• Journal of Korean Ophthalmic Optics Society
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• v.18 no.1
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• pp.85-91
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• 2013

Purpose: The purpose of this study is to investigate difference between manifest refraction (MR) and cycloplegic refraction (CR) with age and myopic value. Methods: Manifest and cycloplegic refractions were carried out on the patients of 229 myopic patients ($25.3{\pm}11.9$ years old). Results: The average results from a pre- and a postcycloplegic refraction showed a reduction of 0.19 D in myopia, 0.02 D in astigmatism and $1.85^{\circ}$ in astigmatism direction. Change of myopic value was higher in 30~40 age. Total 73 eyes of 229 patients who showed 0.50 diopter (D) in spherical, and a high degree of myopia group showed a higher discrepancy rate. Conclusions: The results found in the comparison of the value of the manifest refraction and cycloplegic refractions showed changes of myopic value was not significant with age of patient, but the group of high degree of myopia showed higher discrepancy rate.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.4
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• pp.145-149
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• 2008

Purpose: To study the difference between refractive errors obtained from manifest refraction (MR) and cycloplegic refraction (CR) in first-time spectacle wearers. To study the difference between manifest refractive errors and cycloplegic refractive errors in first-time spectacle wearers. Methods: From January 2002 to December 2002, manifest and cycloplegic refractions were carried out on the patients who visited an ophthalmology clinic for a spectacle prescription for the first-time. The patients were 509 male and 499 female patients aged between from 3 to 15 years old. Results: The cycloplegic refraction showed a less myopia and a more hyperopia compared with the non-cycloplegic refraction. The differences were more in female patients. The CR showed a less myopic and a more hyperopic refractive errors than the MR. The differences were more in female patients. The average results from a pre- and a post-cycloplegic refraction showed a reduction of -0.22D in male, and -0.20D in female for the myopic group. For the myopic group, the myopic refractive errors by MR were -0.22D in male and -0.20D in female higher than the refractive errors by CR. Hyperopic group showed an increase of +0.37D in male, and +0.56D in female. For hyperopic group the hypropic refractive errors by CR were +0.37D in male and +0.56D in female higher than the refractive errors by CR. This difference between the results of a preand a post-cycloplegic refraction was more if the patients were younger. This difference between refractive errors by MR and by CR showed the younger the more and the proportions of pseudo-myopia and or latent hyperopia were also higher with younger patents age. The amounts of with-the-rule astigmatism and the oblique astigmatism were increased for the post-cycloplegic refraction in the CR refraction. Simple astigmatism reduced, but there was no difference found in the amount of astigmatism. The prevalence of simple astigmatism reduced, but there was no difference in the amount of astigmatism. Conclusions: The difference between manifest refraction and cycloplegic refraction was more in younger group. The difference of refrative error between by MR and CR increases with ageing decrease. Pseudo-myopia and latent hyperopia was also found in the younger group. Simple astigmatism reduced after cycloplegic refraction, there was no difference found in the amount of astigmatism. The prevalence of simple astigmatism reduced, but there was no difference in the amount of astigmatism.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.2
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• pp.123-130
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• 2010

Purpose: The study was conducted to compare the values of auto-refraction, manifest refraction and cycloplegic refraction in school-aged children. Methods: One hundred five myopic school children ranged from 6 to 14 years old (210 eyes, $10.28{\pm}1.59$ years old) were recruited and noncycloplegic auto-refraction (AR) and manifest refraction (MR) were conducted and then underwent cycloplegia and refractive status (CR) again with the auto-refractometer. Results: Refractive powers measured by AR, MR, and CR were highly correlated. However, spherical and cylindrical powers of the subjects measured by AR were measured higher negative power than in CR (p<0.001). From 210 eyes, the discrepancy rate in the spherical and cylindrical powers were 40 eyes (19%) and 19 eyes (9%) of the total subjects, respectively and the differences between noncycloplegic and cycloplegic refractions were higher with the spherical and cylindrical powers increasing. Conclusions: The use of the autorefractometer in children with negative spherical power without cycloplegia may overestimate the actual myopia that subjective refraction is the most important in prescription for the eyeglasses and regression equations would be used to prognose the cycloplegic refraction from the auto-refraction as the basic data for the subjective refraction.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.3
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• pp.293-298
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• 2012

Purpose: We compared static retinoscopy in eyes opened with cycloplegic refraction depending on the hyperopia for school-aged children. Methods: There were 59 eyes (30 patients) who were divided into 3 groups - the mild hyperopia (+0.25 D ~ +1.00 D), moderate hyperopia (+1.25 D ~ +2.00 D) and high hyperopia (+2.25 D or more). They all had 0.8 visual acuity or more. Autorefraction and retinoscopy were performed prior to cycloplegic refraction, and then copmared with manifest refraction and cycloplegic refraction. Results: Hyperopia measured with static retinoscopy tends to be measured higher than manifest refraction for school-aged children. Changes of spherical power was statistically significant (p < 0.001). Changes of astigmatism was not statistically significant (p > 0.05). Conclusions: The difference between cycloplegic refraction and static retinoscopy was not significant for hyperopic school-aged children. The use of retinoscopy was limited for opticians because of legal constraints. The usage of static retinoscopy in eyes opened for optician should be generalized under the conditions not using the cycloplegic.

• Korean Journal of Ophthalmology
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• v.32 no.6
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• pp.497-505
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• 2018

Purpose: To evaluate and compare published methods of calculating intraocular lens (IOL) power following myopic laser refractive surgery. Methods: We performed a retrospective review of the medical records of 69 patients (69 eyes) who had undergone myopic laser refractive surgery previously and subsequently underwent cataract surgery at Samsung Medical Center in Seoul, South Korea from January 2010 to June 2016. None of the patients had pre-refractive surgery biometric data available. The Haigis-L, Shammas, Barrett True-K (no history), Wang-Koch-Maloney, Scheimpflug total corneal refractive power (TCRP) 3 and 4 mm (SRK-T and Haigis), Scheimpflug true net power, and Scheimpflug true refractive power (TRP) 3 mm, 4 mm, and 5 mm (SRK-T and Haigis) methods were employed. IOL power required for target refraction was back-calculated using stable post-cataract surgery manifest refraction, and implanted IOL power and formula accuracy were subsequently compared among calculation methods. Results: Haigis-L, Shammas, Barrett True-K (no history), Wang-Koch-Maloney, Scheimpflug TCRP 4 mm (Haigis), Scheimpflug true net power 4 mm (Haigis), and Scheimpflug TRP 4 mm (Haigis) formulae showed high predictability, with mean arithmetic prediction errors and standard deviations of $-0.25{\pm}0.59$, $-0.05{\pm}1.19$, $0.00{\pm}0.88$, $-0.26{\pm}1.17$, $0.00{\pm}1.09$, $-0.71{\pm}1.20$, and $0.03{\pm}1.25$ diopters, respectively. Conclusions: Visual outcomes within 1.0 diopter of target refraction were achieved in 85% of eyes using the calculation methods listed above. Haigis-L, Barrett True-K (no history), and Scheimpflug TCRP 4 mm (Haigis) and TRP 4 mm (Haigis) methods showed comparably low prediction errors, despite the absence of historical patient information.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.1
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• pp.99-104
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• 2010

Purpose: Difference of refraction result from the method of autorefraction and iTrace were investigaged for the children of elementary school in Asan City. In iTrace method. exclusion of accommodation without cycloplegia was used. Methods: Manifest refractive stale of 42 eyes of 12~13 years old were measured using autorefractor and iTrace. Refractions of far (more than 5 m) and ncar (30 cm) vision were measured using iTrace. All data showed that the spherical equivalent were classified as being in the group 1 (-0.50D < ~ < +1.00D) and 2 (below -0.50D) according 10 refractive errors. Results: Mean spherical equivalent using autorefractor and iTrace (far and near vision) were -1.08D, -0.29D and -2.34D, respectively (p<0.01). Compared with the far vision using iTrace, autorefraction was measured the myopia with -0.50D ~ -1.00D in 52.4% of total eyes. Autorefraction also statistical significant were measured a more myopia than the far vision using iTrace in group I and 2. Conclusions: The difference of refractive errors between autorefraction and iTrace, objective refraction were measured with far vision of more than 5 m were -0.79D. Autoreftaction showed statistically decreased refraction errors than iTrace with far vision.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.3
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• pp.219-225
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• 2010

Purpose: Usefulness in predicting the power of spherical rigid gas-pearmeable (RGP) lenses prescription using dioptric power matrices and arithmetic calculations was evaluated in this study. Noncycloplegic refractive errors and over-refractions were performed on 110 eyes of 55 subjects (36 males and 19 females, aged $24.60{\pm}1.55$years) in twenties objectively with an auto-refractometer (with keratometer) and subjectively. Tear lenses were calculated from keratometric readings and base curves of RGP lenses, and the power of RGP lenses were computed by a dioptric power matrix and an arithmetic calculation from the manifest refraction and the tear lens, and were compared with those by over-refractions in terms of spherical (Sph), spherical quivalent (SE) and astigmatic power. Results: The mean difference (MD) and 95% limits of agreement (LOA=$MD{\pm}1.96SD$) were better for SE (0.26D, $0.26{\pm}0.70D$) than for Sph (0.61D, $0.61{\pm}0.86D$). The mean difference and agreement of the cylindrical power between matrix and arithmetic calculation (-0.13D, $-0.13{\pm}0.53D$) were better than between the others (-0.24D, $0.24{\pm}0.84D$ between matrix and over-refraction; -0.12D, $0.12{\pm}1.00D$ between arithmetic calculation and over-refraction). The fitness of spherical RGP lenses were 54.5% for matrix, 66.4% for arithmetic calculation and 91.8% for over-refraction. Arithmetic calculation was close to the over-refraction. Conclusions: In predicting indications and powers of spherical RGP lens fitting, although there are the differences of axis between total (spectacle) astigmatism and corneal astigmatism, Spherical equivalent using an arithmetic calculation provides a more useful application than using a dioptric power matrix.

• 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.15 no.4
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• pp.389-397
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• 2010

Purpose: This study was to investigate the changes of refractive error and astigmatism associated with age in Korean subjects between the ages of 6 and 80 years during 10-year period. Methods: 220 normal subjects (345 eyes) who visited ophthalmic clinic was recruited and followed for 10 years between 1999 and 2009, cycloplegic manifest refraction being performed annually. Visual acuity was tested on a Han's chart. Results: The mean 10-year change in the spherical equivalent refraction (SER) of age 6 to 10 years old and 10 to 20 years was -3.649D and -2.165D respectively. There was no change of refractive error in age 21 to 40 years. The myopic shift decreased with age from 41 up to 69 years but increased slightly in patients 70 years and older; the hyperopic shift showed the opposite trend. The distribution of refractive error over the 10 years in aged 6 to 10 and 11 to 20 years was shifted myopic. The incidence of medium (> -3.01D) to high myopia at age 6 to 10 years was 4.8% and after 10 years was 62.5%. The 10-year change of astigmatism axis was in "with the rule" direction for younger age group and in a "against the rule" direction for older subjects. Conclusions: This study has documented refractive error changes in Korean subjects and confirmed reported trends of myopic shift from age 6-20 years and hyperopic shift before age 70 years and a myopic shift thereafter. The axis of astigmatism turns to "against the rule" after 40's.

• Yonsei Medical Journal
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• v.59 no.9
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• pp.1115-1122
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• 2018

Purpose: To investigate biomechanical properties of the cornea using a dynamic Scheimpflug analyzer according to age. Materials and Methods: In this prospective, cross-sectional, observational study, participants underwent ophthalmic investigations including corneal biomechanical properties, keratometric values, intraocular pressure (IOP), and manifest refraction spherical equivalent (MRSE). We determined the relationship of biomechanical parameters and ocular/systemic variables (participant's age, MRSE, IOP, and mean keratometric values) by piecewise regression analysis, association of biomechanical parameters with variables by Spearman's correlation and stepwise multiple regression analyses, and reference intervals (RI) by the bootstrap method. Results: This study included 217 eyes of 118 participants (20-81 years of age). Piecewise regression analysis between Corvis-central corneal thickness (CCT) and participant's age revealed that the optimal cut-off value of age was 45 years. No clear breakpoints were detected between the corneal biomechanical parameters and MRSE, IOP, and mean keratometric values. Corneal velocity, deformation amplitude, radius, maximal concave power, Corvis-CCT, and Corvis-IOP exhibited correlations with IOP, regardless of age (all ages, 20-44 years, and over 44 years). With smaller deformation amplitude and corneal velocity as well as increased CorvisIOP and Corvis-CCT, IOP became significantly increased. We provided the results of determination of confidence interval from RI data using bootstrap method in three separate age groups (all ages, 20-44 years, and over 44 years). Conclusion: We demonstrated multiple corneal biomechanical parameters according to age, and reported that the corneal biomechanical parameters are influenced by IOP.