Microcirculation in the conjunctiva and retina in healthy subjects

BACKGROUND: The aim was to determine the relationship between bulbar conjunctival microcirculation and retinal microcirculation in a healthy population. METHOD: A functional slit-lamp biomicroscope (FSLB) was used to measure blood flow velocity (BFV) and blood flow rate (BFR) in the conjunctiva while a retinal function imager (RFI) was used to measure macular BFV and BFR in the retina. One eye of each subject of 58 self-reported healthy subjects was imaged in the same session on the same day. RESULTS: The mean BFV in the venules of the conjunctiva was 0.49 ± 0.13 mm/s, which was significantly slower than that in the retinal arterioles (3.71 ± 0.78 mm/s, P < 0.001) and retinal venules (2.98 ± 0.58 mm/s, P < 0.001). The BFR in the conjunctiva (0.09 nl/s) was also significantly lower than that in the retina (arterioles = 0.81 nl/s, venules = 0.68 nl/s, all P < 0.001). The BFVs and BFRs were not related between the conjunctiva and retina (r ranged from − 0.17 to − 0.05, all P > 0.05). CONCLUSION: The microcirculation in the retina appeared to be different from that in the conjunctiva.