• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.78-79
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• 2002

눈의 시력을 진단하는 도구 또는 장비로는 자각식 측정법인 시력표, 타각식 계측기로는 검영기와 자동굴절력측정기 등이 있다. 이들 방법으로 얻는 결과는 시력 또는 굴절력 값으로 제한된다. 그러나 인체안도 일반 광학계와 같이 공간적으로 불균일한 광학적 특성을 가지기 때문에, 눈의 광학적 기능을 정확하게 진단하기 위해서는 공간에 따른 광학수차 분포를 측정할 필요가 있다. 특히 엑시머레이저를 이용한 굴절각막교정수술에서, 광학수차 정보는 정교한 교정수술을 위한 기초 자료가 될 수 있다. (중략)

• 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.

• Journal of Korean Ophthalmic Optics Society
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• v.2 no.1
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• pp.149-154
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• 1997

We investigated the dominant eye of 123 Korean over twenty years old, then examined the refractive correlation of dominant eye, the unaided visual acuity and over-correlation. The results of these investigations are following. 91 persons of the whole number, 74%, have the dominant eye of right. The refractive correlation to the glasses are the high dominant eye. There are many men who are the same in unaided visual acuity. In men, they prefer to have the non-dominant eye but in women, they like better to have the dominant eye. The unaided visual acuity of ametropia, however, prefer to have the non-dominant eye in both men and women. In case of over-correction of an eye, there was affected the response of the other eye over 50% at the same time and the case of over-correction of dominant eye has more number than that of non-dominant eye.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.3
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• pp.7-15
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• 2009

Purpose: To investigate the corneal recovery after discontinuing orthokeratology (OK) lenses wear in children for long-term period. Methods: Among the OK lens wearers who wear over 8 months and showed successful refractive correction, 25 subjects were selected who want to discontinue the OK lenses. Uncorrected visual acuity, refractive correction, corneal curvature (Sim K), central corneal thickness and corneal eccentricity were measured during the OK lens wearing period and after discontinuation for 1 month. Results: Uncorrected visual acuity and corneal shape had remodeled significantly during the OK lens wear and recovered significantly during the first week of discontinuation. Uncorrected visual acuity and refractive correction had achieved full recovery 2 weeks after discontinuation of lens wear and were highly correlated with the changes in corneal thickness. But corneal shape recovered slowly, eccentricity had recovered fully after 1 month and corneal curvature and central thickness had not been achieved full recovery until 1 month after discontinuation. Conclusions: Recovery of after longterm use of OK lens is rapid for refractive change, but slow for corneal curvature and central thickness that to refit the contact lenses, practitioners need patience.

• 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.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.13 no.4
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• pp.65-73
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• 2008

Purpose: The purpose of this study is to investigate the effect of age in the response to long-term overnight orthokeratology (OK) lens wearing. Methods: Among volunteers, ninety-five healthy subjects who had no eye diseases and could wear OK contact lens at least for 8 hours every day were divided into three groups children, youngsters and young adults. Unaided logMAR visual acuity, refractive error, apical corneal radius, corneal asphericity and central corneal thickness were measured with different period; before and after one day, one week, two weeks, one month, three months and six months of OK lens wear. Paired student t-test, ANOVA analysis and Pearson correlation were used with a critical p value of 0.05 for statistical analysis. Results: All groups showed statistically significant (p<0.001) improvement in unaided visual acuity, a trend for flattening in the apical corneal radius, decrease in central corneal thickness and less prolate after OK lens wear. The child group showed significantly rapid change (p<0.001) in visual acuity, and apical corneal radius showed that they reached the targeted refractive change earlier compared with youngster and adult groups. The visual effect of OK lens was significantly related with the change in central corneal thickness after long-term OK lens wear, especially in child and youngster group, and central corneal thickness were highly correlated with the targeted refractive change. Conclusions: Visual acuity change is statistically correlated with the central corneal thickness change, which is highly correlated with targeted refractive change in the long-term orthokeratology and younger lens wearers showed a rapid response to OK lens wear, suggesting a reduced epithelial response with increasing age. The results found this study extends our understanding and development in the long-term orthokeratology.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.3
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• pp.383-387
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• 2014

Purpose: To investigate the effect of corneal unique shape to changes of refractive full corrections when pupil size changes. Methods: Subjective refraction for monocular full correction was performed to 30 subjects ($23.33{\pm}1.78$ of age, 60 eyes) in two room conditions, 760 lx and 2 lx, respectively. Pupillary diameter was measured in two conditions and the change pattern was analyzed using a peak data of corneal topography. Results: Pupillary diameter was 3.74~4.00 mm in 760 lx and 5.52~5.90 mm in 2 lx. By comparison with refractive data in 760 lx, those data in 2 lx was changed as follows: more (-) spherical power of 17 eyes (28.3%), more (+) spherical power of 10 eyes (17.7%), more (-) cylinderical power of 17 eyes (28.8%), less (-) cylinderical power of 9 eyes (15.3%), and astigmatic axis rotation of 36 eyes (62.1%). From peak data of corneal topography, the changing pattern of two principal meridians was classified into 4 types. Conclusions: Expansion of the corneal refractive surface accompanied with pupillary dilation may be a main factor that effects the changing a values of subjective refraction because of unique corneal shape. Therefore, subjective refraction should be performed under the nearest lighting condition to a main living environment.

• Proceedings of the KAIS Fall Conference
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• 2010.05b
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• pp.890-893
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• 2010

알코올 섭취 후 발생하는 해부생리학적 변화가 눈의 일시적인 근시화에 미치는 영향을 알아보고자 하였다. 평균 24.5${\pm}$1.5세의 남자 8명(16 안)을 대상으로 0.42 g/kg의 알코올을 30분 간에 걸쳐 섭취토록 한 다음, 알코올 섭취 1시간, 4시간, 24시간 후의 교정굴절력, 각막곡률반경과 두께, 동공직경, 안압, 그리고 안구축의 길이변화를 측정하여 알코올 섭취 전과 비교하였다. 알코올 섭취 1시간 후에 알코올 섭취 전과 비교하여 호흡 중 알코올 농도가 가장 높았고(p<0.001), 교정굴절력의 구면 (-)굴절력 증가(p<0.05), 동공 크기의 감소(p<0.05), 안압의 하강(p<0.001), 그리고 안구축의 길이 증가가 나타났다. 알코올 섭취 4시간 후에도 모든 측정값들이 섭취 1시간 후와 동일한 경향이었다. 그러나 알코올 섭취 24시간 후에는 알코올 섭취 전과 비교하여 의의있는 변화를 보이지 않았다. 알코올 섭취로 인한 일시적인 근시화는 안압하강과 안구축의 길이변화와 관련성이 있을 것으로 판단된다.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.1
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• pp.45-51
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• 2013

Purpose: This study was performed to provide indicator of expected aniseikonia by correcting refractive error and to investigate influential factors on aniseikonia. Methods: 20 college students (14 males, 6 females, a mean age of $22.50{\pm}2.72$ years) were selected as subjects whose refractive error with spherical equivalent were within ${\pm}0.50$ D, corrected visual acuity were more than 1.0, and aniseikonia values by AWAYA were less than 1%. After correcting refractive error with spectacles in anisometropia induced by wearing contact lens on their dominant eye or non-dominant eye, practical measured values of aniseikonia were compared with theoretical expected values of it by the formula of spectacle magnification. Results: Practical measured values were higher than theoretical expected values in induced aniseikonia over the whole range of diopter of wearing contact lens. And there was higher measured value of aniseikonia in case of higher diopter of wearing contact lens to induce anisometropia and correcting refractive error with spectacles of (+) diopter after wearing contact lens of (-) diopter to induced anisometropia in dominant eye of women. Conclusions: It is considered that dominant eye plays more important role for visual function in induced aniseikonia and factors such as the induced eye of aniseikonia, the diopter of wearing contact lens, and gender have influenced on aniseikonia.