Agreement among ophthalmologists in marking the optic disc and optic cup in fundus images.

The purpose of this paper was to study the agreement between six ophthalmologists who manually marked the optic nerve head using fundus images. Four different parameters were considered from the manual marking images: (1) disc (area and centroid), (2) cup (area and centroid), (3) horizontal and vertical cup-to-disc ratios, and (4) including the previous two parameters for both horizontal and vertical cup-to-disc ratios, and investigated the comprehensive agreement and accuracy among all the ophthalmologists. The best agreement percentage for all the parameters combined was between ophthalmologists number one and three for 44 % of images, and the best accuracy was for ophthalmologist number one with 77.4 % of 315 total tested images. Our analysis shows that more than half of the images in the dataset were not agreed upon when considering all the parameters together.