Twenty-seven patients (ages 13-55 years) with Takayasu's arteritis (TA) underwent a detailed ophthalmological examination which included a history of visual symptoms, recording of visual acuity, slit-lamp examination, examination of retina (direct fundoscopy and rapid sequence fluorescein angiography) and estimation of retinal haemodynamics. Arterial hypertension was the commonest (77%) presentation of TA. Sixty-six percent of the patients had one or more ocular change. Sixteen (33%) of the 54 eyes tested had Takayasu's retinopathy (TR), 20 eyes (37%) had hypertensive retinopathy (HR) and the retina was normal (NR) in 18 eyes (33%). Two patients with advanced TR had bilateral cataract. The arm-to-retina circulation time in eyes with TR (16.4 +/- 2.66 seconds) was prolonged as compared to the eyes with HR (10.9 +/- 1.63 seconds, P < 0.01) and NR (9.6 +/- 2.37 seconds, P < 0.01). The arteriovenous filling time in eyes with TR was also significantly prolonged. The intraocular pressure (mmHg) in eyes with TR (9.3 +/- 3.6) was lower (P < 0.001) than that in eyes with HR (14.4 +/- 4.1 mmHg) and NR (14.2 +/- 2.6). Central retinal artery pressure recorded in 8 eyes with TR was less than 35 mmHg in spite of the systemic hypertension. The retinal haemodynamics suggest that the carotid artery involvement leading to diminished retinal blood flow is the pathogenetic mechanism of TR.