• 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.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.74-75
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• 2002

This study investigated the relationship between refractive error and ocular elements in myopic anisometropia and isometropia. 15 visually normal myopic anisometropes (＞1.00 D interocular difference), 14 emmetropes (${\pm}$ 0.50 D), 15 low myopes (＜3.00 D) and 15 high myopes (＞3.00 D) participated in the study. Refractive error was measured by non-cycloplegic subjective refraction. (omitted)

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.1
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• pp.147-154
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• 2000

To describe the prevalence of binocular anomalies in adult Koreans. Patients included were 19 to 40 years of age, 41 males and 60 females and living in Kwang-Ju Korea. Refractive correction was estimated objectively with an autorefractometer and subjectively refined without cycloplegia. Myopia was defined as a refractive error less than -0.50 diopters hyperopia was defined as a refractive error greater than +0.50 diopters. 101 no strabismic patients who had a refractive error and a near lateral phoria(46%) and an AC/A(accommodative convergence/accommodation) anomaly(50.4%). The prevalence of a near vergence anomaly(52.5%) was higher than a near divergence anomaly(55.5%). The prevalence of a positive relative accommodation(PRA) anomaly(61.4%) was higher than a negative relative accommodation(NRA) anomaly(54.5%). According to Morgan's analysis method, patients with vergence anomaly(21.7%) were seen slightly less frequently than those with accommodative interaction anomaly(29.7%). 34.6% of patients had both vergence anomaly and accommodative interaction anomaly. These results indicate that full prescription for a refractive corrections should be considered as these can improve binocular visual function for ametropia.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.3
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• pp.249-254
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• 2012

Purpose: To investigate amount of myopic progression with increase of age for children myopes among patients of a Korean optometry clinic. Methods: It has followed up 99 children subjects (male 55, female 44) who had no ocular disease and have visited a Korean optometric clinic for mean $33{\pm}8$ months (13 to 54 months) since June of 2001. Mean age of subjects at first visit was $118{\pm}23$months. Non-cycloplegic refractive error were measured 6 times using Canon RK-3(Japan) every mean 6 months. Results: For all subjects mean of refractive errors increased -0.78 D per year from $-2.02{\pm}1.05D$ at first visit to $-4.18{\pm}1.30D$ at final visit with longitudinal study, but -0.19 D per year with cross-section study, which showed a big difference between two methods. Mean of astigmatic refractive error increased -0.15 D per year. As progression of refractive error according to ages at first visit, refractive errors increased -1.04 D per year for 6 years old, -0.9 D for 7 years old, -0.89 D for 8 years old, -0.89 D for 9 years old, -0.74 D for 10 years old, -0.74 D for 11 years old and -0.72 D for 12 years old. And it showed a tendency that the younger age was the higher progression of myopia. However it was not significantly different between each groups. Conclusions: Follow-up results for myopic children among patients of a Korean optometry clinic showed increase of -0.78 D for myopic refractive error and -0.14 D for astigmatic refractive error per year.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.3
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• pp.305-309
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• 2012

Purpose:This study was conducted to research any effect on aided distance visual acuity and refractive error changes by using smartphone at near for long term. Methods: 20($20.6{\pm}0.9$ years) young adults subjects with no ocular diseases, over 0.8 of aided distance visual acuity, normal amplitude of accommodation and normal accommodative facility agreed to participate in this study. The subjects were divided into two group, Group 1 (15 cm fixation distance) included 10 subjects and Group 2(40 cm fixation distance) included 10 subjects. Aided distance visual acuity and refractive error were measured before and after using smartphone for 30 minutes by auto-chart project (CP-1000, Dongyang, Korea), phoropter (VT-20, Dongyang, Korea), auto refractor-keratometer (MRK-3100, Huvitz, Korea). After then, the subjects looked at distance with wearing spectacles. Refractive error was measured at 5 minutes, 10 minutes, and 15 minutes later, respectively. Results: After using smartphone at 15 cm for 30 minutes, there was statistically significant reduction of aided distance visual acuity (p=0.030) and increasing myopia (p=0.001). The increased myopia was not statistically significant after 5 minutes rest (p${\geq}$0.464). However there was no statistically significant changes in aided distance visual acuity (p=0.163) and refractive error (p=0.077) after using smartphone at 40 cm for 30 minutes. Conclusions: It is recommend to keep 40 cm off the smartphone from eyes to avoid any aided distance visual acuity and refractive error changes. If smartphone is used closer than 40 cm, a rest for 5 minutes is also recommend after every 30 minutes use with smartphone to avoid any aided distance visual acuity and refractive error changes.

• Korean Journal of Community Nutrition
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• v.5 no.4
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• pp.608-614
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• 2000

The purpose of this study was to evaluate the relative importance among various biological and environmental factors on refractive errors. Various factors such as diseases, health related behavior such as drinking, smoking and exercise, as well as dietary factors were considered as a possible determinant. Surveys of 492 residents over 20 years of age in Kuri city were conducted during 1998. The survey included a refractive error test adopting a autokerato-refractometer, dietary survey using a 24 hour recall method, disease survey including blood and other diagnosis tests, and a health behavior survey using questionnaires with variables of smoking, drinking, and exercise. A stepwise logistic regression analysis was adopted to analyse the relative importance among independent variables of health behaviors, disease, and dietary factors on ametropias. As a result, in the case of myopia, liver dysfunction appeared to be the most important factors followed by the health related behavior of smoking and exercise as the second most important factors. Nutrient factors such as carotene and protein appeared to be the third most important factors. Similar results had been shown in the case of the hyperopia. In summary, liver dysfunction and the health related behaviors of drinking and smoking appeared to be more influential factors on abnormal eye sight of myopia and hyperopia than dietary factors.

• CELLMED
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• v.10 no.1
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• pp.6.1-6.7
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• 2020

In Ayurveda the eye is clarified as the most essential among all the indriyas (sensory organs), however because of changed way of life and quick pacing time we are experiencing such huge numbers of scatters, among them eye issue is most imperative as eye is the window of wellbeing. Our old acharyas (ancient scholars) have clarified about the different every day routine to be pursued for keeping up eye wellbeing, Padabhyang (foot massage) is one of them referenced in Ayurvedic dincharya (daily routine) and it has been depicted as Chakshushya (eye sight promoter) implies it improves our vision. So thinking about it, Padabhyang (foot massage) with and without snehan (oleation) was chosen for the present clinical preliminary to discover its adequacy in Timira (refractive error), result were statistically significant in subjective parameters but no change was found in objective parameter. We know, this restricted investigation has not secured every one of the angles but rather clinical preliminaries show empowering results. More study is necessary on large sample to draw the final inferences.

• Journal of Korean Clinical Health Science
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• v.5 no.1
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• pp.808-815
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• 2017

Purpose. To analyze the refractive status between urban and rural regions, of children in Korea, in the age group of 13. Methods. From October 2016 to January 2017, forty subjects( 20 male subjects, 20 female subjects; 13 years) were performed in refraction test using the Auto-Refraction. Myopia, hyperopia, astigmatism, and anisometropia were defined as spherical equivalent(SE)${\leq}-0.50$ diopters, SE ${\geq}+1.00D$, cylinder error ${\geq}0.75D$ and SE difference${\geq}1.00D$ between binocular eyes, respectively. Results. The refractive error by spherical equivalent among all subjects was myopia 76.25%, astigmatism 35%, emmetropia 16.25%, anisometropia 8.75%, and hyperopia 5%. The prevalence of myopia and astigmatism were much more common in urban than rural region although the difference was not statically significant. Emmetropia and astigmatism were much more common in rural region than urban although the difference was not statically significant. The prevalence of spherical equivalent was much common from -1.00 diopter to -4.00 diopter. On the other hand, the prevalence of myopia was much more than hyperopia. There was a statistical significance between OD and OS of rural region in the spherical equivalent power(p<.000). Also, There was a statistical significance between OD and OS of urban region in the spherical equivalent power(p<.004). Therefore, there was a significant statistical similarity between urban and rural regions on the OD and OS in the spherical equivalent power. On the other hand, There was a significant statistical similarity between urban and rural regions of the OD and OS in the astigmatism power(p<0.000). However, in the rural and urban regions there was not statistical significance in the OD and OS concerning the spherical equivalent power and astigmatism power (p>0.1). Conclusions. Myopia was the most common refractive error in Korea young children. while hyperopia was few. There was not a statistical significance as age between rural and urban at spherical equivalent power( P> 0.01). These results suggested that the analysis of the refractive status at young children can give the useful diagnosis data for the correction of visual acuity.

• Journal of Korean Ophthalmic Optics Society
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• v.16 no.4
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• pp.383-390
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• 2011

Purpose: The present study was conducted to investigate whether refractive powers of soft contact lenses were induced by the deposition of tear proteins when wearing soft contact lenses. Methods: The soft contact lenses (material: etafilcon A, hilafilcon A and comfilcon A) with refractive powers of -1.00 D, -3.00 D, -5.00 D and -7.00 D were incubated in artificial tear for 1 day, 3 days, 5 days, 7 days and 14 days, respectively. After incubation, their refractive powers were measured by wet cell method with an auto-lens meter and their protein deposited on the lenses was determined by the method of Lowry. Results: Among three types of soft contact lenses, the most protein deposition was detected in ionic etafilcon A lens material and significant change of its refractive power was manifested. In other words, refractive powers of etafilcon A lenses firstly decreased after 1 day incubation in artificial tear and then gradually increased with increasing incubation period again. The observed change in refractive powers of all diopters of etafilcon A material was beyond the scope of standard error and bigger in the lens with lower optical power. On the other hand, non-ionic hilafilcon A showed less protein deposition as much as about 20% in etafilacon A and statistically significant increase of refractive powers with increasing incubation period in artificial tear. The change in refractive power of hilafilcon A was also beyond the scope of the standard of error when incubating in artificial tear and greater in the lens with lower diopter. The least protein deposit was shown in silicone hydrogel lens material, comfilcon A as approximately 10% of it in etafilcon A, indicating less change in refractive power within the standard range of error. Conclusions: The large change of refractive powers that was beyond the scope of standard error by the deposition of tear proteins on soft contact lenses was differently detected depending on lens materials in the current study. Thus, the deposition of tear proteins induced by longer period of lens wearing may be one of the causes that induces blurred vision, suggesting that soft contact lens wearers with the amount of tear proteins may need to choose proper lens material.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.2
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• pp.261-270
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• 2014

Purpose: To study the effect of an artificially induced dioptric blur on acuity and contrast sensitivity using the $Optec^{(R)}$ 6500. Methods: Healthy 31 subjects aged $22.90{\pm}1.92$ (male 16, female 15) who were recruited from university students with 6/6 (20/20) or better corrected visual acuity and normal binocularity. They were measured objective and subjective refraction for full correction and dioptric blur using 0.00 ~ +3.00 D (+0.50 D steps) trial lenses and trial frame. They were measured binocularly visual acuity and contrast sensitivity with the $Optec^{(R)}$ 6500 (Stereo Optical Co., Inc., Chicago, Illinois, USA) under day conditions (photopic condition, $85cd/m^2$). Results: The higher dioptric blur, the less distance visual acuity and decrease rate of visual acuity. The higher dioptric blur, the less contrast sensitivity at all frequencies, and the peak of contrast sensitivity was shifted from middle frequency (6 cpd) to low frequency (1.5 cpd). When the visual acuity was best visual acuity to 0.77, there was the peak point at 6 cpd which was normal contrast sensitivity peak point. Conclusions: If the low refractive error is uncorrected or the refractive error is inappropriate, the contrast sensitivity is decreased and the peak point of contrast sensitivity frequency is shifted abnormally though small uncorrected refractive error. So it will be considered that regular eye test and decision of refractive error correction is important.