• Journal of Korean Ophthalmic Optics Society
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• v.12 no.3
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• pp.137-142
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• 2007

The purpose of this study was to investigate sole effect of therapy of spectacles correction on the refractive amblyopia. Spectacles were prescribed to give the same effect as the occlusion therapy undercorrecting in the case of hyperopia, and effectiveness of the therapy was compared with occlusion therapy without additional prescription. The results can be summarized as follows: 1. The higher anisometropic power was the lower initial visual acuity was. 2. Anisometropic power did not influence final visual acuity. 3. The latter beginning time of therapy was the higher astigmatism was. 4. Therapy of spectacles correction on the hyperopic amblyopia was quite effective.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.3
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• pp.281-286
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• 2010

Purpose: This research provided basic data for refraction by comparing the corrected diopter of trial lens and phoropter. Methods: We compared the corrected diopter of trial lens and phoropter, and analyzed statistical significance and relations of the spherical lens corrected diopter and cylindrical lens corrected diopter according to the types (trial lens and phoropter) of subjective refractive instruments. Also we analyzed statistical significance and relations between cylindrical lens corrected diopter at the astigmatism and the types (trial lens and phoropter) of subjective refractory instruments. Results: When we measured the corrected diopter of simple myopia, the mean value for corrected diopter was S-2.74D using the trial lens and S-2.65D using the phoropter. So the corrected diopter was 0.09D smaller when measured by phoropter. The degree of astigmatism was measured C-0.81D using the trial lens and C-0.77D using the phoropter which showed that the measured value was 0.04D smaller using the phoropter. On correlation analysis between the refractive instruments (trial lens and phoropter) and the corrected diopter, there was significant (p<0.01) strong correlation between refractory machine and corrected spherical diopter (r=0.996) and the correlation between refractory machine and corrected cylindrical diopter was r=0.986 and was also significant (p<0.01). Conclusions: The use of phoropter than trial lens was more desirable when performing refraction on high myopia (simple refractive error, high astigmatism), and when using trial lens, you should consider the vertex distance and the gap between overlapped lenses before prescription.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.1
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• pp.17-22
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• 2014

Purpose: We aimed to evaluate reliability of eye exam for visual acuity as a function of distance. Methods: There were 39 patients (78 eyes) who had visual acuity 1.0 or more at 5 meters. We measured refractive power of patients at each distances, 5 meters, 4 meters and 3 meters. Automatic chart (LCD-700, Hyeseong Optic. Co., Korea) used for visual acuity, skiascope (Beta 200, Heine, Germany) and auto refractometer (RK-5, Canon, Japan) used as for objective refraction. Accommodation was examined by minus lens addition methods, and Accommodative lag was examined by grid chart for reading distance. Results: Being compared to 3 meter test, Amount of corrected spherical refractive power decreased by $0.10{\pm}0.38$ D, astigmatism decreased by $0.05{\pm}0.10$ D, and axis of astigmatism rotated toward to temporal by $2.64{\pm}18.75$ degrees for right eyes, by $11.43{\pm}48.55$ degrees for left eyes in case of 5 meter test. Changes of corrected refraction and astigmatism were slightly correlated (r=-0.31, r=-0.29). Conclusions: Because corrected refraction power and amount of astigmatism decreased and axis of astigmatism tends to turn the temporal direction according to exam distance, examination distance of visual acuity should improved as to 5 meters.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.3
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• pp.349-354
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• 2015

Purpose: To investigate the changes of corrective values of astigmatism caused by the position of circle of least confusion on retina in refining astigmatic test using cross cylinder. Methods: 62 subjects (115 eyes) aged $22.24{\pm}2.48$ years participated for this study. After astigmatic test using a radial chart, refining test was performed using a cross cylinder in a condition of maximum plus to maximum visual acuity (MPMVA). Astigmatic refining test was repeatedly performed in each condition of which S+0.75 D, S+0.50 D, S+0.25 D, S-0.25 D, S-0.50 D, and S-0.75 D are added to spherical lenses of MPMVA. The measured values were compared with the values in MPMVA condition. Results: As compared with values in condition of MPMVA, change of astigmatic axis was increased with add the power of (+) spherical lenses and (-) spherical lenses. In same spherical condition, change of astigmatic axis was decreased with increment of astigmatic power (p<0.05). The corrective power of astigmatism was reduced with increment of (+) spherical lenses (p<0.05), and was raised with increment of (-) spherical lenses compared with the power in MPMVA condition. In case of adding (+) spherical lenses, difference of astigmatic power increased with increment of corrective astigmatism power in same test condition. Conclusions: In order to obtain a proper values for corrective astigmatism, position of circle of least confusion should be accurately adjusted before the performing an astigmatism's refining test.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.2
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• pp.231-237
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• 2014

Purpose: This study is research of the conditions which causes difference between the refractive power of the measurement of autorefractometer and the prescription using phoropter. Methods: Autorefractometer (SR-7000) and phoroptor (AV-9000) were used to measure 60 eyes of 30 participants who had no eye diseases and wore the corrective lens due to Ametropia. To prevent the dependence of the prescription value of the refractive power on the testers, two testers measured the refractive power of the eyes of the participants at the same measuring conditions. Results: Statistically, the prescribed values of the refractive power by two testers were not significantly different. Most of the prescribed values of the refractive power were smaller than the refractive power by autorefractometer In case of myopic eyes, the difference between refractive powers by the measurement of autorefractometer and the prescription using phoropter showed the trend of increase as the spherical refractive power became larger. The result was analyzed by the range of the different cylindrical refractive power for the myopic astigmatic eyes. In this case, the difference between refractive powers showed the trend of decrease as the cylindrical refractive power became larger. Conclusions: No difference between the prescribed value by two testers was observed. In case of myopic or myopic astigmatic eyes, the difference between refractive powers by autorefractometer and the prescription were measured to be approximately proportional to the refractive powers of ametropic eyes. As the this difference become larger for the participant who needs the lens of larger refractive power, additional caution is needed in the prescription of the refractive power of the corrective lens.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.3
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• pp.271-277
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• 2013

Purpose: The purpose was to study the corneal refractive power changes associated with the wearing of everted silicone hydrogel soft lenses. Methods: The corneal refractive power and corneal astigmatism were measured using corneal topographer (CT-1000, Shin-nippon Co., Japan) for checking change of corneal refractive power and objective refractive error was measured by auto-refractometer (Natural vision-K 5001, Shin-nippon Co., Japan). We measured at baseline and 1 week after lens wearing. Results: The correcting of corneal refractive power could be effective in low myopia. It's more effective to the higher power of greatest meridian of cornea and the more corneal astigmatism. 73% of subjects' refractive error was decrease less than 1 D and 17% of the subjects had an reverse effect (increase) occurs. The reduction of objective refractive error was more effective when cornea refractive power was great or corneal astigmatism was much. Conclusions: Pressure which the everted silicone hydrogel lens to the cornea could be caused. It occurred as the degrees of corneal power, corneal astigmatism and objective refractive error differences. Selection of an appropriate subject is important considering difficulty of changing the parameters of the lens.

• Journal of Korean Ophthalmic Optics Society
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• v.4 no.2
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• pp.17-22
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• 1999

In this study, corneal power and eye refraction error were studied on myopic of unaccommodated koreans. The mean of refraction error power is -2.39D(male : -2.75D, female : -2.02D). The mean of corneal refraction error power is +43.90D(male : +44.07D, female : +43.71D). It is +0.90D higher than that of the model eye by Gullstrand(about + 43.00D).

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.126-127
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• 2003

눈의 시력을 진단하는 도구로는 시력표, 검영기, 빔프로젝터, 자동굴절력측정기 등이 있다. 파면분석기(wavefront aberrometer)를 이용하면 눈의 굴절력 및 난시도수 외에도 광학적 고위수차(higher order aberration)를 표현하는 파면수차함수를 산출할 수 있기 때문에, 눈의 결상 능력을 정확하고 정밀하게 진단할 수 있는 가능성을 가지고 있다. 따라서 파면분석기는 현재까지 사용되고 있던 시력 또는 굴절력 계측기들의 다음 세대를 이어갈 것으로 전망하고 있다. (중략)

• 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.18 no.2
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• pp.165-171
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• 2013

Purpose: This study are to analyze and to compare between pupillary size, reaction time, refractive error, corrected vision, dominant eye, static visual angle (SVA) and kinetic visual acuity (KVA) of male and female college students, to measure KVA of them in full correction and to identify changes of KVA by +0.50 D and -0.50 D spherical power addition respectively in full correction condition. Methods: KVA, SVA, pupillary size, reaction time, refractive error, corrected vision and dominant eye of 40 male and 40 female optical science students were measured by utilizing KOWA AS-4A, reaction time measurement program, subjective refractometer, and objective refractometer, and KVAs were measured when +0.50 D/-0.50 D were added in both eyes respectively. Results: Binocular KVA of whole subjects was $0.45{\pm}0.22$, and in monocular KVAs were $0.36{\pm}0.19$ for right eye and $0.34{\pm}0.19$ for left eye, and binocular KVA was significantly higher than monocular KVA. It appeared that the better SVA was, the better KVA was in significant way, and in terms of refractive error the less myopia amount was, the better KVA was, but it was not significant statistically. The lower astigmatism was, the slightly and significantly higher KVA was when dividing between equal or less than -1.00 D astigmatism group and over -1.00 D astigmatism group. In resulting from correction condition of refractive error KVAs were $0.45{\pm}0.22$ for full correction, $0.26{\pm}0.15$ for +0.50 D addition, $0.48{\pm}0.22$ for -0.50 D addition which indicates that KVA in over myopia correction was significantly the highest and followed by full correction and under correction. Similar findings were revealed in both male and female, and KVA of male was better than female in comparing between male and female. There was no significantly different KVA between dominant eye and non-dominant eye. Conclusions: Accordingly, it is concluded that KVA is related with far distance SVA, astigmatism amount, and refractive error amount except a dominant eye. Through this research, it was found that prescription for enhancing KVA is to make full correction or to overcorrect slightly myopia.