Automatic detection of microdots in the stromal layer of corneal images

Microdots are bright, 1-2um features of the cornea. It has not been proven what these dots represent, but they are thought to be remnants of apoptotic cell death, such as lipofuscin granules. Their presence has been shown to correlate with corneal aging and extended contact use, both of which are linked to oxygen deprivation in the cornea. Confocal images of the stroma show these microdots mixed with larger keratocyte cells. This paper presents a method for detecting microdots using a two-step filtering scheme that separates the keratocyte cells and the microdots. Keratocyte cell locations are then used to eliminate falsely detected microdots. Results are compared to ground truth based on a grading scale from 0-5. Two graders were given a set of 50 images to grade using a GUI that included sample images for each of the six grades. The two graders had a correlation of .88 with each other. The algorithm had a correlation of .88 with the average of graders and .85 with each of the graders individually.