In 1941, for the first time by means of the biomicroscope, aqueous humor was seen to stream thorough conjunctival and episcleral veins of the normal human eye. Vessels containing a clear fluid, sometimes mixed with varying amounts of blood, can be found in at least one third of all quiet human eyes with the use of the corneal microscope and slit lamp illumination. . . .
Many ophthalmologists have had difficulty in recognizing the aqueous veins, whereas others have confirmed their occurrence and significance. Photographs of recipient vessels have corroborated the presence of highly diluted blood in these vessels, as well as the influence of drugs on the elimination of intraocular fluid through the aqueous veins.
A look at the past . . .. Arch Ophthalmol. 2008;126(7):905. doi:10.1001/archopht.126.7.905