Measuring Corneal Topography Using Wavefront Analysis Technique

Refractive surgery has emphasized the need of accurate and precise methods for measuring the power of the human cornea. Available techniques for measuring corneal topography include keratometry, videokeratoscopy, and scanning slit imaging. A new type of instrument, a corneal topographer based on a Hartmann-Shack wavefront sensor for measuring corneal elevation over a spherical surface, is presented in this thesis. The performed tests of the topography system showed a high accuracy and reproducibility of the measurements on spherical as well as on toric test sample surfaces that approximate the curvature of the central human cornea. A comparison between the data obtained by the topographer and those provided by a videokeratoscope showed that the topographer is as precise as standard instruments used in clinical praxis. The measurements on human corneas demonstrated the importance of a Z-tracker module for the correct placement of the corneal surface. To enhance the accuracy of the topography system, a better tracking of the corneal position is necessary to compensate for the axial eye movements during the examination that strongly affect the measurements. Additionally, more clinical studies are necessary to test the topographer on human cornea and to give an evidence for the clinical acceptance of the instrument.

Level thesis:degree_level

thesis.doctoral

Grantor dc:publisher

Universität Heidelberg

Year

2004

Author dc:creator

• Korablinova, Nina

Contributors dc:contributor

• Bille, Josef

Repository record source_url

http://www.ub.uni-heidelberg.de/archiv/6564

OAI identifier oai:identifier

oai:archiv.ub.uni-heidelberg.de:6564