Macular microcirculation and macular oedema in branch retinal vein occlusion.

Abstract

The relationship between the blood-flow velocity in the perifoveal capillaries and macular oedema was investigated in patients with branch retinal vein occlusion (BRVO). This study compared 18 patients with BRVO and 16 healthy volunteers. Perifoveal capillary blood-flow velocity was measured on fluorescein angiograms with a scanning laser ophthalmoscope by the tracing method. Retinal thickness at the central fovea was measured by optical coherence tomography. Then, the relation between perifoveal capillary blood-flow velocity and retinal thickness at the central fovea was investigated. Perifoveal capillary blood-flow velocity was significantly lower in the patients with BRVO (1.08 (SD 0.28) mm/s) than in the healthy volunteers (1.49 (0.11) mm/s) (p<0.0001). Capillary blood-flow velocity showed a negative correlation with the retinal thickness at the central fovea in the two groups (r = -0.8426, p<0.0001). Multivariate linear regression analysis with stepwise variable selection confirmed that capillary blood-flow velocity was an independent determinant of the retinal thickness at the central fovea (p<0.001). A reduction in perifoveal capillary blood-flow velocity may be involved in the development of macular oedema in patients with BRVO.