• Journal of Korean Ophthalmic Optics Society
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• v.7 no.2
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• pp.47-54
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• 2002

This study as performed to survey symmetrical and asymmetrical astigmatism among 1,100 patients(2,200eyes) who were prescribed with spectacles. Of the 2,200 eyes, 59.3%(1,305 eyes) had astigmatism. Among all patients, 21.4%(235 patients) had unilateral astigmatism, 48.6%(535 patients) had bilateral astigmatism. In 1,070 eyes(535 patients) with the bilateral astigmatism, the orientation of astigmatism were 61.2% for with-the-rule astigmatism, 24.7% for against-the-rule astigmatism and 14.1% for oblique astigmatism. On the astigmatic power, -0.25~-0.50D was 47.5%, -0.75~-1.00D was 29.9%. Symmetrical astigmatism was 83.4% of the bilateral astigmatism. Asymmetrical astigmatism was 16.6% of them. From 41 to 50 years of age, 45.4% of the age had symmetrical astigmatism, 14.3% had asymmetrical astigmatism. Types of the left and the right eye in symmetrical astigmatism consisted of with-the-rule astigmatism and with-the-rule astigmatism(65.5%), against-the-rule astigmatism and against-the-rule astigmatism(25.3%), oblique astigmatism and oblique astigmatism(5.6%), etc. In asymmetrical astigmatism, with-the-rule astigmatism and oblique astigmatism was 23.6%, oblique astigmatism and with-the-rule astigmatism was 20.2%. As the results of this study, most of spectacles wearers had bilateral astigmatism that was more than unilateral astigmatism. Symmetrical astigmatism was 5 times more than asymmetrical astigmatism with no sex differences. Especially, symmetrical and asymmetrical astigmatism were more in forties than in other age groups. Over the half of symmetrical astigmatism was with-the-rule astigmatism in the left eye and with-the-rule astigmatism in the right eye. These findings will be used in prescriptions for more comfortable vision.

• Journal of Korean Clinical Health Science
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• v.9 no.1
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• pp.1478-1485
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• 2021

Purpose. To analysis of astigmatism in Korean adults from 20 to 29 years old. Methods. From January 2019 to February 2020, one hundred two subjects were performed in refraction test using the Auto-Refractometry. Results. In the type of astigmatism based on refractive error, the male's right eye was 4.26% simple myopic astigmatism and 95.74% complex myopic astigmatism, and the left eye was 2.22% simple myopic astigmatism and 97.78% complex myopic astigmatism. However, in the female's right eye, simple myopic astigmatism was 2.27%, complex myopic astigmatism was 97.73%, and left eye was simple myopic astigmatism was 2.17%, complex myopic astigmatism was 97.83%. The types of astigmatism in men and women similar to other. The mean refractive astigmatism values were -0.922±-0.798 diopter and -0.877±-0.707 diopter for male right and left eye, and -0.765±-0.599 diopter and -0.853±-0.586 diopter for female. On the other hand, the refraction values of the right and left eyes of men and women have statistical significance(p=0.000). The mean power comparative between refractive astigmatism and corneal astigmatism power were -0.186±-0.745 diopter, -1.091±-0.589 diopter in male and -1.140±-0.593 diopter, -1.140±-0.534 diopter in female. Therefore, the mean power values of the refractive astigmatism and corneal astigmatism of men and women were statistical significance(p=0.000). At the 0.75 diopter or more, which can have clinical symptoms of astigmatism power, males have 60.86% and 72.09% of the right and left eyes, and females have 47,64% and 60.10% of the right and left eyes. At 0.75 diopter or more, which can have clinical symptoms of corneal astigmatism power, males have 68.75% and 74% of the right and left eyes, and females have 86.50% and 82.35% of the right and left eyes. In the type of astigmatism axis, both men and women had a high frequency of the rule astigmatism. However, men had a high frequency of against-the-rule astigmatism and women showed a high frequency of oblique astigmatism. Conclusions. In this study, the complex myopic astigmatism and with-the rule astigmatism was the most common of all subjects. However, there was a statistical significance between right and left eyes of all subjects. The corneal astigmatism was higher refractive values in both males and females than refractive astigmatism. This study suggests that the analysis of the astigmatism can provide the useful diagnosis information for the correction of visual acuity.

• Journal of Korean Clinical Health Science
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• v.10 no.1
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• pp.1553-1558
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• 2022

Purpose: The aim of this study was to determine the association between stigmatism and amblyopia. Methods: It was a hospital based, cross-sectional retrospective study conducted in Nepal Eye Hospital. Medical record of amblyopic children aged 13 years or younger from were reviewed. Children with amblyopic eyes due to simple astigmatism were included. Relation between depth of amblyopia with magnitude and types of astigmatism, orientation of axis was determined. Out of 139 amblyopic eyes of 82 children, 93 were simple myopic astigmatism and remaining 42 were simple hyperopic astigmatism. Results: Mean age of patients was 7.38±2.61 years. Visual acuity improved by at least one line in Snellen chart in 4/5th of eyes after astigmatic correction. Moderate amblyopia was found to be present in 45% eyes while severe amblyopia in 16% of eyes. With the rule astigmatism was found to be present in 88% eyes. Mean astigmatism was 2.47±0.98D and majority of eyes (67.7%) had high astigmatism. Depth of amblyopia was not associated with magnitude of astigmatism (p > 0.05) but number of lines improved with astigmatic correction was correlated with the magnitude of astigmatism (p < 0.001). Risk of amblyopia is more in high myopic astigmatism. Conclusion: Presenting age of amblyopic children was late in Nepal. Depth of amblyopia was not associated with magnitude of astigmatism.

• 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.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.19 no.3
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• pp.377-382
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• 2014

Purpose: To investigate the effect of anterior, posterior corneal astigmatism and total corneal astigmatism on posterior corneal astigmatism by analyzing correlation. Methods: Participants were 31 patients (31 eyes) without corneal disease at the age range of 22 to 28 who had visited hospital to receive corneal refractive surgery. The total corneal astigmatism and anterior and posterior corneal astigmatism were measured using a rotating scheimpflug camera before surgery. The magnitude of astigmatism was calculated with the difference between the meridian of the steep refractive power and the flat, and With-The-Rule and inverse astigmatism were divided according to the direction of the meridian that was the steepest. Results: The averages of total corneal astigmatism and anterior and posterior astigmatism were found to be $1.13{\pm}0.76D$, $1.51{\pm}0.84D$, and $-0.59{\pm}0.17D$. The magnitude of posterior corneal astigmatism was distributed between -1.0 D and -0.25 D in all the subjects, and when the magnitude of total corneal astigmatism was set as 100, the magnitude of anterior corneal astigmatism was $142.9{\pm}29.9%$. Total corneal astigmatism indicated the highest correlation with the magnitude of anterior astigmatism (y = 0.871x-0.184, $R^2=0.982$) and high negative correlation with posterior astigmatism (y = -2.974x-0.184, $R^2=0.698$). All the subjects' anterior and posterior corneal astigmatism was classified into With-The-Rule. Conclusions: Anterior and posterior corneal astigmatism in the subjects in their 20's showed the magnitude of -3.8 D in 0.2 D and -0.25 D in -1.0 D separately, and both anterior and posterior astigmatism indicated a high percentage of With-The-Rule.

• 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.13 no.4
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• pp.151-154
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• 2008

Purpose: Javals' rule is a commonly used formula for estimating total astigmatism from corneal astigmatism. Many researchers suggested a modication of Javals' rule. Therefore, we estimated the total astigmatism on the basis of measurements of corneal astigmatism and assessed the accuracy of Javals' rule. Methods: We estimated the total astigmatism on the basis of measurements of corneal astigmatism on 108 eyes of 54 subjects of koreans in their twenties. Results: The regression of the total astigmatism from corneal astigmatism is less than 1.25 of Javals' rule, but it was equivalent to Auger's modified Javals' rule. Conclusions: The regression equation for this study was as follows: Total Astigmatism=0.79 (Corneal Astigmatism)-0.49D${\times}$90.

• Journal of Korean Clinical Health Science
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• v.1 no.1
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• pp.1-7
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• 2013

Purpose. To analysis the prevalence of the myopia and corneal astigmatism in Korea women university students. Methods. From August 2011 to December 2012, one hundreds subjects were performed in refraction test using the Auto-Keratometry. Results. The mean age of the 100 subjects (200 eyes) was $21.23{\pm}2.34$. The mean spherical refractive power was -$1.78{\pm}1.65$(OD) and -$1.83{\pm}1.67$(OS) Diopter. The mean astigmatism power was $1.22{\pm}0.96$ (OD) and $1.27{\pm}0.91$ (OS). The mean corneal astigmatism was $1.44{\pm}0.81$(OD) and $1.55{\pm}0.93$(OS). Corneal astigmatism was between 0.25 D and 1.25 D in 67.7% of eyes, 1.25 D or higher in 27.5% eyes, and less than 0.25 D in 4.8% of eyes. Astigmatism was with the rule in 65%, against the rule in 31.5%, and oblique in 3.5%. There was a statistical significance between right eye and left eye in the spherical equivalent power(p=0.002). Also there was a statistical significance between spherical power and refractive astigmatism in OD(p=0.006) and OS(0.003) and a statistical significance between corneal astigmatism and refractive astigmatism in OS(p=0.0003). However, there was not a statistical significance between spherical power and corneal astigmatism in OD(p=0.08) and OS(0.1) and a statistical significance between corneal astigmatism and refractive astigmatism in OS(p=0.48). Conclusions. In this study, these results suggested that the analysis of the refractive myopia and corneal astigmatism can provide the visual correct and useful diagnosis information for the eyewear dispensing, contact lens fitting and corneal refraction surgery.

• Journal of the Optical Society of Korea
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• v.17 no.2
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• pp.219-223
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• 2013

The purpose of this study was to determine the relationship between the spherical equivalent visual acuity (VA) and uncorrected astigmatism. On 108 emmetropic eyes, the spherical equivalent VA was measured for cross cylindrical lens (CC lens)-induced astigmatic eyes and the VA-astigmatism relation determined. On 158 astigmatic eyes, the spherical equivalent VA and corrected astigmatism were measured and the measured values were compared with the calculated values from the VA-astigmatism relation by correlation coefficient analysis. Subsequent to that, the relationship between spherical equivalent VA and uncorrected astigmatism was made. The relationship was fitted for an exponential equation. Correlation coefficient between calculated values by equation and measured values for astigmatic eyes was 0.991 (p<0.01). The relationship between the spherical equivalent VA and the uncorrected astigmatism was decided as follows (spherical equivalent VA / uncorrected astigmatism): 1.0 / 0.25 D, 0.9 / 0.50 D, 0.8 / 0.75 D, 0.7 / 1.00 D, 0.6 / 1.25 D, 0.5 / 1.50 D, 0.4 / 2.00 D, 0.3 / 2.50 D, 0.2 / 3.00 D, 0.1 / 4.00 D, and 0.05 / 4.75 D. In conclusion, the relationship table devised from this study is a useful reference for predicting uncorrected astigmatism by measurement of decimal VA in spherical equivalent.