A prospective study was designed to determine the course of ocular hypertension without visual field loss if untreated and to estimate the value of various clinical findings in prediction the course of ocular hypertension. Seventy-five patients with intraocular pressure greater than 21 mm Hg but without demonstrable visual field defects were followed up without glaucoma therapy for a minimum of nine years. While under observation, seven of 75 ocular hypertensives developed typical glaucomatous visual field defects. Both the sensitivity and the specificity of each clinical finding in the individuals who later developed visual field defects were determined, and none of the clinical findings was found to be a good predictive indicator.