Some ocular diseases lead to temporary changes in the ocular blood circulation. This study was undertaken to evaluate changes in the blood-flow velocity of the ophthalmic artery in patients with endophthalmitis. With pulsed Doppler sonography the blood velocity of the ophthalmic artery was measured in 50 normal subjects and in ten patients with bacterial endophthalmitis. In normal subjects blood velocity decreased with increasing age, and the average systolic/diastolic blood velocity in cm/sec were 38.8 +/- 6.3/11.6 +/- 4.7 in the 18-50-year-old age group and 28.3 +/- 4.6/6.7 +/- 3.3 in the 51-88-year-old age group. Endophthalmitis produced increased systolic/diastolic blood velocity in the ophthalmic artery in the affected eyes in cm/sec (99.7 +/- 15.5/26.6 +/- 10.5 in the 16-50-year-old age group; 60.4 +/- 8.8/16.6 +/- 4.8 in the 51-83-year-old age group). Some patients showed similar changes in the unaffected fellow eyes. The noted elevation of the blood velocity in unaffected eyes may be due to the bilaterally projected parasympathetic fibers of the oculomotor nerve.