Topographic changes in the optic disc in eyes with cotton-wool spots and primary open-angle glaucoma.

Changes in the topography of the optic disc in 26 eyes with cotton-wool spots displaying defects in the retinal nerve-fiber layer and in 31 eyes with early primary open-angle glaucoma showing a similar degree of such defects were studied by computer-assisted optic disc analyzer and then compared with 27 controls. Changes in the cup-to-disc ratio, cup volume, and ratio of rim area to disc area were not significant in eyes with cotton-wool spots. The quotient of cup volume divided by cup-to-disc ratio eyes with of primary open-angle glaucoma was greater than that in eyes with cotton-wool spots. For the detection of nerve loss in eyes with cotton-wool spots, the image analyzer, which identified the notches in the horizontally sectioned contour line of the cup, was more sensitive than stereoscopic detection of the notches in the rim (P less than 0.05). The image analyzer enabled the detection of slight nerve-fiber loss by examination of the contour line of the cup in eyes with cotton-wool spots.