Reproducibility of the optic nerve head topography with a new laser tomographic scanning device.

Abstract

Laser scanning tomography has been shown to be an accurate and reliable method for the assessment of the three-dimensional optic disc topography. The authors investigate the reliability of morphometric measurements with the Heidelberg retina tomograph, a new instrument which was designed based on this technology, which simplifies handling and is much smaller than the laser tomographic scanner. Three independent measurements of the optic disc were performed in 39 eyes of 39 patients which were equally divided into the following three groups: glaucoma, glaucoma suspects, and controls. The mean coefficient of variation for measurement in the glaucoma, glaucoma suspect, and control groups was 2.9%, 5.0%, and 3.4%, respectively, for cup area; 4.9%, 4.6%, and 4.6%, respectively, for cup volume; 5.2%, 3.8% and 3.3%, respectively, for mean cup depth; and 5.2%, 4.1%, and 4.0%, respectively, for maximal cup depth. The mean standard deviation for one pixel of the total image was 30 +/- 6 microns, 28 +/- 7 microns, and 22 +/- 6 microns for the three groups, respectively. The Heidelberg retina tomograph enables fast and reliable measurement of the optic disc topography and therefore may allow exact follow-up of patients.