Discrimination in Paired Data Situations

Paired data occur in a natural way in ophthalmology and other medical fields concerning paired organs. In our paper we deal with the diagnosis of the eye disease “glaucoma” using quantitative measurements. We compare discriminant analysis to the conditional Rosner model. We derive a characterization of the Rosner model as a special case of linear discriminant analysis and present a simple graphical display which allows to check the assumptions of the Rosner model and the impact of diagnostic information from the fellow eye. In our clinical example, for known disease status of the fellow organ, pathological values of this organ decreased the disease probability of the selected organ.