• Title/Summary/Keyword: Oblique Astigmatism

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Analysis of Addition Power for New Wearer of Progressive Addition Lenses (누진렌즈 안경 처음 착용자의 가입도 분석)

  • Joo, Seok-Hee;Shim, Hyun-Suk;Shim, Jun-Beom
    • Journal of Korean Ophthalmic Optics Society
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    • v.18 no.3
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    • pp.247-251
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    • 2013
  • Purpose: To analyse the addition power of new wearer of progressive addition lenses. Methods: Data of 636 subjects who have been prescribed progressive addition lenses as the first time were used for analyse. The range of age for was between 41~78 years old and they visited the optical practice in Gwangju metropolitan city from 2001 to 2013Date of refractive state, gender and age were analysed. Results: The difference of addition by gender was 1.71 D in male and 1.67 D in women. The difference of addition by refractive error was 1.67 D in emmetropic patients and 1.74 D in myopic patients, 1.90 D in hyperopic patients. The difference of addition by age was1.26 D in 41~44 years old sge group, 1.48 D in 45~49 years old age group,1.72 D in 50~54 years old age group 1.84 D in 55~59 years old age group, 2.10 D in 60~64 years old age group and 2.43 D in over 65 years old age group. The difference of addition by diopter in myopic patients was 1.58 D in low myopic patients and 1.48 D in middle myopic patients, 1.67 D in high myopic patients. The difference of addition by axis of astigmatism was 1.80 D in with-the-rule astigmatism, 1.64 D in against-the-rule astigmatism and 1.65 D in oblique astigmatism. Conclusions: The Addition power of progressive lenses were different according to the types of refractive error, astigmatism axis and age.

The Study for Refractive Error of the Westerner in 20s: North America Region (20대 서양인의 굴절이상에 대한 연구: 북미지역)

  • Lee, Young-Il;Hong, Jin Seok
    • Journal of Korean Ophthalmic Optics Society
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    • v.14 no.1
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    • pp.97-101
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    • 2009
  • Purpose: To assess the refractive state of the westerners (male: 44, female: 62) in twenties who visited the A optical shop at Seoul. Methods: The visual acuity test was performed by the objective and subjective method. Results: The emmetropia and myoptia were 35 and 177 eyes (83.49%), respectively. About 26.76% of tested males was ametropia. Myopia compound and myopia simple astigmatism were found in 60.56% and 12.68% of tested males, respectively. However, about 43.40% of tested females was ametropia. Myopia compound and myopia simple astigmatism were 49.06% and 7.55% were found in tested females, respectively. As for the equivalent spheric power of myopic abnormal refractive eyes, the -0.5D < spheric equivalent ${\leq}$ -2.00D was 35.02% of tested westerners, the -2.00D < spheric equivalent ${\leq}$ -6.00D was 60.45% and anything over the -6.00D was 4.53%. The percentages of with-the-rule, against-the-rule and oblique astigmatism among people with astigmatism were 59.82%, 26.78% and 13.40%, respectively. The average of pupillary distance in male (63.5${\pm}$2.4 mm) was greater than that in female (59.7${\pm}$2.3 mm). Conclusions: Korean opticians were provided some useful information about making up a prescription for the westerners in twenties by this research.

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The Study of Abnormal Refraction Eye on Women Population of University Students in South-East Korea (한국 동남지역 여대생들의 굴절이상 눈에 대한 연구)

  • Choi, Hoe-Sung;Jung, Su-Ja;Kim, Douk-Hoon
    • Journal of Korean Ophthalmic Optics Society
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    • v.13 no.1
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    • pp.125-129
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    • 2008
  • Purpose: To research the study of abnormal refraction eye on women population of university students in South - East Korea. Methods: Between March 2007 and October 2007, the refraction test of eye glasses wearer was evaluated on women population (367 students, aged 19~22 years) of university in living on Kyung-Nam and Pusan province. Data was analysed with T-test. Results: On the abnormal refraction status, Compound Myopic Astigmatism was 76.72%, simple myopia was 10.90%, mixed astigmatism was 6.27%, respectively. On the prevalence of myopic power, low was 59.57%, moderate was 24.93%, high was 15.49%, respectively. On the myopic equivalent power, the right eye had more increase to compare to left eye. but these was not a statically significant correlation (p<0.5) between the right and left eyes. On the anisometropia of spherical equivalents and cylinder power, most subjects was under 1.0 diopter. On the other hand, the type of astigmatic axis was with-the rule (70.79%), against -the rule (18.41%), and oblique (10.80%). Conclusions: This study identify that the refraction status of abnormal refraction eye on women population in university students in South-East Korea have been more increased prevalence the myopia and astigmatism.

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Refractive Error in Middle and High School Pupils (중고등학생의 안굴절 상태조사 및 연구)

  • Pyo, Kyoung-Min;Kim, Woong-Tea
    • Journal of Korean Ophthalmic Optics Society
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    • v.1 no.1
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    • pp.119-125
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    • 1996
  • From 1995. 3. 20 to 1995. 4. 10 refractive errors were surveyed on the 1,197 middle and high school pupils in Dong-Du-Cuon area. On the basis of the power of the old glasses or newly examined power, we surveyed the distribution of the refractive errors according to their types, ages, heights, weights and differences between both eyes. Among 2,394 eyes examined, 1,125eyes(47%) were emmetropia, 967 eyes(40.4%) were myopic, and 302eyes(12.6%) were hyperopic. As to the distribution of refractive errors, simple myopia(42.9%) was most common, and mixed astigmatism and compound hyperopic astigmatism were below 1%, Among the types of astigmatism, 62% were with the rule, 23% were against the rule and 15% were oblique, Differences between both eyes, the left eye showed more myopic than those of right eye. The distribution of myopia according to their ages, 27.7 at age 11, 38.5% at age 12, 35.5% at age 41.5% at age 14, 37.7% at age 15, 48.3% at age 16 and 46.8% at age 17., there was a significant increase in the prevalence of the myopia but that or hyperopia decreases with increases of age.

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Measurement of Refractive Error and the Prescription for Ametropia with Refractometer and Visiontester (굴절이상과 시력교정)

  • Choe, Y.J.;Seo, Y.W.
    • Journal of Korean Ophthalmic Optics Society
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    • v.2 no.1
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    • pp.61-76
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    • 1997
  • In this paper, we found out the objective refractive errors, the full corrective refractive powers, and the prescriptions for 64 males and 36 females aged 18 to 26 years. To increase the unaided visual acuity 0.1 to the aided visual acuity 1.0 with the glasses, we needed the spherical equivalent refractive power of -3.00D for male and -2.91D for female respectively. To increase the unaided visual acuity 0.5 to the aided visual acuity 1.0 with the glasses, we needed the spherical equivalent refractive power of -0.5D for male and -1.38D for female respectively. Comparing unaided visual acuity and corrective refractive power, the more one has refractive error the less one has unaided visual acuity but these are not linear relationships. Comparing objective refractive error figures, full corrective refractive power figures and prescriptions, objective refractive error figures are the hightest, followed by full corrective refractive power figures. Prescriptions compared with the other two are lower. The cylindrical refractive powers are less than -2.50D. In this study, with the rule astigmatism is dominant over against the rule astigmatism and oblique astigmatism. The accommodation measured by push up method is 6.75D~10.04D for male and 7.50D~9.60D for female respectively.

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A Study for the Refractive Error in Middle and High School Pupils on the Basis of Their Glasses Power (안경도수를 근거로 한 중·고등학생의 굴절이상에 관한 연구)

  • Sung, Duk-Yong
    • Journal of Korean Ophthalmic Optics Society
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    • v.8 no.2
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    • pp.169-175
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    • 2003
  • This research reviewed that 83 male subjects. 89 female subjects of middle and high school visited D Optical shop at the downtown of Daegu more than twice from January, 1999 to January, 2003 and obtained the following results by using the visual acuity prescription of them for which D Optical shop was keeping. 1. The classification of correction power for 190 myopia eyes was examined (87 male eyes, 103 female eyes) showed 89 eyes(46.82%) between $0.25D{\leq}3.00D$, 86 eyes(45.26%) between $3.25D{\leq}6.00D$, 15 eyes(7.89%) for over 6.25D. 2. The kind of 154 astigmatism subjects(79 male eyes, 75 female eyes) was direct astigmatism 83.77%, reverse astigmatism 11.69%, oblique astigmatism 4.55%. The cylindrical correction power for astigmatic eyes was 61 eyes(39.61%) between $0.25D{\leq}0.50D$, 60 eyes(38.96%) between 0.50D<1.00D, 121 eyes(78.57%) for less than 1.06D, 6 eyes(0.65%) for over 3.00D. 3. The variation of spherical power showed 161 eyes(46.80%) between $0.00D{\leq}0.50D$, 109 eyes(31.69%) between $0.51D{\leq}1.00D$, 17 eyes(4.94%) for over 2.01D variation. 4. The variation of astigmatic power showed 92 eyes(59.74%) between $0.00D{\leq}0.50D$, 39 eyes(25.32%) between $0.26D{\leq}0.50D$, 10eyes (6.49%) between $0.51D{\leq}0.75D$, 13 eyes(8.44 %) for over 0.76D astigmatic variation. 5. The variation of equivalent spherical power showed 137 eyes(39.83%) between $0.00D{\leq}0.50D$, 126 eyes(36.63%) between $0.51D{\leq}1.00D$, 40 eyes(11.63%) between $1.01D{\leq}1.50D$, 21 eyes(6.10%) between $1.51D{\leq}2.00D$, 20 eyes(5.81%) for over 2.01D variation.

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Studies on Curved Diffractive Optical Elements in EUV (극자외선 영역에서 곡면 DOEs에 관한 연구)

  • Choi, Sung-Eul;Lee, Yong-Woo;Kwon, Myung-Hoi;Kim, Yong-Hoo
    • Korean Journal of Optics and Photonics
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    • v.16 no.4
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    • pp.304-312
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    • 2005
  • Field performance of several different types of diffractive optical elements(DOEs) has been carried out. Using Zemax model, we have designed five different types of DOEs, such as transmissive flat-DOE, transmissive curved-DOE, reflective flat-DOE, reflective curved-DOE and parabolic mirror, We have applied two different wavelengths, i.e., 13 m(EUV) and 632.8 nm(visible) to above DOEs. Off_axis dominate aberrations and the diffraction limiting (Rayleigh limit) field angles have been investigated and compared at both wavelengths for each DOE. At diffraction limit, field angle of curved-DOEs was much greater than that of flat-DOEs for both transmission and reflective types. We also showed that dominated off_axis aberration of flat-DOEs was coma, but that of curved-DOEs was mixture of astigmatism and curvature of field. The measured field angle and expected OPD aberrations were well coincided with theoretical ones. Increasing the ratio of field angle with wavelength was more effective in curved-DOEs than flat-DOEs.