A comparison of two or more disc fluorescein angiograms performed on separate occasions was done on 60 eyes of normal subjects and patients with ocular hypertension, primary open-angle glaucoma, and low-tension glaucoma. Clinically stable patients did not show any change in their disc angiographic filling patterns. Eyes that developed new visual-field defects with increased disc cupping and pallor correspondingly showed new absolute filling defects or areas of hypofluorescence. In those with established field defects, however, further changes in the visual field occurred without obvious changes in the disc fluorescein filling defect. Surgical lowering of intraocular pressure with or without decrease in disc cupping and pallor did not result in visible improvement of the disc angiographic pattern. Thus, the development of new visual-field defects is associated with changes of the circulation of the optic disc.