• Journal of Korean Clinical Health Science
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• v.10 no.2
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• pp.1587-1593
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• 2022

Purpose. This study was to investigate the degree of refractive error that occurs depending on the measurement location of the subject when performing a refraction test using the automatic refractor. Methods. When performing the auto-refraction test, measurements were taken while increasing the distance between the forehead and the forehead rest, and the measurements were made by tilting the head clockwise and counterclockwise. Results. During the auto-refraction test, significant refractive error occurred when the forehead was not attached to the forehead support or the subject's head was turned clockwise or counterclockwise. Conclusions. When performing a refraction test using an automatic refractor, the examiner will have to pay attention to whether the subject's forehead is in close contact with the forehead rest, and whether the head is tilted.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.3
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• pp.7-12
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• 2008

Purpose: To evaluate ultraviolet (UV) blocking characteristics of transparent and tinted ophthalmic lenses. Methods: The transmittance spectra of ophthalmic lenses were measured using the method suggested in ANSI Z80.1 standard. Transmittance percentage were calculated for each lens for UV (200~380 nm; UVA, UVB, UVC) and blue light portions (380~400 nm) of spectrum. Results: The results indicate that transparent plastic lenses with middle, high refractive index and tinted plastic lenses had superior UV blocking characteristics at UV radiation while UV blocker-untreated lenses such as crown glasses and CR39 did not. All except high refractive index lenses and anti-glare night vision lens was not effectively blocked blue light. Conclusions: Crown glass and CR39 lenses need to treat UV blockers to protect eyes from UV. Also, all lenes except high refractive index lenses and anti-glare night vision lens need to treat blue light blockers for protecting from blue light.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.2
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• pp.361-370
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• 2004

The purpose of this study was to evaluate the outcome and Factors that influence the quantity of Phoria in the low correction and perfect correction. Also the coincidence with the opticenter and the pupillary distance was a principal factor that influence the quantity of Phoria. Thereupon, this study is attributed to promote the perfect Phoria test. The subjects for this study were 120 persons(240 eye) in myopic refractive errors. ISP/WIN program was used for the data analysis. The collected data was analyzed by descriptive statistics and Spearman's correlation coefficient. The results of this study were as follows: 1. The prism pattern was difference between low correction and perfect correction in the Phoria test. The proportion of orthophoria was changed from 10.0% to 12.5%, exophoria was changed from 67.5% to 62.5%, and esophoria was changed from 22.0% to 32.5%, respectively. 2. The average of optical center distance and pupillary distance were 31.70mm and 31.49 mm, respectively. 3. Among the 120 myopic glasses wearers, the distance between optical centers was coincided with the pupillary distance in 37.5%, and discrepant in 62.5%. 4. For the patients who were coincided with the pupillary distance, the proportion of exophoria decreased 53.33%, esophoria increased 20.0%. 5. For the changing of the quantity of Phoria in the low correction, the degree of exophoria decreased 1.11 prism diopters in the perfect correction, esophoria increased 0.39 prism diopters.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.1
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• pp.109-114
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• 2009

Purpose: This study was designed to investigate the condition of refractive correction on wearing glasses currently of elementary school children and their accommodative ability in Jinju city. Methods: Objective refraction, subjective refraction, amplitude of accommodation, negative and positive accommodation, accommodative facility, and dynamic retinoscopy were examined on 60 elemenary school children who aged 8~12 wearing myopiacorrected glasses. Results: The condition of refractive corrections was distributed that a case of full correction was 11.7%, a case of low correction with more than 0.8 visual acuity (VA) was 10%, and a case of low correction with less than 0.8 VA was 78.3% in wearing glasses currently. In results from examination of accommodative ability, the number of children having accommodative anomaly is 8 persons (13.3%), they were divided into accommodation insufficiency (4 persons), accommodative facility insufficiency (2 persons), accommodation excess (1 person), and accommodation insufficiency related to ocular function (1 person). Conclusions: It is demanded a periodic inspection of refractive correction to growing children, and the refractive correction after due consideration to accommodative ability is really needed.

• Journal of Korean Ophthalmic Optics Society
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• v.1 no.1
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• pp.65-72
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• 1996

The general property of plastic ophthalmic lens has been reviewed by the optical property and polymer structure. A PMMA which is synthesized by the polymerization of monomers of two or more kinds is termed a copolymer, and the main chain composes a skeleton of molecular structure in the polymer. Refraction index of polymer was governed mainly by the polarization of molecular and was followed to increase it conspicuously as Cl, Br, and Iodine was substitude to hydrogen. Thermal dependence of refraction index of polymer show that the higher distinctive characteristic than glass material.

• Journal of Korean Ophthalmic Optics Society
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• v.8 no.2
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• pp.53-56
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• 2003

After we compared the corrected len3 and the dominant eye who were wearing eyeglasses, elementary school in Iksan, we could get conclusions like these. 51 persons of the whole number, 65.4%, have the dominant eye of right. The refractive correlation to the spherical lens and astigmatic lens are the high non-dominant eye.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.3
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• pp.105-110
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• 2007

To investigate the ametropia and refractive error of 222 ametropic eyes of the 111 high school students in Gwangju Metropolitan City, the visual acuity test was performed by the object and subject method. 85% of the eye types were positive for myopia, 14% for emmetropia, and 1% for hyperopia, respectively. 38% of the abnormal refraction eyes were positive for simple myopia, 4% for myopia simple astigmatism, 56% for myopia compound astigmatism, and 0% for simple hyperopia, 0% for hyperopia simple astigmatism, 2% for hyperopia compound astigmatism, 0% for mixed astigmatism, respectively. 92% of the axes fo astigmatism were for astigmatism with-the-rule, 6% for astigmatism against-the rule, 2% for astigmatism oblique, respectively. As for the astigmatic power, 0.50 < cylinder < 1.00D was 68%, 1.00 < cylinder < 2.00D was 25%, and anything over the 2.00 cylinder D was 7%. As for the equivalent spheric power of myopic abnormal refraction eyes, -0.50 < spheric equivalent < -2.00D was 26%, -2.00D < spheric equivalent < -6.00D was 55% and anything over the -6.00D was 19%. The rate of wearing glasses was 74%. It increases compared to 20 years ago. 91% of the eye test place was the optical shop, 9% the eye doctor hospital. 80% of the students need to change their optical lenses because spherical equivalent power was over 0.50D.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.2
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• pp.345-352
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• 2004

We investigated the effect of age at initial correction, of 44 refractive amblyopic patients duration of correction on corrected visual acuity with the lapse of time for mean 33months(3months-59months). Full cycloplegic corrections were prescribed at the initial visit to all subjects. The distribution of initial corrected visual acuity was 0.02 to 0.5. Age at initial correction varied from 3 years to 12 years. The refractive error appeared to have the greatest influence on the visual outcome, showing continuous visual improvement after initial correction. But the age at initial correction did not appear to influence on the initial and final corrected visual acuity showed a significant difference, irrespective of age at the initial correction Or degree of anisometropia.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.2
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• pp.105-115
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• 2015

Purpose: The accuracy for measuring the refractive power of hydrogel contact lenses by spectacle lens holder and contact lens holder was evaluated. The accuracy for each sample was also analyzed with water content and diopter categories. Methods: The hydrogel contact lenses used for measurement were classified into three categories in water content (38%, 43%, 58%). Also, three diopter categories of refractive power were used such as -3.000 D, -7.000 D, -10.000 D. And also, the reliability of measurement results were evaluated by measuring refractive power with spectacle lens holder and contact lens holder using an Manual lensmeter. Results: In case of spectacle lens holder method, the average value of refractive power was -3.3273D for -3.0000 D, -7.1306 D for -7.0000 D and -10.2944 D for -10.0000 D, respectively. In case of contact lens holder method, the average value of refractive power was -3.1060 D for -3.0000 D, -7.0028 D for -7.0000 D and -10.2611 D for -10.0000 D, respectively. In measurement of all diopters, the accuracy of contact lens holder method was better than spectacle lens holder method. Conclusions: From these results, it is judged that the refractive power of soft contact lens by manual lensmeter with contact lens holder have a higher accuracy than spectacle lens holder.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.482-487
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• 2016

Ultra-violet rays are very harmful to eye health care. The blocking of ultra-violet rays and a reduction of optical reflection in the visible light range, which is to increase the share of transmitted light, and avoid the formation of ghost images in imaging, are important for the applications of polymer eyeglasses lenses. In this study, the high-refractive index polymer lenses, n=1.67, were fabricated by injection-molded method with the xylene diisocyanate monomer, 2,3-bis-1-propanethiol monomer, and benzotriazol UV absorber (SEESORB 709) mixture. To reduce the reflection of the polymer lens surfaces, multi-layer anti-reflection (AR) coatings were coated for both sides of the polymer lens using an E-beam evaporation system. The optical properties of the UV blocking polymer lens were characterized using a UV-visible spectrometer. The material properties of the thin films, which were composed AR coating layers, refractive index, and surface roughness, were analyzed by ellipsometry and atomic force microscopy. As a result, the fabricated polymer lens perfectly blocked ultra-violet rays below 395 nm with a blocking rate greater than 99%.