Evaluation of the Shape Symmetry of Bilateral Normal Corneas in a Chinese Population

被引:25
作者
Bao, Fangjun [1 ]
Chen, Hao [1 ]
Yu, Ye [1 ]
Yu, Jiguo [1 ]
Zhou, Shi [1 ]
Wang, Jing [1 ]
Wang, QinMei [1 ]
Elsheikh, Ahmed [2 ,3 ,4 ]
机构
[1] Affiliated Eye Hosp, WenZhou Med Coll, Wenzhou, Peoples R China
[2] Univ Liverpool, Sch Engn, Liverpool L69 3BX, Merseyside, England
[3] Moorfields Eye Hosp, NHS Fdn Trust, Biomed Res Ctr, Inst Hlth Res, London, England
[4] UCL Inst Ophthalmol, London, England
来源
PLOS ONE | 2013年 / 8卷 / 08期
基金
英国工程与自然科学研究理事会; 美国国家卫生研究院;
关键词
ZERNIKE POLYNOMIALS; MEASUREMENT ERROR; TOPOGRAPHY; ASTIGMATISM; KERATOCONUS; PACHYMETRY; THICKNESS; EYES;
D O I
10.1371/journal.pone.0073412
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
Purpose: To investigate the bilateral symmetry of the global corneal topography in normal corneas with a wide range of curvature, astigmatism and thickness values Design: Cross-Sectional Study Methods: Topography images were recorded for the anterior and posterior surfaces of 342 participants using a Pentacam. Elevation data were fitted to a general quadratic model that considered both translational and rotational displacements. Comparisons between fellow corneas of estimates of corneal shape parameters (elevation, radius in two main directions, R-x and R-y, and corresponding shape factors, Q(x) and Q(y)) and corneal position parameters (translational displacements: x(0), y(0) and z(0), and rotational displacements: alpha, beta and gamma) were statistically analyzed. Results: The general quadratic model provided average RMS of fit errors with the topography data of 1.7 +/- 0.6 mu m and 5.7 +/- 1.3 mm in anterior and posterior corneal surfaces. The comparisons showed highly significant bilateral correlations with the differences between fellow corneas in R-x, R-y, Q(x) and Q(y) of anterior and posterior surfaces remaining insignificantly different from zero. Bilateral differences in elevation measurements at randomly-selected points in both corneal central and peripheral areas indicated strong mirror symmetry between fellow corneas. The mean geometric center (x(0), y(0), z(0)) of both right and left corneas was located on the temporal side and inferior-temporal side of the apex in anterior and posterior topography map, respectively. Rotational displacement angle alpha along X axis had similar distributions in bilateral corneas, while rotation angle beta along Upsilon axis showed both eyes tilting towards the nasal side. Further, rotation angle gamma along Z axis, which is related to corneal astigmatism, showed clear mirror symmetry. Conclusions: Analysis of corneal topography demonstrated strong and statistically-significant mirror symmetry between bilateral corneas. This characteristic could help in detection of pathological abnormalities, disease diagnosis, measurement validation and surgery planning.
引用
收藏
页数:10
相关论文
共 31 条
[1]   Topography-driven excimer laser for the retreatment of decentralized myopic photorefractive keratectomy [J].
Alessio, G ;
Boscia, F ;
La Tegola, MG ;
Sborgia, C .
OPHTHALMOLOGY, 2001, 108 (09) :1695-1703
[2]   Bilateral symmetry analysis of breast MRI [J].
Alterson, R ;
Plewes, DB .
PHYSICS IN MEDICINE AND BIOLOGY, 2003, 48 (20) :3431-3443
[3]  
[Anonymous], INT CONTACT LENS CLI
[4]   A comparison of a topography-based rigid gas permeable contact lens design with a conventionally fitted lens in patients with keratoconus [J].
Bhatoa, Nawtej S. ;
Hau, Scott ;
Ehrlich, Daniel P. .
CONTACT LENS & ANTERIOR EYE, 2010, 33 (03) :128-135
[5]   Measurement error and correlation coefficients [J].
Bland, JM ;
Altman, DG .
BRITISH MEDICAL JOURNAL, 1996, 313 (7048) :41-42
[6]   Statistics notes: Measurement error proportional to the mean .23. [J].
Bland, JM ;
Altman, DG .
BRITISH MEDICAL JOURNAL, 1996, 313 (7049) :106-106
[7]   Mapping collagen organization in the human cornea: Left and right eyes are structurally distinct [J].
Boote, C ;
Hayes, S ;
Abahussin, M ;
Meek, KM .
INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE, 2006, 47 (03) :901-908
[8]   Axes of astigmatism in fellow eyes show mirror rather than direct symmetry [J].
Guggenheim, Jeremy A. ;
Zayats, Tetyana ;
Prashar, Ankush ;
To, Chi Ho .
OPHTHALMIC AND PHYSIOLOGICAL OPTICS, 2008, 28 (04) :327-333
[9]  
GUILLON M, 1986, OPHTHAL PHYSL OPT, V6, P47, DOI 10.1111/j.1475-1313.1986.tb00699.x
[10]   Optimal modeling of corneal surfaces with Zernike polynomials [J].
Iskander, DR ;
Collins, MJ ;
Davis, B .
IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING, 2001, 48 (01) :87-95