A model for corneal endothelium specular microscopy images

Abstract

Abstract Purpose: As a part of an ongoing project on corneal endothelium morphometry by diffraction, a model for corneal endothelium specular microscopy (CSM) images has been developed. The simulator has been developed to as realistically as possibly emulate real CSM images. Development of the simulator was anticipated to be valuable in examining the impact of varying quality of CSM images on different methods of corneal endothelium morphometry. Methods: The model was written with the mathematical programming language MATLAB. An earlier version of the simulator was used to find theoretical functional relationships between cell density and cell size variation of the corneal endothelium and identifiable characteristics in the diffraction pattern, simulated using a numerical Fourier transform. Further development has added realism to the created images as well as ways of altering illumination profiles, image noise and contrast. Results: Currently, the simulation model allows creation of realistic clinical CSM images and variation of; CSM image size, cell size and density, regularity of cell shape, variation in cell size, frequency of illumination profile, weight of illumination profile, level of image distortion, and level of cell barrier contrast. Conclusions: There are several different CSM instruments on the market providing CSM images of varying quality. There are also a number of, often instrument specific, tools for analysis of CSM images resulting in measurement variation depending on instrument, patient and operator. It is anticipated that a simulation model that allows standardized variation of important characteristics in CSM images will be an important tool for evaluation of existing tools for analysis of CSM images and for creation of new improved alternatives.