• 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.14 no.4
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• pp.89-96
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• 2009

Purpose: This study was to investigate and analyze understanding and knowledge of the eye in biological science education for middle and high school students in Busan. Methods: A total of 821 middle and high school students from four different schools participated by self-administered questionnaire test. The results were compared and analyzed by grade and gender. Results: In the survey of the understanding about the eye in the biological science curriculum, the results indicated that the more learning of the eye in biological science lecture led to the more understanding of the role of the eye. The difference of understanding the eye between learned and unlearned students in biological sciences lecture was significant (p<0.01). In the survey of the knowledge of the eye, students did not know about myopia and astigmatism (average value <50). Conclusions: As biological science education is one of the major factors to understand the role of the eye, this result suggests that more information about the eye in the curriculum of biology is included.

• Journal of Korean Ophthalmic Optics Society
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• v.16 no.3
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• pp.313-317
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• 2011

Purpose: This study was to assess prevalence of refractive errors and uncorrected refractive errors in elementary school children in Mokpo and uncorrected refractive errors were to be used as the basic data. Methods: Vision tests were conducted on 400 subjects of 1st~6th grades at 3 elementary schools in Mokpo city, and subjective, objective refraction test were also performed to survey uncorrected refractive errors. Results: The prevalence of myopia was 256, 64% of total subjects, Hyperopia was 21, 5.3%, astigmatism was 19, 4.8%. The prevalence of uncorrected refractive errors were increased as higher grade and more oculus dexter higher than oculus sinister. Conclusions: Vision impairment which need an accurate vision correction for elementary school students requires the regular examination and actively correction in order to protect the elementary school students for basic welfare.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.2
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• pp.199-206
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• 2014

Purpose: The present study was aimed to investigate the correlation between higher-order aberration and myopic degree by the analysis of fluctuation of high-order aberration according to the change of myopic degree in certain ranges of myopia and astigmatism. Methods: The high-order aberration in a total of 992 eyes was analyzed by using a LADARWave device employing Hartmann-Shack system, and the relation between high-order aberration and myopia by the change of myopic degree through manifest refraction test. Results: In all subjects, spherical aberration and total coma aberration were significantly increased by the increase of myopic degree, however, trefoil aberration and astigmatic aberration and tetrafoil aberration were decreased. With the group of lower myopic degree, the change of coma aberration was greater by myopic degree and its change was significantly different. The change of spherical aberration by myopic degree was greatly large in the a group of -3.00 D or more and the group of -6.00 D or more where as its change was not large in the group of lower than -3.00 D. The significant decrease of coma aberration was observed only in the group of astigmatic degree of -1.00 D or less when analyzing the correlation between the higher-order aberrations and myopia in the certain groups of astigmatic degree. In the case of spherical aberration, the significant change was shown in all astigmatic groups, however, its increase was larger with the increase of myopic degree in lower degree of astigmatism. The consistent relationship in variations of horizontal and vertical coma aberration in certain myopic and astigmatic groups was neither established nor statistically significant. Conclusions: It is concluded that the correlation between the higher-order aberration and low-order aberration obtained from the results of the present study can help the understanding related to vision quality and the improvement of vision quality.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.4
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• pp.449-456
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• 2013

Purpose: The present study aimed to investigate the effects of corneal eccentricity and shape on the rotational pattern of toric soft lens by the postural change of lens wearers. Methods: The corneal eccentricity of 41 eyes (aged 20s) having -1.0 D with-the-rule corneal astigmatism (WRCA) was measured, and then toric soft lenses were fitted with the amount of total astigmatism. In lying and straight postures, the rotation of toric soft lenses was recorded by a camera attached to slitlamp and analyzed. Results: Most toric soft lens designed with accelerated stabilization rotated to the temporal direction, which was the lying position direction, regardless of corneal eccentricity, and some lenses rotated to the nasal direction for high corneal eccentricity and corneal type of asymmetric bowtie. There was no correlation between the amount of rotation and corneal eccentricity right after of contact lens wearing in straight and lying posture, however, the amount of rotation was the greater for the cornea with the higher eccentricity after the subjects laying down for some period. The speed of lens rotation started to decrease after the subjects laying down, but the speed was not different according to corneal eccentricity difference. The amount of lens rotation for symmetric and asymmetric bowtie-typed corneas increased more than it for oval-typed cornea, and it was same even with time elapsing. The speed of lens rotation in lying posture was the slowest in asymmetric bowtie-typed cornea compared with other corneal types. Conclusions: From the present study, it was revealed that the rotational pattern of toric soft lens was affected by corneal eccentricity and corneal shape when the wearer's posture changed. Thus, it should be considered for the development of the fitting guideline and the design of toric soft lens.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.3
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• pp.1-5
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• 2007

This is a succeeding article of J. Korean Optalmic Optics Society vol. 11(2) pp. 121-129(2006) [Research about the distribution of refractive errors in distinction of gender and at age of Kyonggi province's partial area]. The former article showed age-specific distribution of myopia, hyperopia and astigmatism which generally appears in refractive errors. This paper aimed to investigate the change of refractive power and prevalence of refractive errors by age. Total 928 subjects were sampled and their refractive errors were determined using auto refractometer. As the results, change of refractive power of subjects appeared at the age about 40, and suddenly reduced over 46 years resulting in (+)refractive power at their fifties. Relative risks of refractive errors of myopia increased in younger subjects but the risks decreased in older subjects (over 46 years). On the other hand, the risks of hyperopia decreased as the age of subjects increase, but could increase to 0.24 (95% CI: 0.07-0.88) after 36 years. This results showed that presbyopia might progress more early when people were before 40 years.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.4
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• pp.503-507
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• 2013

Purpose: This study was to design wide angle mobile camera corrected optical distortion for peripheral area, which were reduced optical distortion and TV distortion by using 4 aspherical lenses. Methods: The optical design was satisfied with ${\pm}1%$ optical distortion in viewing angle of $95^{\circ}$ and total length of optical system was less than 4.5 mm which was considering a thickness of mobile camera. 1/3.2 inch (5M) CCD sensor was used in the optical system and set design condition to satisfy MTF which was over than 20% in 140 lp/mm. Results: Optimized wide angle mobile camera showed ${\pm}1%$ optical distortion in full field of $95^{\circ}$ viewing angle and TV distortion was 0.46% so that distortion of peripheral area was reduce. MTF showed over than 20% in every field. Ray aberration and astigmatism were small amount so that it showed stable performance. Conclusions: Obtain wider and clearer view which is reduced image distortion of surrounding area via optical method in wide angle mobile camera which has wider view angle than current mobile camera. And it was able to fix a demerit when it occurred via software correction. It is able to apply to study of camera which is related to spectacles.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.9 no.1
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• pp.146-158
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• 1996

We observed 79 patients, who visited the Department of Oph. & Otorhinolaryngology in Oriental medicine of Kyung Hee University Medical Center from July 1995 to June. 1996, with the complaint of decreased visual acuity. The results were as follows. 1. In the incidence of decreased visual acuity, men's was $46.84\%$(37 cases) and women's was $53.16\%$(42 cases), which showed that more women were suffering decreased visual acuity than men. In the incidence of myopic ametropia and astigmatic ametropia among the total patients, men's was $44.62\%$(29 cases) and $37.50\%$(9 cases) each, and women's was $55.38\%$(36 cases) and $62.50\%$( 15 cases) each, which also showed that more women were suffering myopia and astigmatism than men. 2. The average age of patients was 11.08 years at the first visit. The most were the patients from 6 to 15 years old, with 63 cases($79.74\%$). 3. The age of onset in the decreased visual acuity was mainly 6∼10 years with 45 cases($56.96\%$). In the case of myopic ametropia and astigmatic ametropia, the age of onset was also mainly 6∼10 years with 65 cases($60.00\%$), and with 12 cases($50.00\%$) each. 4. In ABO blood type, the frequency was, A type, O type, B type and AB type in order. In men, O type was the most, while in women, A type. 5. In the liking for cool or warm food or tepidity, the liking for cool food was the most in both men and women. 6. The type of decreased visual acuity was mainly myopic ametropia with 65 cases($82.28\%$). Astigmatic ametropia was $30.38\%$ with 24 cases, hyperopic ametropia $2.53\%$ with 4 cases, and the decreased visual acuity accompanied by amblyopia $7.59\%$ with 4 cases. 7. At the first visit, the average visual acuity of O.D. was 0.29 and that of O.S.. 0.24, which showed that O.S.. is worse than O.D.. The visual acuity below 0.2 was the most, $63.29\%\;in\;O.D..\;72.15\%$ in O.S.. 8. In the treatment period, 4∼7 weeks occupied $35.44\%$ with 28 cases, 8∼11 weeks $30.38\%$ with 24 cases, so the treatment period was mainly these two periods with 52 cases($65.82\%$). 9. The average frequency of acupuncture treatment per week was mainly 2.1∼3.0 times with 45 cases($56.96\%$). In this case, men was 24 cases($53.33\%$) and women 21 cases($46.67\%$), so men was more than women. 10. The frequency of herbal prescription was mainly Gamijungjitang and Gamijingjibogansan with 76 cases($85.39\%$).

• Journal of Korean Ophthalmic Optics Society
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• v.16 no.4
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• pp.409-415
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• 2011

Purpose: To design applied anamorphic lens that focal length ratio is 3:1 optical system to improve detecting distance. Methods: We defined a boundary condition as $50^{\circ}{\sim}60^{\circ}$ for viewing angle, horizontal direction 36mm, vertical direction 12 mm for focal length, f-number 4, $15{\mu}m{\times}15{\mu}m$ for pixel size and limit resolution 25% in 33l p/mm. Si, ZnS and ZnSe as a materials were used and 4.8 ${\mu}m$, 4.2 ${\mu}m$, 3.7 ${\mu}m$ as a wavelength were set. optical performance with detection distance, narcissus and athermalization in designed camera were analyzed. Results: F-number 4, y direction 12 mm and x direction 36 mm for focal length of the thermal optical system were satisfied. Total length of the system was 76 mm so that an overall volume of the system was reduced. Astigmatism and spherical aberration was within ${\pm}$0.10 which was less than 2 pixel size. Distortion was within 10% so there was no matter to use as a thermal optical camera. MTF performance for the system was over 25% from 33l p/mm to full field so it was satisfied with the boundary condition. Designed optical system was able to detect up to 2.9 km and reduce a diffused image by decreasing a narcissus value from all surfaces except the 4th surface. From sensitivity analysis, MTF resolution was increased on changing temperature with the 5th lens which was assumed as compensation. Conclusions: Designed optical system which used anamorphic lens was satisfied with boundary condition. an increasing resolution with temperature, longer detecting distance and decreasing of narcissus were verified.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.2
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• pp.211-221
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• 2004

The purpose of this study is to evaluate the distribution and change of curvature of the anterior corneal surface with age in emmetropia. 504 subjects who have emmetroia with good naked vision of at least 0.6-1.0 (spherical equivalent: +0.75D- -0.75D) participated in this study. The 504 subjects into 8 groups with 10 year interval from 3-year to 83-year, and their corneal curvatures were analyzed using manual keratometry. The results are as follows. In individual analysis: First, regression analysis of corneal curvature radius with age has given an equation: Y = -0.003x + 7.796 (r = -0.26). The average corneal curvature radii was measured to be $7.68{\pm}0.25mm$ at 38.3-year and range was 6.98-8.54 mm. Second, frequency of corneal curvature radius were obtained in 36% between 7.61 and 7.80 mm, 78% between 7.41 and 8.00 mm, 96% between 7.21 and 8.20 mm, 100% between 6.98 and 8.54 mm. Third, as for the comparison of corneal curvature radius with respect to sex, The mean value of male (n = 304, mean: 37.6-year $7.72{\pm}0.24mm$, Range: 7.09-8.54 mm) is larger than that of female (n = 200, mean: 39.3-year $7.62{\pm}0.24mm$, Range: 6.98-8.42 mm) by 0.1mm (p<0.01). In groups analysis: First, regression analysis of corneal curvature radius with age has given an equation: $Y=-0.0066x^2+0.0227x+7.7282$ (r = -0.90). Second, vertical and horizontal curvature radius decreased with age (p < 0.01). Especially the decrease of horizontal curvature radius were more pronounced than the decrease of vertical (horizontal:10-70 age group: 0.38 mm decrease, vertical:10-70 age group: 0.20 mm decrease). Third, difference between steep and flat meridian (astigmatism) progressively decreased with age. (low age group:0.18 mm difference, high age group: 0.08 mm difference). Fourth, the corneal curvature radius of male was larger than female's in total groups(p < 0.01). Consequently, the change of corneal curvature radius with age progressively decreased in all conditions (mean, vertical, horizontal, male, and female) and this change was more outstanding in horizontal rather than in vertical.