• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.8
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• pp.3933-3940
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• 2013

The purpose of present study was to determine the frequency of RA with age and to investigate the age-related trends and changing-factors in RA, CA and IAs. The refractive power of the eye and the power of corneal anterior surface were measured with auto-refractor among 1,017 inhabitants aged 5 to 59 years in Cheongju in July 2010. The overall frequency of RA was 22.7%, and frequency of RA increased from 8.9% in 5~9 years age group to 36.8% in 20~29 years age group. It then dipped to 19.2% in 40~49 years age group but increased again 28.6% in 50~59 years age group. $J_{45}$ components for RA, CA, and IAs were fairly stable in different age groups, the changes in $J_0$ components for both RA and CA appeared to be decreased after age of 30 years. In addition, the refractive power on the vertical direction was changed slightly with age, but the refractive power on the horizontal direction was changed significantly with age. It was expected that the change in the frequency of astigmatism with age was due to the change in the refractive power of horizontal meridian.

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.2
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• pp.53-57
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• 2001

The corneal structure and function changes somewhat with aging. We were performed the analysis of women college students on the base curve, power, and astigmatism axis of the cornea by keratometer. All women subjects were between the ages of 19 and 20 years. On the corneal base curve. the right eye of the ages of 19 was 7.64 mm in vertical and 7.81 mm in horizontal. But, the left eye was 7.65 mm in vertical and 7.83 mm in horizontal on the other hand, the right and left eye of the ages of 20 was 7.72 mm in vertical and 7.75 mm in horizontal. On the corneal diopter power, the right eye of the ages of 19 was 44.21 diopter in vertical and 43.32 diopter in horizontal. But, the left eye was 44.23 diopter in vertical and 43.24 diopter in horizontal. On the other hand, the right eye of the ages of 20 was 43.67 diopter in vertical and 43.62 diopter in horizontal. But, the left eye was 43.73 diopter in vertical and 43.6 diopter in horizontal. According to the corneal astigmatism axis style, the right eye of the ages of 19 have 83% positive for with the rule astigmatism, and 16% positive for against the rule astigmatism. But, the left eye of the ages of 19 have 86% positive for with the rule astigmatism, and 12% positive for against the rule astigmatism. On the other hand, the right eye of the ages of 19 have 56% positive for with the rule astigmatism, and 44 % positive for against the rule astigmatism. But, the left eye of the ages of 20 have 56% positive for with the rule astigmatism, and 41% positive for against the rule astigmatism. According to the diopter power of corneal astigmatism. The right eye of the ages of 19 have 36% positive for behind 1 diopter and left eye have 31%. But, the right and left eye of the ages of 20 have 37.5%. The right and left eye of the ages of 19 have 42% positive for 1 diopter, and the right eye of the ages of 20 have 34.4% positive for 1 diopter and the left eye have 43.8%. The right eye of the ages of 19 have 12% positive for 2 diopter and left eye have 22%. But, the right eye of the ages of 20 have 15.6% positive for 2 diopter and the left eye have 12%. The right eye of the ages of 19 have 4% positive for 3 diopter and left eye have 3%. But, the left eye of the ages of 20 have 3% positive for 3 diopter and the left eye have 6%. On the other hand, the right eye of ages of 19 have 6% positive over 4 diopter, and the left eye have 2%. But, the right eye of ages of 20 have only 9% positive over 4 diopter.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.2
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• pp.455-462
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• 2004

In this paper, we measured and analysised the power change of tear lens for 85 patients - 170 myopia eyes - who are fitted using RGP lens, considering the BGR of RGP lens, the corneal astigmatism power, and corneal curvature. We got the following results from these experiments; 1. When the BCR of RGP lens changes, the diopters of tear lens of "on-k", 0.05Pt, 01.0Ft, 0.05St, and 0.10St are -0.25D, -0.46D, -0.63D, +0.07D, and +0.26D, respectively. 2. When the corneal astigmatism power changes, the diopters of tear lens of group below 0.75D, group of 1.00D~1.25D, group of 1.50D~1.75D, and group over 2.00D in "on-k" state, are -0.25D, -0.18D, -0.09D, and -0.39D, respectively. 3. When the corneal astigmatism power changes and the BCR of test lens is changed by 0.05mm step, the change values of tear lens diopter for 0.05St and 0.05Ft approximate to ${\pm}0.25D$, while these for 0.10St and 0.10Ft don't approximate to the value below ${\pm}0.25D$.[are irregular value below ${\pm}0.25D$.] 4. When the corneal curvature and the HCR of RGP lens change, the diopters of tear lens of group below 7.50mm, group of 7.55~7.80mm, group of 7.85~8.20mm, and group over 8.25mm in "on-k" state, are -0.40D, -0.11D, -0.20D, and -0.19D, respectively. 5. When the BCR of test lens is changed by 0.05mm step and the corneal curvature increases, the change values of tear lens diopter decrease, while these over 8.25mm are mean value ${\pm}0.17D$ and the value below ${\pm}0.25D$.

• The Korean Journal of Vision Science
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• v.20 no.4
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• pp.543-551
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• 2018

Purpose : The purposes of this study were to evaluate the changes of intraocular pressure according to corneal ablation amount after corneal refractive surgery and the changes of intraocular pressure according to refractive errors before corneal refractive surgery. Methods : The mean age of adults who underwent LASIK corneal refractive surgery were $37.34{\pm}7.42years$, and 108 adults(48 males, 60 females) were participated in this study. Refractive errors, intraocular pressure, and corneal ablation amount were measured using an autorefractor, a noncontact tonometer, and an excimer laser. All test values were considered statistically significant when p<0.05. Results : The mean intraocular pressure before corneal refractive surgery was $15.08{\pm}2.60mmHg$ in males and $14.16{\pm}2.67mmHg$ in females. The decrease of intraocular pressure after corneal refractive surgery were 4.22mmHg in males and 3.61mmHg in females. Spherical equivalent power were $-3.89{\pm}2.17D$ in males and $-4.45{\pm}2.92D$ in females before corneal refractive surgery, and $-0.10{\pm}0.46D$ in males and $-0.04{\pm}0.46D$ in females after corneal refractive surgery. The corneal ablation amount after corneal refractive surgery were statistically significant, with $53.95{\mu}m$ in males and $61.26{\mu}m$ in females. There was significant correlation between corneal ablation amount and decrease of intaocluar pressure(r=0.2299, p<0.001). As the growth of corneal ablation amount in males, the decrease of intraocular pressure was significantly increased. As the growth of refractive error, the amount of decrease in intraocular pressure was also significant. The decrease of intraocualr pressure were $3.04{\pm}2.18mmHg$ in low refractive error, $4.10{\pm}2.16mmHg$ in middle refractive error, and $4.65{\pm}3.29mmHg$ in high refractive error. Conclusion : We found that intraocular pressure decreased after corneal refractive surgery by noncontact tonometer and the change of intraocular pressure which is an important index for glaucoma diagnosis, may affect the judgment of eye disease. We think that a preliminary questionnaire whether corneal refractive surgery is necessary for the measurement of intraocular pressure.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.2
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• pp.203-209
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• 2004

Physiological accommodation in aphakia has been reported 0.50D. Also, accommodation appears in pseudo-crystalline lens. However accommodation was not clear how to works in the eyes. Therefore, the purpose of this study is that accommodation has been affected to changes of axial length and corneal refractive power when the accommodative stimulus was taken 10 diopters to person who has pseudo-crystalline lens. To determine of the accommodative response of pseudo-phakic patients who had no side effects over 2 months, we have measured the axial length, corneal refractive power in 48 patients(96 eyes). When the accommodative stimulus was taken about 10 diopters, the axial length increased by $0.05{\pm}0.06mm$ and corneal refractive power increased $0.04{\pm}0.24$ diopter. The changes of axial length in the myopia was increased by $0.19{\pm}0.18D$, emmetropia was increased by $0.12{\pm}0.16D$ and hyperopia was $0.10{\pm}0.19D$. The results of measurement revealed that the mean value was increased $0.03{\pm}0.13D$ in the myopia, and increased $0.21{\pm}0.13D$ in the emmetropia, and decreased $0.02{\pm}0.34D$ in the hyperopia.

• 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 Digital Convergence
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• v.14 no.11
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• pp.435-440
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• 2016

The aim of study was to provide the preliminary data to find out characteristics of the difference between both refractive errors through analysis of ocular components variation. We measured spherical equivalent power and corneal radius with KR-8800, and axial length and anterior chamber depth with IOL Master, and the difference of measuring values between the right eye and left eye was applied as the absolute values in 100 adults aged 20~59 years. In all participants, the most common results showed that spherical equivalent power was $-1.83{\pm}2.17D$, axial length was 23.00~24.99mm, corneal radius was 7.50~7.89mm, and anterior chamber depth was 3.60~4.09mm. There are significant correlations between both eyes in axial length and anterior chamber depth with the difference of both spherical equivalent power. The difference of both axial lengths was the biggest with the difference of both refractive errors, and shown the highest correlation. The convergence complex study through classification by aspects is needed since the difference of both refractive errors is closely related with ocular components variation, and poor visual function would be caused by the difference of both refractive errors.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.4
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• pp.473-479
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• 2013

Purpose: This article tried to find the changes of the eye and a correlation depending on watching a smartphone and taking in alcohol. Methods: This paper conducted the refraction inspection, the radius of corneal curvature, tonometry and the corneal thickness measurement and analysis for 31 persons (18 males and 13 females) who have healthy drinking habit, not having the medical history of taking medicine related with disorders of the eye, a mental disease, systemic disease and alcohol metabolism. Results: Of respirations depending on watching a smartphone, the alcohol concentration was significantly decreased in 15 minutes, 30 minutes, 45 minutes, 60 minutes and the convalescent stage. (p<0.01, p<0.001) As the result of comparing the refraction inspection after and before watching a smartphone when drinking alcohol, there was a significant difference in the cylindrical power and the axis. (p=0.005, p=0.001) The change of intraocular pressure depending on watching a smartphone after drinking alcohol was decreased significantly from 30 minutes (p<0.001), and watching a smartphone didn't have any significant effect on the corneal thickness depending on the elapsed time from when drinking alcohol. Conclusions: Watching a smartphone and taking in alcohol had a significant effect on the cylindrical power and the axis. Watching a smartphone and taking in alcohol which may cause the visual function-strain are the factors that need to consider before the refraction inspection.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.4
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• pp.389-394
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• 2012

Purpose: The purpose of this study was to examine the corneal topographical changes associated with the wearing of everted silicone hydrogel soft lenses. Methods: The shape and fluorescein pattern of everted silicone hydrogel lenses were investigated. The subject wore the silicone hydrogel everted lenses overnight for 8 hours. Objective refractive error and corneal shape were evaluated at baseline, 1, 2, 3, 5, and 7 days after lens wearing and 1,2,3, and 4 days after discontinuation of lens wear. Results: The Fluorescein pattern of everted silicone hydrogel lenses was similar to the reverse geometry lenses with pressure profile. Objective refractive error(sphere power) and corneal refractive power were decreased and corneal shape had changed during the everted silicone hydrogel lenses wear and recovered during the 4 days of discontinuation. Subject experienced no discomfort associated with the everted silicone hydrogel lenses. Conclusions: It appears that everted silicone hydrogel lenses are capable of inducing significant changes in corneal topography, with overnight wear. Further study must be done to help understand these changes to develop a predictable and effective way of using soft contact lenses for corneal reshaping.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.2
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• pp.195-199
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• 2010

Purpose: This study was to investigate the relevance between refractive and anatomical changes temporarily on the eyes after alcohol ingestion. Methods: Eight subjects (16 eyes) which were $24.5{\pm}1.5$ aged males drunk the alcohol of 0.42 g per kg of body weight within 30 minutes. Refractive errors, the radius of corneal curvature, corneal thickness, pupillary size, intraocular pressure, and the length of the ocular axis at 1 h, 4 h, and 24 h after alcohol ingestion were compared with them of non-alcoholic state. Results: At 1 h after alcohol ingestion, breath alcohol concentration was the highest (p<0.001), more negative spherical power was needed (p<0.05) for correction, pupillary diameter was decreased (p<0.05), intraocular pressure was decreased (p<0.001), and the length of the ocular axis was increased compared with each one of non-alcoholic state. At 4 h after alcohol ingestion, all anatomical changes were the same tendency as at 1 h after alcohol ingestion. But at 24 h after alcohol ingestion, both refractive changes and anatomical changes were not significant compared with them of non-alcoholic state. Conclusions: Temporary changes of refractive error after alcohol ingestion may be related with decrease of intraocular pressure and increase of the length of ocular axis.