A fluorescein angiography of the optic disc has been performed on 62 eyes in 41 patients suffering from ocular hypertension or glaucoma. The angiogram was abnormal in 32 eyes. 11 eyes showed an absolute hypofluorescence involving the whole optic disc. 15 eyes showed an absolute hypofluorescence limited to a part of the cup and the rim. 6 eyes showed a late hyperfluorescence of the fundus of the cup. Total hypofluorescence throughout all phases of fluorescein angiogram corresponds to filling defects. Absolute hypofluorescence involving the whole optic disc is associated with visual field loss in all cases. Absolute hypofluorescence involving only an area of the optic disc is associated with a normal visual field in a few cases. It is postulated that the limited filling defects without visual fields defects may be an indication of impending loss of the visual field. Therefore fluorescein angiography could be helpful in clinical assessment of visual prognosis of chronic ocular hypertension and glaucoma. Nevertheless wider experience and followup are necessary to confirm the value of the method.