• Title/Summary/Keyword: Toric

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Rotational Stability of AcrySof Toric Intraocular Lens Over Time: Influence of Capsulorhexis Contraction

  • Kim, Joong Hee;Cho, Kyong Jin
    • Medical Lasers
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    • v.9 no.1
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    • pp.44-50
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    • 2020
  • Background and Objectives To evaluate the rotational stability of AcrySof toric intraocular lenses (IOL) by considering lapse of postoperative time and influence of capsulorhexis contraction. Materials and Methods A prospective, masked, single center study was conducted on 19 patients who had undergone microcoaxial cataract surgery and AcrySof toric IOL implantation. Slit-lamp retroillumination photographs of anterior segments were obtained from all patients after 1 week, 1 month and 3 months post-surgery. The degree of alteration of the postoperative IOL axis alignment and the amount of anterior capsular shrinkage were analyzed using Adobe Photoshop software. Results The mean degree of toric IOL axis misalignment was 2.18 (±20.2) degrees at 3 months follow-up. Quadrant analysis of the capsulorhexis aperture area at 1 week and 1 month post-operative, showed counterclockwise IOL rotation when the capsule contraction was dominant in the haptic part as well as clockwise rotation when dominant in the non-haptic part (p = 0.015). Conclusion The direction and degree of AcrySof toric IOL rotation differed throughout the follow-up period. Since most misalignments were found on the first post-operative day, physicians should try to minimize peri-operative risk factors that influence IOL rotation. There was also a correlation between the part of anterior capsule contraction and the direction of IOL rotation.

SIMPLICIAL WEDGE COMPLEXES AND PROJECTIVE TORIC VARIETIES

  • Kim, Jin Hong
    • Bulletin of the Korean Mathematical Society
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    • v.54 no.1
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    • pp.265-276
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    • 2017
  • Let K be a fan-like simplicial sphere of dimension n-1 such that its associated complete fan is strongly polytopal, and let v be a vertex of K. Let K(v) be the simplicial wedge complex obtained by applying the simplicial wedge operation to K at v, and let $v_0$ and $v_1$ denote two newly created vertices of K(v). In this paper, we show that there are infinitely many strongly polytopal fans ${\Sigma}$ over such K(v)'s, different from the canonical extensions, whose projected fans ${Proj_v}_i{\Sigma}$ (i = 0, 1) are also strongly polytopal. As a consequence, it can be also shown that there are infinitely many projective toric varieties over such K(v)'s such that toric varieties over the underlying projected complexes $K_{{Proj_v}_i{\Sigma}}$ (i = 0, 1) are also projective.

Correlations between Axial Rotation of Toric Soft Contact Lenses and Corneal Eccentricity according to the Wearing Time and Gaze Directions (착용시간 및 응시방향에 따른 토릭소프트콘택트렌즈의 축 회전과 각막이심률과의 상관관계)

  • Seo, Woo Hyun;Kim, So Ra;Park, Mijung
    • Journal of Korean Ophthalmic Optics Society
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    • v.21 no.1
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    • pp.35-45
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    • 2016
  • Purpose: The present study was aimed to investigate the effect of corneal eccentricity on the axial rotation when wearing toric soft contact lenses were worn for certain time and changing the gaze directions. Methods: Toric soft contact lenses with double thin zone design applied on 85 of with-the-rule astigmatic eyes. Then, rotational direction and amount of contact lenses were measured after 15 minutes and 6 hours of lens wear. The difference was further compared and analyzed according to corneal eccentricity. Results: The rotation of toric lens showed a tendency to rotate to temporal direction in all gaze directions except temporal-upper direction in all groups of corneal eccentricity. The amount of lens rotation in the frontal gaze direction exhibited a negative correlation since the amount was decreased with increasing corneal eccentricity after both 15 minutes and 6 hours of lens wearing. In many cases, the cornea with small eccentricity also showed the lens rotation larger than $10^{\circ}$. The difference in rotational amount after 15 minutes of toric lens wear was small according to the corneal eccentricity however, the change of rotational amount of contact lens according to corneal eccentricity was shown after 6 hours of lens wear. Conclusions: The present study revealed that the amount of axial rotation was largely varied according to the wearer's corneal eccentricity when wearing toric lens and the rotational amount after certain time of lens was also affected by corneal eccentricity. Thus, it is suggested that the selection of toric soft contact lenses based on corneal eccentricity is necessary.

Axial Rotation of Toric Soft Lens by Corneal Astigmatism and Change of Posture (각막난시와 자세 변화에 의한 토릭소프트렌즈의 축 회전)

  • Kim, So Ra;Kim, Hyun Sun;Jung, Ga Won;Park, Hyung Min;Park, Sang Hee;Park, Mijung
    • Journal of Korean Ophthalmic Optics Society
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    • v.18 no.4
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    • pp.441-447
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    • 2013
  • Purpose: The present study was conducted to investigate the axial rotations of toric soft lens during the change of lens wearer's posture, and the relationship between its rotation and corneal astigmatism. Methods: The amount, direction, and speed of toric soft contact lens rotation were measured for 42 eyes (aged 20s) with the rule astigmatism in the straight and lying postures, and it compared between their changes according to corneal astigmatism. Results: There was no significant difference in the axial rotation of lens for the astigmatism prescription between the straight and lying postures. However, the rotation angle was significantly different according to the posture of lens wearer. Rotating directions in straight posture were nasal direction for 20 eyes and temporal direction for 22 eyes. In lying posture, lenses of most wearers were rotated to a direction of lying posture, and the initial rotating speed was very fast in initial wearing for -0.75 D toric lenses, but consistency for -1.25 D toric lenses. The rotation angle in lying posture showed significantly different according to the amount of corneal astigmatism, the lens speed was also significantly different according to the wearing time but not the amount of corneal astigmatism. Conclusions: The axial rotation of toric soft lens was different by the lens wearer's posture and its amount was the greater with the higher degree of corneal astigmatism. Thus, these factors should be considered for the development of toric lens design.

Contrast Sensitivity and Glare with Spherical and Toric Soft Contact Lenses in Low-astigmatic Eyes (구면과 토릭 소프트 렌즈로 교정한 약도 난시안의 대비감도와 눈부심)

  • Lee, Min-Ah;Kim, Hyun Jung;Kim, Jai-Min
    • Journal of Korean Ophthalmic Optics Society
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    • v.14 no.1
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    • pp.39-45
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    • 2009
  • Purpose: The purpose of this study is to compare the visual performance by contrast sensitivity (CS) and disability glare (DG) in low astigmatic eyes corrected with toric soft lenses and other optical corrections. Methods: Twenty university students with myopia (-1.00 to -6.50D Sph. with astigmatism up to 1.50 cyl) were enrolled and corrected by five different methods: 1) soft toric lenses; 2) spherical soft contact lenses; 3) RGP lenses; 4) best spectacle corrected visual acuity; 5) spherical equivalent spectacles. All subjects had corrected vision acuity of 20/20 or better. Contrast sensitivity and disability glare were measured using the OPTEC 6500 contrast sensitivity view-in tester included the EyeView Functional Vision Analysis software at photopic or mesopic conditions with glare. Results: At photopic condition, best corrected spectacle wearers had the highest monocular contrast sensitivity at all spatial frequency followed by soft toric lenses, RGP lenses, spherical equivalent spectacles, and spherical soft contact lenses. However, all of them were in normal contrast sensitivity value at photopic condition. At mesopic condition with glare, toric soft lenses were the highest and followed by RGP lenses, spherical equivalent spectacles, best spectacle corrected visual acuity and spherical soft contact lenses. It was observed that spherical soft contact lens wearers demonstrated lower range than normal contrast sensitivity value at mesopic condition with glare. Conclusion: Toric soft lenses gave better visual performance than spherical soft lenses in low astigmatic eyes. Subjects requiring the use of contact lenses under mesophic conditions could benefit from toric soft lenses.

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Projectivity for 3-Dimensional Compact Nonsingular Toric Varieties

  • Park, Hye Sook
    • Journal of the Chungcheong Mathematical Society
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    • v.6 no.1
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    • pp.95-104
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    • 1993
  • There are some sufficient or necessary conditions about projectivity for toric varieties. We consider one of them and state some conditions about projectivity for a 3-dimensional compact nonsingular case which is obtained from a projective one by nonsingular equivariant blow-down.

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Change in Axial Rotation of Toric Soft Contact Lens according to Tear Volume (눈물양에 따른 토릭 소프트콘택트렌즈의 축 회전양 변화)

  • Seo, Woo Hyun;Kim, So Ra;Park, Mijung
    • Journal of Korean Ophthalmic Optics Society
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    • v.20 no.4
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    • pp.445-454
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    • 2015
  • Purpose: The present study was aimed to investigate the effect of tear volume on a change of axial rotation according to wearing time of toric soft contact lens and gaze directions. Method: Toric soft contact lenses with double thin zone design applied on 62 eyes. Then, changes in non invasive tear film break-up time and the rotational direction/amount of lens when changing gaze direction were respectively measured after 15 minutes and 6 hours of lens wear. Results: Lens rotation to temporal direction was more found when changing gaze direction after lens wear. However, its rotation was varied according to wearing time and the subjects' tear volume. Furthermore, the frequency of lens rotation to temporal direction was higher in dry eyes compared with normal eyes at nearly all gaze directions after 15 minutes and 6 hour of lens wear. The rotational amount of lens was generally greater in dry eyes after 15 minutes of lens wear. However, its difference between normal eyes and dry eyes was not great after 6 hours of lens wear. Conclusion: The present study revealed that axial rotation of toric soft contact lens was varied according to the wearer's tear volume and lens rotational patterns at the initial, and extending periods of lens wear were different. The change in rotational pattern of toric soft contact lens from these results means the possibility of visual change after extending lens wear, and the identification of its correlation with tear volume suggests the necessity of considering factors for choosing appropriate toric soft contact lens.

ON TORIC HAMILTONIAN T-SPACES WITH ANTI-SYMPLECTIC INVOLUTIONS

  • Kim, Jin Hong
    • Bulletin of the Korean Mathematical Society
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    • v.59 no.3
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    • pp.671-683
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    • 2022
  • The aim of this paper is to deal with the realization problem of a given Lagrangian submanifold of a symplectic manifold as the fixed point set of an anti-symplectic involution. To be more precise, let (X, ω, µ) be a toric Hamiltonian T-space, and let ∆ = µ(X) denote the moment polytope. Let τ be an anti-symplectic involution of X such that τ maps the fibers of µ to (possibly different) fibers of µ, and let p0 be a point in the interior of ∆. If the toric fiber µ-1(p0) is real Lagrangian with respect to τ, then we show that p0 should be the origin and, furthermore, ∆ should be centrally symmetric.

A Survey about Wearing Soft Contact Lenses for Astigmatism Correction of The Local College Students, Gyeongsangnam-Do, Korea (경남지역 대학생들의 난시 교정용 소프트 콘택트렌즈의 착용에 관한 설문조사)

  • Kim, Bong-Hwan;Han, Seon-Hee;Kim, Dae-Hyeon;Byeon, Sang-Hyeon;Chae, Jeong-Im;Kim, Jae-Seok;Hwang, Yun-Jeong;Kim, Hak-Jun
    • Journal of Korean Clinical Health Science
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    • v.3 no.3
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    • pp.378-389
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    • 2015
  • Purpose. The actual status of wearing toric soft contact lenses was investigated to learn why it is not used although it is required. Materials and Methods. This study has studied 64 contact lens wearing the local college students, Gyeongsangnam-do who are 20.17(${\pm}0.70$)years old, by measuring their refractive power and over-refractive power with auto refractometer(HRK-8000A, Huvitz, Korea). In addition to that, a survey was done to figure out why they do not wear toric soft contact lenses, the purpose of using toric soft contact lenses, whether they have astigmatism or any knowledge about it, the kinds of contact lens, whether they are willing to buy corrective lenses, and how they are satisfied after purchasing them. Results. 17 students (21.9%) said they experienced light-spread; 9 students (14.1%)said that they have dizziness when they wear contact lens all day long. In the survey to see whether they had astigmatism or not, 37 students (57.8%) said they had it. For the reason they do not wear toric soft contact lenses, 33 students (51.6%) said that "they were prescribed regardless of astigmatism in the optometrist." To the question asking if they are willing to buy toric soft contact lenses according to the existence of astigmatism, 51 students (79.6%) answered they are. 31 students (48.4%) said they heard a description about astigmatism at the time of purchase for contact lens. Conclusion. As the ways for any people who need to correct astigmatism to wear corrective lens, enough education about astigmatism and consistent follow-up management are needed, where the role of optometrist is considered important.