The blood volume of the rabbit eye measured by use of erythrocytes tagged with radioactive iron (59Fe) is extremely small, 18.2μl. The hematocrit of the eye is approximately one half that of venous blood and is consistent with the rheologic behavior of blood in the ocular microvasculature. Utilizing iodinated I 131 serum albumin (human), an apparent progressive increase in the ocular albumin was noted. This finding, due to an increase in the eye/plasma 131I-albumin ratio during the time of the study, negates the use of this substance for determination of ocular plasma volume.
Fish MB, Aronson SB, Pollycove M, Coon MA. Ocular Blood Volume. Arch Ophthalmol. 1969;82(3):377-380. doi:10.1001/archopht.1969.00990020379016