moved far distance to near distance, the change of astigmatism axis in total astigmatism was no-changed eyes: 761 eyes(48.5%), cyclotorsioned eyes the above 10 degrees: 837 eyes(52.3%). In corneal astigmatism was no-changed eyes: 846 eyes(52.9%), cyclotorsioned eyes the above 10 degrees : 752 eyes(47%). In residual astigmatism was no-changed eyes: 614 eyes(38.4%), cyclotorsioned eyes the above 10 degrees : 984 eyes(62.5%). The magnitude of cyclotorsion of astigmatism axis in total astigmatism was Counter clockwise rotation: 31 degrees, clockwise rotation: 20 degrees. In coneal astigmatism was Counter clockwise rotation: 25 degrees, clockwise rotation: 27 degrees. In residual astigmatism was Counter clockwise rotation: 33 degrees, clockwise rotation: 35 degrees.

• Journal of Digital Convergence
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• v.13 no.12
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• pp.285-290
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• 2015

The purpose of this study is to compare the status of eyesight according to the change of astigmatism axis in myopic astigmatism and to minimize errors in making astigmatic glasses based on accurate optometry and prescription. The subjects were 93 males and females(186 eyes) who have myopic astigmatism without any ocular disease or systemic disease. We performed comparative analysis on the status of visual acuity according to the change of astigmatism axis to 5, 10 and 15 degree in corrected eyesight 1.0. The direct astigmatism was the most common astigmatism type among the 186 eyes. After all subjects were perfectly corrected into 1.0, the change of astigmatism axis affected eyesight; The results suggested that the more change was made in astigmatism axis, the worse their eyesight would become. The main astigmatism type was changed from direct astigmatism to inverse astigmatism as age increased. The change of the astigmatism axis resulted in failing of corrected eyesight. Therefore, the convergence of examination and correction for astigmatism strength and axis is necessary when conducting refraction inspection for astigmatism.

• 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.6 no.1
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• pp.71-76
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• 2001

In this study, the variation of astigmatism axis according to the age was studied 4227 eyes of healthy eyes. The refractive errors were measured by objective and subjective refraction. The astigmatism among the total eyes was 76.5%. With-the-rule, against-the-rule and oblique astigmatism were 51.4%, 31.7% and 16.9%, respectively. The frequency of with-the-rule was the highest and against-the-rule was the lowest of all the astigmatism in the refractive error. In relation to the age and astigmatism, the with-the-rule was 68.3% in the 10's age group which was the highest among the astigmatism and the against-the-rule was 10.3% in the 50's age group and upward which was the lowest among the astigmatism. The difference in the with-the-rule and against-the-rule ratio was a little in the 30's age group. As they aged, the tendency of the with-the-rule was increased between 10's and 20's age group continually. And the tendency of the against-the rule was increased between 30's and 50's age group and upward. There was a decrease in with-the-rule and an increase in against-the-rule, with the age increase. The oblique astigmatism relationship to age could not be determined.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.2
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• pp.25-36
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• 2007

We researched the change of astigmatism power when the fixation point moved from far distance to near distance. Astigmatism power was measured by using both eyes open-view auto-refractometer. We divided the ages between 5 and 67 years old into 12 groups with 1,598 healthy eyes(male-698 eyes and female-900 eyes) without eyes problems and experiences of eyes operations. The mean power in far astigmatism showed that with-the-rule of the total astigmatism: -0.79D, with-the-rule of the corneal astigmatism: -1.07D and against-the-rule of the residual astigmatism : -0.79D were found most respectively. The correlation between cornea astigmatism and total astigmatism was y=0.7493 x + 0.5661 r=0.6510, residual astigmatism and total astigmatism was y=0.248 x - 0.5926 r=0.2598 and corneal astigmatism and residual astigmatism was y=-0.4439 x - 0.1813 r=-0.5551 in the far distance. The mean power in near astigmatism showed that with-the-rule of total astigmatism : -0.92D, with-the-rule of corneal astigmatism : -1.12D, against-the-rule of residual astigmatism : -0.87D were found most respectively. In the near distance, The correlation between corneal astigmatism and total astigmatism was y=0.6872 x + 0.5934 r=0.6204, residual astigmatism and total astigmatism was y=0.303 x - 0.6066 r=0.3165, corneal astigmatism and residual astigmatism was y=-0.46 x - 0.0626 r=-0.5322. When the fixation point moved far distance to near distance, the differences of power according to the type of astigmatism were total astigmatism: $-0.07D{\pm}0.44D$, corneal astigmatism: $-0.04D{\pm}0.54D$ residual astigmatism:$0.01D{\pm}0.53D$. Most of astigmatism refractive power was increased except for oblique-the -astigmatism. When the fixation point moved far distance to near distance, the change of astigmatism refractive power showed total astigmatism: 540 eyes(33.7%), corneal astigmatism: 638 eyes(39.9%), residual: 841 eyes(52.6%).

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.2
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• pp.105-109
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• 2001

The investigate of preschool children at 7-year-old at three kindergartens in Iksan was done by the naked visual acuity, the refractive state and cover-uncover test. Total 246 eyes were examined by the objective and subjective methods. The results were as follows: 1. Among the 246 eyes, the naked visual acuity of below the average 0.7 was 64 eyes(26%). 2. As to the distribution of refractive errors, myopic eyes and hyperopic eyes were 26.55% and 26.55%, respectively. 3. As to the type of astigmatisms, with the rule was 85.8%, against the rule was 8.9% and oblique was 5.3%. 4. The percentage of preschool children who had been tested was 13.8%. 5. In test none of children were the phoria.

• 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.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.2
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• pp.51-57
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• 2008

Purpose: This study has been conducted to know how the size and position of the circle of least confusion has an influence on the vision for minimization of asthenopia when astigmatism is corrected and appropriated prescription to provided clear vision life. Methods: The method of the study has been worked on 68 students (136 eyes) of man and woman enrolled in university of Gyeong-gi-do aged 20 to 40, who have myopic astigmatism in order to know how the corrected vision changes according to the size and position of the circle of least confusion of astigmatism, the vision has been tested by giving the vision whose astigmatic power of 0.25D and 0.50D was just reduced, low correcting the astigmatic power into 0.50D, and at the same time inserting additionally spherical power -0.25D, all under a condition that the corrected vision after completely corrected astigmatism, and the axis of astigmatism was not changed. Results: The average vision was 1.047 when the astigmatic power was fully corrected, and in low correction of 0.25D, it was 0.914, and in low correction of 0.50, it was 0.772. It has been learned that the bigger the circle of least confusion was the bigger the range of vision reduction and the corrected vision in astigmatism has correlation with the size of the circle of least confusion. It has been examined that the average vision according to position of the circle of least confusion in astigmatism was 1.047 when the astigmatic power was completely corrected and focused on the retina with state of point, and in case that the astigmatic power was 0.50D of state of low correction, that is, the circle of least confusion was focused before retina, it was 0.828, and it was also 0.826 when the astigmatic power is low corrected with 0.50D and the circle of least confusion was focused on the retina. Explained briefly, It has been examined that in case that the state of low correction of the astigmatic power was same, the vision reduction was less in the image of the circle of least confusion focused upon the retina than in the image of its being focused before the retina. Conclusions: In case that the refractive power of cylindrical lens is reduced in test of wearability in astigmatism, there needs surely an adjustment of spherical lens that can place the circle of least confusion on the retina.