Dynamic point shifting in null screen videokeratometry

M. I. Rodríguez-Rodríguez; A. Jaramillo Núñez; R. Díaz Uribe

doi:10.1117/12.903320

2 November 2011 Dynamic point shifting in null screen videokeratometry

M. I. Rodríguez-Rodríguez, A. Jaramillo Núñez, R. Díaz Uribe

Proceedings Volume 8011, 22nd Congress of the International Commission for Optics: Light for the Development of the World; 80119H (2011) https://doi.org/10.1117/12.903320
Event: International Commission for Optics (ICO 22), 2011, Puebla, Mexico

Abstract

For obtaining the shape of the corneal surface through the Null Screen method, a numeric integration procedure must be carried out; perhaps, the simplest integration method is the trapezoid rule. This method, however, is limited by the truncation error. It has been shown previously [1-6] that the point shifting method allows the reduction of this error by adding many more evaluation points so reducing the average spacing between evaluation points. To do so, an array of LCD's must be used to display the moving Null Screen. In this paper we propose to use three LCD forming a triangular prism, instead of a cylindrical Null Screen [3] for measuring the shape of the human corneas. The null screen design will be described and some experimental results obtained with calibration spheres used to simulate the corneal surface will be presented.

Citation Download Citation

M. I. Rodríguez-Rodríguez, A. Jaramillo Núñez, and R. Díaz Uribe "Dynamic point shifting in null screen videokeratometry", Proc. SPIE 8011, 22nd Congress of the International Commission for Optics: Light for the Development of the World, 80119H (2 November 2011); https://doi.org/10.1117/12.903320

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