In order to investigate an association between systemic blood pressure and restitution of normal visual function in dim illumination after photostress, macular recovery time and blood pressure were measured in two groups: 1) 90 young and healthy military pilots and applicants for military pilot training; and 2) 10 hypertensive patients before and after 12 weeks of antihypertensive treatment. Young normotensive subjects (20/20 vision) with low diastolic blood pressure performed less well (longer macular recovery time) than those with higher pressure (r = -0.42, p less than or equal to 0.05). Among the hypertensive patients three were given doxazosin, three, prazosin, and four, placebo. The treatment period produced significant fall in blood pressures, a small reduction in intraocular pressure (p less than or equal to 0.03) and a lengthening of initial monocular recovery period (p = 0.04) in addition to reduced monocular (p = 0.015) and binocular (p = 0.022) macular recovery in the remaining part of the 2-min test period. This observation may be important for antihypertensive treated patients whose occupation requires fast visual adjustment to changing stimuli in dim light.