Comparative extraocular muscle blood flow.

This study was designed to quantitatively determine blood flow to the extraocular muscles (EOM) of animals showing a wide range of ocular motility. Blood-flow values (ml/minute/gm) for EOM in primates (0.25 ± 0.03), dogs (0.33 ± 0.06), sheep (0.12 ± 0.01), and geese (0.12 ± 0.04) were determined using the Reference Sample Method with 15 ± 3 μm 103Ru microspheres and complete cardiovascular monitoring. Mammalian EOM blood flow was significantly higher than that determined for other skeletal muscle; however, EOM blood-flow values for sheep were significantly lower than those for primates and dogs. No significant blood-flow differences were found between avian EOM and other skeletal muscle, reflecting the unique avian ocular anatomy. These data indicate that high blood flow is not a general property of EOM and suggest a relationship between functional ocular motility and blood flow.