Factors Affecting the Sensitivity and Specificity of the Heidelberg Retina Tomograph Parameters to Glaucomatous Progression in Disc Photographs
04/05/2010 0 Comments
The factors affecting the sensitivity and specificity of the vertical cup-to-disc ratio, the cup-to-disc area ratio, the cup volume, the rim area and a linear discriminant function to progression were analyzed to evaluate these factors affecting the sensitivity and specificity of the stereometric optic nerve head parameters of the Heidelberg Retina Tomograph to glaucomatous progression in stereoscopic ONH photographs.
These parameters were the best indicators of progression in a retrospective study of 476 eyes. The reference standard for progression was the masked evaluation of stereoscopic ONH photographs.
The factors having the most significant effect on the sensitivity and specificity of the stereometric ONH parameters were the reference height difference and the mean topography standard deviation (TSD), indicating image quality. Also, the change in the TSD and age showed consistent, but variably significant, influence on all parameters tested. The sensitivity and specificity improved when there was little change in the reference height, the image quality was good and stable, and the patients were younger. The sensitivity and specificity of the vertical cup to disc ratio was improved by a large disc area and high baseline cup to disc area ratio. The rim area showed a better sensitivity and specificity for progression with a small disc area and low baseline cup to disc area ratio.
The factors affecting the sensitivity and specificity of the stereometric ONH parameters to glaucomatous progression in disc photographs are essentially the same as those affecting the measurement variability of the HRT.
SOURCE: Saarela V, Falck A, Airaksinen PJ, Tuulonen A. Factors affecting the sensitivity and specificity of the Heidelberg Retina Tomograph parameters to glaucomatous progression in disc photographs. Acta Ophthalmol 2010;Mar 23 [Epub ahead of print].