ObjectiveTo investigate short-term changes in retinal and choroidal microcirculation in healthy adults after voluntary blood donation. MethodsA prospective observational clinical study. Nine healthy volunteers (18 eyes) who donated blood voluntarily at Tianjin Medical University Eye Hospital in August 2025 were included. Among them, 5 were male (10 eyes) and 4 were female (8 eyes); their age was (38.00±12.33) years old. Optical coherence tomography angiography was used to scan the macular area within a 6 mm×6 mm range. The software of the instrument automatically divided the scanning area into three concentric circular regions centered on the fovea centralis: the central fovea region with a diameter of 1 mm, the perifoveal central fovea region ranging from 1 to 3 mm, and the perifoveal area surrounding the fovea with a diameter of 3 to 6 mm. Measurements of blood flow density in the fovea centralis region, perifoveal central fovea region, and perifoveal area surrounding the fovea at different retinal layers (the entire retinal layer, the choroidal capillary layer, and the medium choroidal blood vessel layer) were conducted 30 minutes before blood donation and 30, 120 minutes after blood donation. Diastolic blood pressure (DBP), systolic blood pressure (SBP), and intraocular pressure were recorded, and ocular perfusion pressure (OPP) was calculated. Repeated measurement data were analyzed using one-way analysis of variance. ResultsThere was no statistically significant difference in SBP, DBP, OPP and intraocular pressure among different blood donors at different measurement time points (P＞0.05). There was also no statistically significant difference in SBP, DBP and intraocular pressure among overall blood donors at different time points (P＞0.05); however, OPP significantly decreased at 120 minutes after blood donation, and the difference was statistically significant (F=5.380, P=0.02). Compared with 30 minutes before blood donation, the temporal blood flow density in the periphery of the paracentral fovea, the superior part and the surrounding area of the fovea in the peripheral area decreased significantly at 30 minutes after blood donation (F=3.920, 3.45,0 4.200; P=0.03, 0.04, 0.02), and recovered by 120 minutes. There was no statistically significant difference in the blood flow density of the entire retinal layer in the macular area and the large blood vessel layer in the choroid at different measurement time points among overall blood donors (P＞0.05). The correlation analysis results showed that there was no significant correlation between OPP at 30 minutes and 120 minutes after blood donation and the temporal blood flow density of the choroidal capillary layer in the temporal part of the periphery of the paracentral fovea, the superior part and the surrounding area of the fovea (r=0.037, 0.047, 0.187, ?0.027, 0.056, 0.156; P＞0.05). ConclusionsThere is no significant correlation between the blood flow density in the macular area of the retina and choroid and OPP. The mild and reversible changes in the choroidal microcirculation could occur.
