This is a video capture of an aqueous vein; a mixture of episcleral venous blood and aqueous humor mix in this combined channel. Aqueous humor drains as follows: through the trabecular meshwork into Schlemm's canal into external collector channels (deep scleral plexus) draining into the episcleral and conjuntival venous plexus.
The drainage in this system is valveless and depends on hydrostatics, note how the blink of the eye stops flow through the vein momentarily. If the flow was reversed by elevated episcleral venous pressure blood could be seen in Schlemm's canal by gonioscopy.
The video shows increasing levels of magnification to demonstrate individual red blood cells mixing with aqueous and laminar flow in the vein.
Reference: Clinical Pathways in Glaucoma. T. ZImmerman, K. Kooner, Published by Thieme. Copyright 2001. Pages 109-110.
Shield's Textbook of Glaucoma. R. Allingham, D. Damji, S. Freedman, et al. Lippincott Williams. Copyright 2005. Page 25.
Priluck, Joshua, M.D., Summa Health Systems, Akron, Ohio, United States