Retinal blood flow and systemic blood pressure in health young subjects

Background: The aim of the present study was to investigate the association between systemic blood pressure and retinal blood flow in healthy young subjects. Methods: Three independent study cohorts were included. A cross-sectional study was performed in 420 young male subjects with systolic blood pressure less than or equal to 160 mmHg and diastolic blood pressure less than or equal to 100 mmHg. Retinal white blood cell flux (n=210) and blood velocity in the central retinal artery (n=210) were measured. In addition, a longitudinal study was performed in 40 young male subjects in whom retinal and systemic haemodynamic parameters were measured thrice within 6 weeks. Retinal white blood cell flux was measured with the blue-field entoptic technique. Blood flow velocity in the central retinal artery was measured by means of colour Doppler imaging. Results: Retinal white blood cell flux (r=0.262; P <0.001) and mean flow velocity in the central retinal artery (r=0.174, P=0.010) were significantly associated with mean arterial pressure in the cross-sectional study. In the longitudinal study retinal white blood cell flux and mean flow velocity in the central retinal artery were also correlated with systemic blood pressure. Conclusions: Our data indicate a slight but significant increase in retinal blood flow with blood pressure. Whether this is of clinical relevance in eye diseases with altered retinal perfusion, such as diabetic retinopathy, remains to be established.