Computerized image analysis was used to measure changes in percent area of pallor of the optic disc in a retrospective study of a group of 16 normals and 39 untreated ocular hypertensives. The optic discs of the subjects were photographed on at least two visits at least one year apart (mean, 2 years). No significant changes in area of pallor for the normal group were observed between visits, except in the inferior quadrant of the left eye. The ocular hypertensive group showed a significant increase in area of pallor between visits for the total disc and for most quadrants of both eyes. Multiple regression analysis revealed that, in addition to ocular hypertension, the significant factors associated with a change in optic disc pallor were change of ocular pressure, standard deviation of the ocular pressures, presence of vascular hypertension, and standard deviation of vascular pulse pressures. Clinical implications of early detection of disc changes for follow-up and treatment of ocular hypertensives are discussed.