Assessment of chorioretinal blood flow and vessel diameter by laser speckle flowgraphy in three animal models

Abstract

PurposeTo investigate the differences in optic nerve head (ONH) blood flow and retinal vessel diameter measured by laser speckle flowgraphy (LSFG) in C57 BL/6 (wild type) mouse, Akita (diabetic) mouse, and wild‐type monkey models.MethodsLSFG measurements of mean blur rate (MBR), relative flow volume (RFV) and vessel diameter were obtained in 20 C57 BL/6 mice, 10 Akita mice and 8 wild‐type monkeys. Comparisons of the three measurements were made between C57 BL/6 and Akita mouse models, and between C57 BL/6 mouse and monkey models using Student's t‐test.ResultsRFV which measures retinal blood flow, was significantly reduced in one of the retinal veins (V4, p = 0.004) as well as globally (p = 0.04) in Akita mice compared to C57 BL/6 mice. There were no significant differences in MBR which is a measure of ONH choioretinal blood flow, or retinal vein diameter between C57 BL/6 and Akita mice. In monkeys, we noted significantly increased MBR (p < 0.001) compared to C57 BL/6 mice. There were also increased RFV and vein diameter in two of the retinal veins (V4 and V6) as well as globally in monkeys.ConclusionsDiabetic mice had compromised retinal blood flow while maintained similar level of ONH total choroiretinal blood flow compared to wild type mice. This may indicate retinal vessels are more affected by diabetes compared to choroidal vessels. Our data also suggest that ONH total and retinal blood flow and retinal vein diameter were increased in big monkey model compared to small mouse models.