OCT angiography model eye by use of the Brownian motion without flowing liquids

We propose a model eye for OCT angiography (OCT-A) with a retinal phantom without using any liquid flow. Instead of the flow, this phantom actively uses the particle movement caused by Brownian motion. The magnitude of the particle movement depends on particle size and liquid viscosity. We used much smaller particles of 150 to 250nm than erythrocytes so that Brownian motion generates sufficient particle displacement in OCT-A interscan duration. We controlled the liquid viscosity by changing the mixture ratio. The liquids were sealed in the phantom channels which having 100μm in height and 40 or 60μm in width. The OCT-A signals were successfully obtained at the particle-distributed liquids in the phantom channels. The obtained OCT-A signals became larger at lower viscosity liquid and were comparable to those at the human-eye fundus vessels. The proposed technique using Brownian motion in sealed liquid is promising to constitute the model eye that widely operatable in imaging validation without flow control and system maintenance.