Retinal exudates are a common manifestation of damage of the human eye ground. An adaptive threshold algorithm was developed to detect and to measure the exudates in gray value images of patients with diabetic retinopathy. The images of the eye ground were acquired by monochromatic illumination of a scanning laser ophthalmoscope. By means of a dynamic thresholding procedure, we are able to omit the common usual preprocessing shading correction since the compensation of irregularities of illumination is implicitly contained in the algorithm. In order to get an objective assessment e.g. of the course of a disease or the success of a therapy we take into account the area as well as the location of the retinal exudates. The analysis is operator independent except for the choice of an area of interest.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.