Quality criteria for astigmatic aberrated fundus images

PURPOSE: We search for an a priory criteria for quality of astigmatic aberrated fundus images in order to estimate minimal their details being able detected still. DESIGN: We model distortions of fundus images caused by astigmatism using computer simulation and calculate integral quality criteria of the images. SUBJECTS: High resolution fundus images from open-source databases (both healthy and with signs of diabetic retinopathy). METHODS: Under incoherent isoplanar approach we convolute initial images with system optical transfer function for simulation of distorted images. We calculate full reference quality criterion and compare it with non-reference criteria to calibrate their output for a priory quality estimation. MAIN OUTCOME MEASURES: We calibrate mentioned criteria output (in arbitrary units) against the magnitude of astigmatism in diopters (D) and the corresponding radius of optical impulse response function in micrometers (um). RESULTS: We estimate that if the magnitude of the eye astigmatism exceeds 0.7D, the minimal image details is greater than 15 um, and the output of selected non-reference criterion will be less than 20 comparing to 70 for non-distorted images. CONCLUSIONS: Mentioned approach permits using selected a priory criterion to calculate quality of astigmatic distorted fundus images and to estimate the their minimal details which maybe reliably detected.