• Journal of Korean Ophthalmic Optics Society
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• v.19 no.3
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• pp.353-362
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• 2014

Purpose: The present study was aimed to investigate the change of higher-order aberrations induced by aging and the effect of myopic degree on the correlation between age and higher-order aberrations. Methods: The higher-order aberrations in 931 eyes aged from 20 to 60 were measured by using a LADARWave device employing Hartmann-Shack system to analyze the effect of myopic degree measured by manifest refraction test on higher-order aberrations. Results: Coma and vertical coma aberrations were significantly decreased by the increase of myopic degree while vertical astigmatic aberration was significantly increased. The correlations of age and coma, vertical coma, spherical, vertical trefoil, horizontal trefoil, vertical astigmatic, horizontal astigmatic and vertical tetrafoil aberrations depended on the myopic degree, except for horizontal coma and horizontal tetrafoil aberrations. Conclusions: It is suggested to consider the myopic degree for the refractive correction including the laser surgery based on the present result that higher-order aberrations are affected by the myopic degree.

• 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 the Korea Academia-Industrial cooperation Society
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• v.15 no.9
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• pp.5621-5627
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• 2014

To specify the standard of LASEK surgery, this study examined the determination factors affecting the high order aberrations (HOAs) in preoperative and postoperative LASEK. 51 adult patients (102 eyes) were evaluated at the baseline and 2 months after LASEK surgery from Nov 2011 to Jul 2012. The postoperative HOAs ($0.538{\mu}m$) were higher than the preoperative ($0.341{\mu}m$). In linear regression analysis, the refractive components that affected the postoperative HOAs were $J_0$ of corneal astigmatism (CA, 0.400), $J_0$ of refractive astigmatism (RA, 0.389), corneal astigmatism (CA, 0.282), spherical equivalent (SE, 0.239), refractive astigmatism (RA, 0.213), and pupil size (PS, 0.194) with a high R. In multiple regression, $J_0$ of CA, PS and SE were significant factors with the postoperative HOAs. In conclusion, both HOAs and $J_0$ of CA should be considered when determining the suitable factors for LASEK surgery.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.4
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• pp.365-372
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• 2012

Purpose: To investigate ocular higher order aberrations (HOA) and spherical aberration changes caused by an aspheric soft contact lens designed to reduce spherical aberration (SA) of the eye. Methods: Fifty subjects who have successfully experienced soft contact lenses were refitted with aspheric design (Soflens Daily Disposable: SDD, Bausch+Lomb) soft contact lens. Ocular higher order aberrations (HOA) and stand alone SA were measured and analyzed for a 4-mm pupil size using Wave-Scan Wavefront$^{TM}$ aberrometer (VISX, Santa Clara, CA, USA). High and low contrast log MAR visual acuity and contrast sensitivity function (CSF) were also measured under photopic and mesopic conditions (OPTEC 6500 Vision Tester$^{(R)}$). All measurements were conducted monocularly with an undilated pupil. Results: The RMS mean values for total HOA with SDD contact lenses were significantly lower than those at with unaided eyes (p<0.001) and a reduction for SA in the SDD was close to the baseline SA (zero ${\mu}m$) (p<0.001). For the SDD lens, there was a statistically significant correlation between the changes in the total HOA and the contact lens power (r=0.237, p=0.018) as well as between the changes in SA and the lens power (r=0.324, p=0.001). High contrast visual acuity (HCVA) and low contrast visual acuity (LCVA) with SDD lenses were $-0.063{\pm}0.062$ and $0.119{\pm}0.060$, respectively under photopic and $-0.003{\pm}0.063$ and $0.198{\pm}0.067$, respectively under mesopic condition. Contrast Sensitivity Function (CSF) with SDD lenses under both photopic and mesopic conditions was $3.095{\pm}0.068$ and $3.087{\pm}0.074$, respectively. Conclusions: The SDD contact lens designed to control SA reduced the total ocular HOA and SA of the eye, resulting in compensating for positive SA of the eyes. Thus, the optical benefits of the lens with SA control would be adopted for improving the quality of vision.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.2
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• pp.179-186
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• 2013

Purpose: To compare corneal asphericity, visual acuity (VA), and ocular and corneal higher-order aberrations (HOAs) between myopic refractive surgery and emmetropia groups. Methods: Twenty three subjects ($23.0{\pm}2.5$ years) who underwent myopic refractive surgery and twenty emmetropia ($21.0{\pm}206$ years) were enrolled. The subjects'criteria were best unaided monocular VA of 20/20 or better in both two groups. High and low contrast log MAR visual acuities were measured under photopic and mesopic conditions. Corneal and ocular HOAs were measured using Wavefront Analyzer (KR-1W, Topcon) for 4 mm and 6 mm pupils. Corneal asphericity was taken by topography in KR-1W. Results: There was no significant difference in VA between two groups under either photopic or mesopic conditions. In ocular aberrations, there were significant differences in total HOAs, fourthorder and spherical aberration (SA) for a 6 mm between two groups (p=0.045, p<0.001, and p<0.001, respectively). In corneal aberrations, there was a significant difference in SA for 4 mm (p=0.001) and 6 mm (p<0.001) pupils between two groups and there were statistically significant differences in total HOAs (p<0.001) and fourth-order aberrations (p<0.001) between two groups for a 6 mm pupil. There was a significant correlation in emmetropia between Q-value and SA in ocular aberrations for 4 mm and 6 mm pupils (r=0.442, p=0.004, and r=0.519, p<0.001) and in corneal aberrations for 4 mm and 6 mm pupils (r=0.358, p=0.023, and r=0.646, p<0.001). No significant correlations were found between Q-value and SA in refractive surgery group. Conclusions: VA in myopic refractive surgery is better than or similar to emmetropia. Nevertheless, the more increasing pupil size is, the more increasing aberrations are. Thus, it could have an influence on the quality of vision at night.

• 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)

• The Korean Journal of Vision Science
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• v.20 no.4
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• pp.469-482
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• 2018

Purpose : We investigated the change of spherical and comma aberrations after wearing aspheric soft contact lens (ASCL) in young myopes. Methods : Fifty young myopes ($23.15{\pm}1.70years$, spherical equivalent: $-2.90{\pm}1.75D$) were recruited and refractive errors were corrected using ASCL (Biotrue, Bausch+Lomb, USA). High order aberrations were measured in the 4 mm pupil size using the wavefront analyze and pupil sizes were measured with a pupillometer at the modes of scotopic condition (light off) at 3.5 m in the 100 lx illuminance condition. Results : Spherical aberrations and coma aberration of the 20s myopes were $0.026{\pm}0.031{\mu}m$ and $0.078{\pm}0.039{\mu}m$ respectively, and $0.019{\pm}0.026{\mu}m$ and $0.082{\pm}0.038{\mu}m$ after ASCL wear that spherical aberration was decreased and coma aberration was increased. However, spherical aberration was decreased in the 68% of the subject have positive spherical aberration, and increased in the 11% of the subject have negative spherical aberration. Coma aberration was increased in the 53% of the subject, did not change in the 19% of the subjects, and decreased in the 28% of the subject. Spherical aberration was not different with the refractive errors in low and moderate myopies, however, coma aberrations was higher in the higher myopes. Conclusion : In a scotopic condition without accommodation stimuli, spherical aberration is decreased after wearing ASCL, however in the subject have negative spherical aberration spherical aberration could be increased, and which is thought to be the influence of contact lens design and pupil size.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.1
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• pp.111-120
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• 2014

Purpose: This study was to investigate changes in the thickness of cornea, curvature of cornea, and aberration depending on the water contents, materials, and refractive power of contact lens. Methods: The differences in the corneal thickness between pre- and post-wearing the lenses were compared using 5 kinds of lenses. The changes in the corneal thickness, the curvatures of the anterior and posterior cornea, and high order aberration (HOA) before and after wearing the lenses were investigated at the center of the cornea, and the different distance and the direction away from the center of the cornea. For the equipments of measurement, ORB ScanII (Bausch & Lomb Inc, ver 3.14) was used to measure the corneal topography and thickness, and Zywave (Bausch & Lomb Inc, ver 5.20) was used to analyze the high order aberration. Results: Five (S1, S2, S3, T1, T2) of the lens was used for this study, excluding the lens T2 lens has four lenses and the thickness of the corneal shape, but the impact is minimal. In the case of the hydrogel soft contact lenses (T2 lens) with low oxygen permeability, the corneal thickness showed distinct increasing patterns. The high order aberration and coma aberration were most changed in the silicon hydrogel toric lens, while the depth of anterior was most changed in the hydrogel toric lens. Conclusion: Among the 5 kinds of contact lenses with different water contents, materials, and refractive power used for this study, the corneal shape change was small for the lenses with an oxygen permeability (Dk) of more than 28, and the largest for the lenses with a very low oxygen permeability.

• Journal of Korean Clinical Health Science
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• v.3 no.2
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• pp.372-377
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• 2015

Purpose: The aim of this study is to compare total high order aberrations between surgery which uses TransPRK and general laser assisted sub-epithelial keratomileusis. Methods: The patients who had general laser assisted sub-epithelial and TransPRK laser assisted sub-epithelial by visiting ophthalmic clinic in Ulsan from January 2014 to August 2014 was researched. Results: When comparing total high order aberrations before and after operation, it was found that total high order aberration in general laser assisted sub-epithelial group increased to $0.222{\pm}0.078{\mu}m$ from $0.074{\pm}0.019{\mu}m$ while that in TransPRK assisted sub-epithelial group increased to $0.179{\pm}0.045{\mu}m$ from $0.076{\pm}0.032{\mu}m$. When comparing the increment in total high order aberrations between two groups after surgery, it was found that the increments of TransPRK assisted sub-epithelial group were statistically smaller than that of general laser assisted sub-epithelial group (p<0.05). Conclusions: This study made a comparative analysis of total high order aberrations between general laser assisted sub-epithelial and TransPRK assisted sub-epithelial which was introduced recently and the result showed a significant difference. The findings of this study suggest that TransPRK assisted sub-epithelial can be used widely in simply improving eye sight and quality of vision by reducing an increase in high order aberration caused by orthokeratology surgery. It is expected that TransPRK assisted sub-epithelial will be helpful for improving the understanding quality of eye sight which occurs by several methods of vision correction surgery.

• Journal of Korean Clinical Health Science
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• v.7 no.1
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• pp.1232-1237
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• 2019

Purpose. In this study, two types of soft contact lenses with different materials were selected to compare the time of tear film destruction and high order aberrations before and after wearing. Methods. Thirty patients (60 eyes) in their 20s were included in this study. Two lenses with different materials, Group 4 (Etafilcon A) and Group 5 (Narafilcon A) were selected. Using aberration analyzer and keratometry, high-order aberration and tear film test (NIF-BUT, NIAvg-BUT) were performed before and after wearing. Results. When comparing the higher aberrations of the Etafilcon A and Narafilcon A lenses, the higher aberrations of the Narafilcon A lens were higher overall. For the initial tear film break-up time (NIF-BUT) after wearing, the Etafilcon A lens was reduced by 4.0 seconds and the Narafilcon A lens increased by 0.6 seconds. For the mean tear film break-up time (NIAvg-BUT) after wearing, the Etafilcon A lens decreased by 2.4 seconds and the Narafilcon A lens increased by 1.7 seconds. Conclusions. NIF-BUT and NIAvg-BUT of Narafilcon A lens were increased. The lens with relatively low water content and higher oxygen permeability than the lens with high water content has relatively less tear evaporation, which means that the time of destruction of the tear film is increased.