“…According to von Haller (1781), this crossing is either gradual or abrupt. The fact that the ophthalmic artery quite often crosses under the optic nerve has been noted by many workers (Mayer, 1777;Zinn, 1780;von Haller, 1781;Blandin, 1834;Theile, 1841;Sommerring, 1841;Arnold, 1847;Luschka, 1865;Zuckerkandl, 1876;Meyer, 1887;Quain, 1892;Adachi, 1928;Sudakevitch, 1947;Wolff, 1954;Hayreh, 1958;Hayreh and Dass, 1959;Singh and Dass, 1960). Table I (opposite) shows that the actual incidence of crossing under the optic nerve is very variously described by various authors.…”