Figure 1.

Axial (left column) and quasicoronal (right column) MRI of both orbits in a patient with advanced POAG with IOP never exceeding the normal range, imaged in maximal dextorversion (top row), moderate dextroversion (second row), cental gaze (center row), moderate levoversion (fourth row), and maximal levoversion (bottom row). The optic nerve (ON) of each eye straightened in moderate adduction and remained straight in maximal adduction, while it was sinuous in abduction. Coronal views taken just posterior to the globe-ON junction demonstrate that the ON within its sheath is surrounded by a bright ring of cerebrospinal fluid, but the ON shifts to the temporal side of the sheath in adduction. Both ON cross sections are subnormal due to glaucomatous atrophy, but a focal area of atrophy is also evident in the inferior ON cross section of the left eye. IR, inferior rectus muscle; LPS, levator palpebrae superioris muscle; LR, lateral rectus muscle; MR, medial rectus muscle; SR, superior rectus muscles.