The two-point fluorophotometry technique was used to analyze quantitatively absolute fluorescein filling defects or hypofluorescent areas in glaucomatous optic discs. Significant differences were found between hypofluorescent and normal fluorescent areas. The hypofluorescent areas had slower and lesser filling of fluorescein and a slower disappearance of fluorescein compared with normal fluorescent areas. Also, the hypofluorescent areas showed a slow and persistent accumulation of fluorescein. Age, blood pressure, ocular pressure, and percent area of optic disc pallor were significantly correlated with changes in the circulation in the areas of normal fluorescence and hypofluorescence. This study suggests a decreased blood flow and a smaller vascular bed together with narrower vessels and increased permeability of the vessels in the hypofluorescent areas.