• Title/Summary/Keyword: Toric

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Clinical Evaluation of Prism-stabilized Toric Soft Contact Lens Fit (프리즘 안정화 디자인 토릭 소프트 콘택트렌즈 피팅에 대한 임상 평가)

  • Kim, Soo-Hyun;Kim, Jai-Min
    • Journal of Korean Ophthalmic Optics Society
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    • v.15 no.2
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    • pp.137-144
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    • 2010
  • Purpose: This study was to evaluate the clinical performance of 1-Day disposable toric soft contact lenses (TSCL) and to compare the visual performance with glasses and TSCL. Methods: In a two-week investigation of 'prism ballast' designed TSCL, occular refractions in 15 (30 eyes) healthy subjects were within the range of -2.75 D TO -8.00 D spherical power and -0.75 DC to -2.25 DC cylinderical power (with-the-rule). Subjects were assessed the clinical performance (orientation, centration, movement, tightness, rotation recovery, symptoms) of TSCL and compared binocular vision and contrast sensitivity with corrected glasses and TSCL at initial and two-week follow-up visits. Results: The prism-ballast design TSCL achieved better orientation, rotation recovery and symptoms over 2 week period. There was no statistically significant difference between spectacles and TSCL with respect to measuring binocular vision and contrast sensitivity. Conclusions: The clinical performance was good with prism-ballast design toric soft contact lenses. Evaluation of binocular vision and contrast sensitivity did not show the differences between spectacles and TSCL correction. This study suggests that TSCL wearers can be achieved similar visual performance for spectacles wearers.

Accuracy of Astigmatic Correction Using Toric Intraocular Lens by Position and Size of Corneal Incision (각막절개 위치와 크기에 따른 난시교정인공수정체의 난시교정의 정확성)

  • Park, Wookyung;Kim, Man Soo;Kim, Eun Chul
    • Journal of The Korean Ophthalmological Society
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    • v.60 no.2
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    • pp.126-134
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    • 2019
  • Purpose: To assess the accuracy of toric intraocular lens (IOL) implantation by the location and size of the corneal incision. Methods: We retrospectively reviewed the medical records of 98 patients (98 eyes) who underwent phacoemulsification with toric IOL implantation from January 2014 to March 2017. The patients were divided into two groups: group 1 got an incision of the superior side of the cornea (n = 54) and group 2 received an incision on the temporal side of the eye (n = 44). For both groups, incisions were made at their steep corneal astigmatism axises. Each group was further divided into subgroups for whom different sized blades were employed (2.75 vs. 2.2 mm widths). We measured the refractive index and autokeratometric parameters. We postoperatively assessed residual astigmatism and any reduction thereof. Results: In both groups, uncorrected and best-corrected visual acuity, refraction cylinder astigmatism, and autokeratometric astigmatism improved statistically. Between two groups, corneal astigmatism decrease was not significant. Residual astigmatism also showed no significant differences between the two. Patients in both groups treated using 2.75 mm wide blades exhibited greater increases in corneal astigmatism. Conclusions: During cataract surgery, precise correction of astigmatism via toric IOL implantation is possible when surgically induced astigmatism is minimized by careful choice of the location and size of the corneal incision.

A Correlation between Axis-Rotation and Corneal Eccentricity in Toric Soft Contact Lens Fitting in With-the-rule Astigmatism (직난시안에서의 토릭소프트렌즈 피팅 시 축 회전과 각막이심률과의 상관관계)

  • Park, Hyung Min;Park, Kyounghee;Kim, So Ra;Park, Mijung
    • Journal of Korean Ophthalmic Optics Society
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    • v.19 no.3
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    • pp.305-313
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    • 2014
  • Purpose: A correlation between the rotating direction and rotation amount according to the eccentricity was analyzed in the present study when fitting the toric soft contact lens. Methods: One hundred fourteen eyes of with-the-rule astigmatism in 20s and 30s were appropriately applied toric soft contact lens by the guideline of manufacturer and fitting evaluations and analyzed the rotating direction and rotation amount when fixating at primary position and 8 different directions of gaze. The speed of reorientation and the correlation between the rotation amount and cornea eccentricity were also analyzed when rotating $45^{\circ}$ each toward the temporal and nasal direction. Results: The cornea eccentricity and rotation amount was shown positive correlation. For the gaze of direction, it was identified that the gaze of directions other than the gaze of direction towards the nasal and temporal had correlation, and among them, the gaze of directions to superior and the superior-temporal showed the tendency of decreasing rotation amount as the cornea eccentricity increased. On the contrary, the gaze of direction towards the inferior, inferior-temporal, superior-nasal, and inferior-nasal showed tendency of increasing rotation amount as the cornea eccentricity increased thus, it was identified that the cornea eccentricity showed different correlation according to the gaze of direction. For the case of re-orientational speed, the speed of lens reorientation in the group having the smallest corneal eccentricity was fastest in both direction but was not significantly different. Conclusions: Considering cornea eccentricity to current method of prescribing toric soft contact lens which is based on total astigmatism, it will be helpful to establish the optimal axis stabilization.

Analysis of Axial Mis-alignment After Wearing of Toric Soft Contact Lenses (토릭소프트콘택트렌즈의 착용 후 축 정렬 상태의 변화 분석)

  • Kim, Sang-Yoeb;Lee, Dong Yeol;Lee, Sun-Haeng;Kim, Kun-Kyu;Song, Sop;Cho, Hyun Gug
    • Journal of Korean Ophthalmic Optics Society
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    • v.15 no.3
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    • pp.213-217
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    • 2010
  • Purpose: To emphasize the necessity of post-fitting by follow-up test, the mis-alignment was analyzed after initial wearing of toric soft contact lenses (TSCL). Methods: After trial contact lenses were worn to 87 eyes with myopic astigmatism for 1 week, we observed the alignment of axis mark on trial contact lenses using slit lamp and corrected the rotated axis by method of LARS. After final fitting, rotation ratio, rotation degree and rotation position were analyzed compared to initial prescription divided to amount of cylinderical and spherical powers. Results: Rotation ratio of TSCL's axis was increased as increment of both cylinderical powers and (-)spherical powers. An average of rotation degree was $10^{\circ}{\sim}13^{\circ}$ which was not related to amount of their powers. Rotation position of TSCL's axis was more to temporal than to nasal. Conclusions: Because mis-alignment of axis after TSCL wearing induce the poor sight, adjustment of axial alignment as a result of follow-up must be performed.

A NOTE ON GRÖBNER FANS OF IDEALS

  • KIM, YONGGU
    • Honam Mathematical Journal
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    • v.21 no.1
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    • pp.19-33
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    • 1999
  • In this paper we reproduce results on $Gr{\ddot{o}}bner$ fans of ideals following a paper by T. Mora and L. Robbiano [5], and introduce stable $Gr{\ddot{o}}bner$ fans of ideals introduced by D. Mall [4]. We make minor corrections for the clarification, simplify proofs and provide new proofs. At the end we give a description of $Gr{\ddot{o}}bner$ fans of toric ideals.

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CALABI-YAU THREEFOLDS FROM BUILDING BLOCKS OF G2-MANIFOLDS

  • Lee, Nam-Hoon
    • Journal of the Chungcheong Mathematical Society
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    • v.30 no.3
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    • pp.331-335
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    • 2017
  • We construct Calabi-Yau threefolds by smoothing normal crossing varieties, which are made from the building blocks of $G_2-manifolds$. We compute the Hodge numbers of those Calabi-Yau threefolds. Some of those Hodge number pairs ($h^{1,1}$, $h^{1,2}$) do not overlap with those of Calabi-Yau threefolds constructed in the toric setting.

EFFICIENTLY COMPUTING TORUS CHARTS IN LANDAU-GINZBURG MODELS OF COMPLETE INTERSECTIONS IN GRASSMANNIANS OF PLANES

  • Prince, Thomas
    • Bulletin of the Korean Mathematical Society
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    • v.54 no.5
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    • pp.1719-1724
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    • 2017
  • In this note, companion to the paper [10], we describe an alternative method for finding Laurent polynomials mirror-dual to complete intersections in Grassmannians of planes, in the sense discussed in [10]. This calculation follows a general method for finding torus charts on Hori-Vafa mirrors to complete intersections in toric varieties, detailed in [5] generalising the method of [8].

Finite Raytracing Through Non-rotationally Symmetric Systems (비대칭형 광학계의 유한광선추적)

  • 홍경희
    • Korean Journal of Optics and Photonics
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    • v.1 no.2
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    • pp.217-222
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    • 1990
  • A general ray tracing scheme has been developed for using a personal computer which trace finite rays through any non-rotationally symmetric system. This scheme may be used for the surface type such as conic section with or without aspherics, toric surfaces, sagittal and tangential cylindrical sections and axicons. Specially, any combinational of decentered, tilted and rotated surfaces has been considered. Before transfering to the next surfaces, the local coordinates are refered back to an initial reference coordinate system. We can get a mathmtical model of a non-rotationally symmetrical finite ray trace running on an inexpensive personal computer.

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