• Journal of Korean Ophthalmic Optics Society
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• v.17 no.4
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• pp.419-424
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• 2012

Purpose: We were to obtain the basic data for studying kinetic visual acuity through the comparative analysis in kinetic visual acuity, visual acuity, refractive error, pupil size, and hand reaction time for college students. Methods: We had tested the kinetic visual acuity, visual acuity, refractive error and hand reaction time using the kinetic visual acuity tester (KOWA AS-4A), the hand reaction time program and auto-refractometer for thirty-nine male and same female optometry students with more than +0.1 LogMAR visual acuity in both eyes. And the results were examined gender differences of kinetic visual acuity and the factors correlation. Results: In the measured values of male, pupil size were 6.00 mm, hand reaction time 0.23 msec, refractive error -1.66 D, visual acuity -0.07, kinetic visual acuity 0.59 and pupil size 5.86 mm, hand reaction time 0.24 msec, refractive error -2.08 D, visual acuity -0.02, kinetic visual acuity 0.46 in female. It was significant difference for kinetic visual acuity values but other factors were not. The kinetic visual acuity and left visual acuity had the highest correlation, r=-0.406. The kinetic visual acuity indicated more excellent values in the case of increasing visual acuity and decreasing myopia amount. Conclusions: It was able to see that male college students were better than female for kinetic visual acuity and the visual acuity were related to kinetic visual acuity.

• Journal of Korean Ophthalmic Optics Society
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• v.16 no.4
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• pp.425-431
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• 2011

Purpose: For better understanding refractive error in Korean children and teenagers, a follow-up study on the changes of refractive error was performed in 1~13-year-old subjects for ten years. Methods: Among the people who had visited an ophthalmologic hospital in Seoul to examine the visual acuity and to correct refractive error from 2000 to 2010 years, 223 subjects (364 eyes) having the corrected visual acuity over 0.7 had been investigated the changes of spherical equivalent power of the cycloplegic clinical refraction and manifest clinical refraction from the accumulated medical record data for ten years. Results: The changes of spherical equivalent power for ten years in 1 to 13 years old were shown the highest change at 7-year-old. And annual change of spherical equivalent power was shown the highest change at from 9-year-old to 10-year-old (-0.64${\pm}$0.64 D) followed by from 8-year-old to 9-year-old (-0.64${\pm}$0.81 D). Conclusions: The changes of refractive error for Korean children and teenagers aged 1 to 13 years in an optometric practice were shown the tendency to proceeding to myopia with age, especially the largest increase at from 7-year-old to 10-year-old, and this period is important for vision care.

• Journal of Korean Ophthalmic Optics Society
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• v.4 no.1
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• pp.7-14
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• 1999

The purpose of this study is to evaluate the relationship between ocular components and refractive error for human eye. Ocular components were measured by keratometry, phakometry, and ultrasonography. Refractive error was measured by subjective refraction on 38 subjects aged from 17 to 30. The results were as follows; 1) Refractive error and axial length, vitreous chamber depth, axial length/corneal radius were highly correlated that the correlation coefficients were 0.95, 0.96, 0.95, respectively. 2) Refractive error and corneal radius, corneal power, lens thickness were correlated with the correlation coefficients for 0.60, 0.66, 0.67 respectively. 3) There were no significant correlation between refractive error and corneal thickness.

• Journal of Korean Ophthalmic Optics Society
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• v.7 no.2
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• pp.67-71
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• 2002

To investigate the ametropia and refractive error of 364 ametropic eyes en the 182 high school students in Jeonbuk provicne, the visual acuity test was performed by the object and subject method. The results were as follows. 1. The eye types were 85.7% positive for myopia, 6.6% for emmetropia and 7.6% hyperopia, respectively. 2. The abnormal refraction eyes were 30.8% positive for simple myopia, 58.5% for myopia compound astigmatism, 7.5% for myopia simple astigmatism, and 1.8% for simple hyperopia, 1.3% for hyperopia compound astigmatism, 1.9% for hyperopia simple astigmatism, respectively. 3. The axes of astigmatism were 78.7% for astigmatism with-the-rule, 13.9% for astigmatism against-the-rule, 7.4% for astigmatism oblique, respectively. 4. As for the astigmatic power, the 0.50 < cylinder < 1.00dptr was 60.0%, the 1.00 < cylinder < 2.00dptr was 29.2%, and anything over the 2.00cylinder dptr was 10.8%. 5. As for the equivalent spheric power of myopic abnormal refraction eyes, the -0.50 < spheric equivalent < -2.00 diopter was 64.6%, the -2.00 < spheric equivalent < -6.00 dptr was 29.1% and anything over the -6.00 dptr was 6%. 6. The equivalent spheric power of hyperopic abnormal refraction eyes was 50% anything under 2.00diopter and 50% for anything over the 2.00diopter.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.4
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• pp.477-482
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• 2012

Purpose: This study is aimed at finding the conditions of ametropia of adults in the Philippines and the South Korean. Methods: The study objects were 7,695(15,390 eyes) Koreans and 2,256(4,512 eyes) Philippines who visited optic clinics and took refraction test. The distributions of their hypermetropias and myopias about astigmatisms were examined, using the method of equivalent spherical power. When astigmatisms were marked in S-C, cylinder lens diopter and astigmatism axis, presbyopic additions and pupillary distances were analyzed by comparison respectively. Results: Among ametropias of Koreans myopias and hypermetropias were 93.69% and 6.31% respectively and about ametropias of Philippines myopia and hypermetropias were 73.43% and 26.57% respectively. As for spherical equivalent power about Koreans, the results showed that Koreans marked -3.352 D about myopia and Philippines marked -2.213 D about it. There is a gap of -1.139 D between them. About hypermetropia Koreans marked 1.147 D and Philippines, 1.251 D and their gap is 0.104 D. As for ametropia of Koreans there is 49.86% in middle myopia, 32.28% about low myopia, 11.55% about high myopia, and 5.54% about low hypermetropia, 0.75% about middle hypermetropia. As for it about Philippines there is 44.53% in low myopia, 25.11% about middle myopia, 3.79% high myopia and 23.03% low hypermetropia, and 3.51% low hypermetropia respectively. As for cylinder lens there is differences of 0.194 D and 0.22 D between Korean and Philippine for both sexes. Totally Koreans have higher cylinders of 0.175 D than Philippines. As for astigmatism, Koreans have direct astigmatism, inverse astigmatism, and oblique astigmatism in their suffering sequence. As for Philippines, they have direct astigmatism, inverse stigmatism, and oblique astigmatism in their abnormal sequence, and they have higher oblique stigmatism than Koreans. As for presbyopic addition, Philippines have higher distributions than Koreans, and 0.296 D is higher in average. As for pupillary distance, Koreans have longer distance of 0.97 mm in man and 0.63 mm in women than Philippines. Conclusions: As for ametropia, Koreans and Philippines have more myopias than hypermetropias, but Philippines have more rates of hypermetropias than Koreans. And Philippines have more presbyopic additions. Koreans have higher morbidity of inverse astigmatism, and Philippines have higher morbidity of oblique astigmatism comparatively. As for pupillary distance, Koreans have longer length in the body characteristics. This shows that geographical circumstances have much to do with refraction conditions of eyes.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.1
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• pp.97-101
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• 2009

Purpose: To assess the refractive state of the westerners (male: 44, female: 62) in twenties who visited the A optical shop at Seoul. Methods: The visual acuity test was performed by the objective and subjective method. Results: The emmetropia and myoptia were 35 and 177 eyes (83.49%), respectively. About 26.76% of tested males was ametropia. Myopia compound and myopia simple astigmatism were found in 60.56% and 12.68% of tested males, respectively. However, about 43.40% of tested females was ametropia. Myopia compound and myopia simple astigmatism were 49.06% and 7.55% were found in tested females, respectively. As for the equivalent spheric power of myopic abnormal refractive eyes, the -0.5D < spheric equivalent ${\leq}$ -2.00D was 35.02% of tested westerners, the -2.00D < spheric equivalent ${\leq}$ -6.00D was 60.45% and anything over the -6.00D was 4.53%. The percentages of with-the-rule, against-the-rule and oblique astigmatism among people with astigmatism were 59.82%, 26.78% and 13.40%, respectively. The average of pupillary distance in male (63.5${\pm}$2.4 mm) was greater than that in female (59.7${\pm}$2.3 mm). Conclusions: Korean opticians were provided some useful information about making up a prescription for the westerners in twenties by this research.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.4
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• pp.465-471
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• 2013

Purpose: This study was conducted to research effects of influence factors on stereopsis of induced aniseikonia in emmetropia. Methods: 20 college students (a mean age of $22.50{\pm}2.72$ years, 14 males, 6 females) were selected as subjects and all of them had no ocular disease or systemic disease, the refractive correction of spherical equivalent within ${\pm}0.50$ D, the corrected visual acuity of 1.0 or better and the aniseikonia values less than 1% by AWAYA. Subject's dominant eye was checked by Hole in card method and contact lenses of -7.00 ~ +7.00D were fitted to cause anisometropia in dominant eye or non-dominant eye, respectively. And then aniseikonia was induced with spectacles to correct refractive error by contact lenses. Stereopsis was measured by Random Dot Stereo Acuity Test with LEA symbols$^{(R)}$ (Vision Assessment Corporation$^{TM}$, USA). Results: Stereopsis was remarkably reduced by inducing aniseikonia, with induced aniseikonia in dominant eye, with higher diopter of wearing contact lenses to induce anisometropia, with spectacles lenses correction of minus power after fitting contact lenses with plus power and in case of men. Conclusions: It should be considered to correct anisometropia that aniseikonia could cause reduction of stereopsis.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.2
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• pp.145-150
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• 2010

Purpose: In this study we investigated the correlation between the effect of myopia correction and the change of corneal eccentricity using reverse geometry lens. Methods: The 23 students (46 eyes) continuously wearing reverse geometry lens during 3 months were divided into Group I and Group II by different parameter fitting methods of wearing Reverse Geometry Lens. We measured a corneal eccentricity for Group I and Group II at $10^{\circ}$, $20^{\circ}$, and $30^{\circ}$ positions from corneal apex before wearing reverse geometry lens, 1 week, 1 month, and 3 months after wearing reverse geometry lens. We also measured an uncorrected visual acuity, a spherical equivalent, and a corneal radius and analyzed the correlation between them and the change of corneal eccentricity using statistical significance test. Results: There were the statistical significances of a change of corneal eccentricity (p=0.03, t=-2.29) for Group I and Group II at 10 position from corneal apex in a week after wearing reverse geometry lens, but were not those (p>0.05) in 1 month, and 3 months after wearing reverse geometry lens. There were the statistical significances of correlation between the change of corneal eccentricity and a corrected visual acuity, and a corneal radius, respectively. Particularly, the high correlation between the change of corneal eccentricity and a corrected visual acuity (r=-0.36, p=0.00, t=6.5), and a spherical equivalent (r=-0.72, p=0.00, t=-70.5) for Group II in a week after wearing reverse geometry lens showed. Conclusions: We knew from these results that the high correlation between the effect of myopia correction and the change of corneal eccentricity in a week after wearing reverse geometry lens represented.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.1
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• pp.45-51
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• 2013

Purpose: This study was performed to provide indicator of expected aniseikonia by correcting refractive error and to investigate influential factors on aniseikonia. Methods: 20 college students (14 males, 6 females, a mean age of $22.50{\pm}2.72$ years) were selected as subjects whose refractive error with spherical equivalent were within ${\pm}0.50$ D, corrected visual acuity were more than 1.0, and aniseikonia values by AWAYA were less than 1%. After correcting refractive error with spectacles in anisometropia induced by wearing contact lens on their dominant eye or non-dominant eye, practical measured values of aniseikonia were compared with theoretical expected values of it by the formula of spectacle magnification. Results: Practical measured values were higher than theoretical expected values in induced aniseikonia over the whole range of diopter of wearing contact lens. And there was higher measured value of aniseikonia in case of higher diopter of wearing contact lens to induce anisometropia and correcting refractive error with spectacles of (+) diopter after wearing contact lens of (-) diopter to induced anisometropia in dominant eye of women. Conclusions: It is considered that dominant eye plays more important role for visual function in induced aniseikonia and factors such as the induced eye of aniseikonia, the diopter of wearing contact lens, and gender have influenced on aniseikonia.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.1
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• pp.67-74
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• 2012

Purpose: The purpose of this study to evaluate visual acuity and refractive state and measure and analyze the components of eye's optical system in children and teenagers. Methods: With subjects of 124 (230 eyes) children and teenagers who had no eye diseases, correlation between the correlation between refractive errors and component's of eye's optical system was investigated. The spherical equivalent power of cycloplegic clinical refraction or manifest clinical refraction(SE), corneal power(CP), corneal radius(CR), axial length(AL), anterior chamber depth(ACD) and axial length to corneal radius (AL/CR) ratio were measured and analysed. Results: the SE was negatively correlated with the AL(r = -0.80, p = 0.00), the ACD(r = -0.35, p = 0.00) and the CR(r = -0.11, p=0.00) and positively correlated with the CP(r = +0.11, p=0.00). The AL was positively correlated with the AL/CR ratio (r = +0.84, p = 0.00), the ACD(r = +0.47, p=0.00) and the CR(r = +0.38, p = 0.00) and negatively correlated with the CP(r = -0.38, p=0.00). The CR was negatively correlated with CP(r = -1.00, p = 0.00), the AL/CR ratio(r = -0.19, p = 0.00) and the ACD(r = -0.06, p = 0.39). The CP was positively correlated with the AL/CR ratio(r = +0.19, p = 0.00) and the ACD(r = +0.06, p = 0.39). The ACD was positively correlated with the AL/CR ratio(r = 0.53, p = 0.00). Conclusions: the highest change of refractive errors was shown that the AL/CR ratio was a very important indicator for diagnosing the refractive errors of the children and teenagers.