Multivariate assessment of computer-analyzed corneal topographers.

نویسندگان

  • M A Viana
  • I Olkin
  • T T McMahon
چکیده

Methodological aspects of multivariate statistical models to describe and to assess data from computer-analyzed corneal topographers (CACT) are considered. The data generated by repeated curvature mappings of calibrated steel balls are discussed in detail with the objective of formulating the basic questions and suggesting directions to assess data from clinical applications of CACT. The interpretation of seemingly straightforward concepts such as accuracy and precision is revisited with the objective of understanding its meaning in future clinical and experimental applications of CACT. Some of the statistical problems related to the analysis of corneal astigmatism based on CACT data are also discussed.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Corneal topography in keratoconus: state of the art.

The morphological characterization of the cornea using corneal topographers is a widespread clinical practice that is essential for the diagnosis of keratoconus. The current state of this non-invasive exploratory technique has evolved with the possibility of achieving a great number of measuring points of both anterior and posterior corneal surfaces, which is possible due to the development of ...

متن کامل

Asphericity of the anterior human cornea with different corneal diameters.

PURPOSE To measure the anterior corneal asphericity (Q) with different corneal diameters. SETTING Department of Physics (Optometry), University of Minho, Braga, Portugal. METHODS Thirty-six eyes of 36 patients were evaluated using a videokeratoscope, and the Q-values were recorded. Topographic data were also analyzed using Vol-CT 6.89 software (Sarver & Associates, Inc) to obtain the Q-valu...

متن کامل

Computer Algorithm for Simulation of the Human Optical System and Contribution of the Cornea to the Optical Imperfections of the Eye

The main objective of this work is to demonstrate the relation between corneal surface imperfections and retinal image imperfections. Its originality resides on the fact that specialized literature approximate the eye and the cornea as mathematical surfaces to explain simple refraction problems (myopic, hyperopic, astigmatic), whereas in the present work we have used topographic data for in viv...

متن کامل

Corneal Topography: A review, new ANSI standards and problems to solve

This review of corneal topography has three sections: 1. a brief introduction to how corneal topography instruments work. A quantitative comparison of the relative accuracy of slope based and position based instruments is presented. 2. a summary of and commentary on the newly issued ANSI standards for corneal topography. 3. an examination of problems still facing corneal topography. OCIS codes:...

متن کامل

Repeatability and concordance of the Pentacam system. Comparative study of corneal parameters measured with Pentacam and Atlas Repetibilidad y concordancia de un sistema Pentacam. Comparación de parámetros corneales medidos con Pentacam y con Atlas

REFERENCES AND LINKS [1] W. N. Charman, “The retinal image in the human eye”, in Progress in Retinal Research, Pergamon, Oxford (1983). [2] A. A. Atchison, G. Smith, Optics of the Human Eye, Butterworth-Heinnemann, Oxford (2000). [3] P. Artal, A. Guirao, “Contribution of corneal and lens to the aberrations of the human eye”, Opt. Lett. 23, 1713-1715 (1998). [4] A. Guirao, P. Artal, “Corneal wav...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Journal of the Optical Society of America. A, Optics, image science, and vision

دوره 10 8  شماره 

صفحات  -

تاریخ انتشار 1993