ObjectiveTo observe the retinal microcirculation changes in chinchilla rabbit with branch retinal vein occlusion (BRVO), and to evaluate the feasibility of laser speckle imaging (LSI) technology as monitoring tool for retinal microcirculation. MethodsTen 4-month-old chinchilla rabbits were used for the experiment, selecting the right eye as the experimental eye. The main retinal vein, adjacent 0.5-1.0 mm to the optic of rabbit retina, was selected to the target vessel under surgical microscope. The software of LSI instrument was used to measure the diameter of target vein and blood flow of 0.2 mm2 area of target vein. The BRVO rabbit model was induced by photodynamic therapy, then measure the diameter and blood flow in the same region using the method as before and after 10 minutes modeled. ResultsThe retinal color pictures, infrared laser and the distribution of blood flow pseudo-color were synchronous displayed by LSI technology. Before and after modeling, the target vessel diameter were (0.104±0.009), (0.128±0.008) mm, and the 0.2 mm2 area blood flow of target vessel were (563.500±28.788), (256.000±53.319) PU. The diameter of target blood vessel after modeling was significantly thicker than before, with the significant difference (t=12.14,P=0.008). The blood flow in 0.2 mm2 area of target vessel was significantly lower than before, also with the significant difference (t=183.00,P=0.009). ConclusionsThe diameter of target vessel of the BRVO rabbit model is enlarged, and the target vessel area of 0.2 mm2 blood flow is reduced significantly. LSI system can monitor the retinal microcirculation real-time and quantitatively.