Journal of Neuro-Ophthalmology, December 1998, Volume 18, Issue 4

Proptosis with Acute Oculomotor and Abducens Nerve Palsies

OBJECTIVE: To determine whether orbital axial proptosis occurs in the affected eye of patients with acute oculomotor or abducens nerve palsy. MATERIALS AND METHODS: In this prospective, cross-sectional survey, the Hertel instrument was used to measure the amount of axial protrusion in 26 consecutive patients with complete or severe acute oculomotor nerve palsy and 27 consecutive patients with complete or severe acute abducens nerve palsy. The Mann-Whitney test was used to compare the amount of relative proptosis of the affected eye in the patient groups with that of 40 control subjects. The absolute amount of the interocular difference in axial protrusion of the normal eyes was used to determine control values. The proportion of patients and control subjects with relative proptosis greater than 1 mm was compared using Fisher's exact test. RESULTS: There was no significant difference in the degree of relative proptosis of the affected eye of patients with oculomotor nerve palsy or abducens nerve palsy as compared with the control eyes. Likewise, there was no significant difference in the proportion of patients with relative proptosis greater than 1 mm in either the oculomotor nerve palsy group or the abducens nerve palsy group as compared with the control group. CONCLUSIONS: Acute oculomotor or abducens nerve palsy does not produce any significant amount of orbital axial proptosis in the affected eye, at least as measured clinically using the Hertel instrument. Acute neurogenic ophthalmoplegia rarely causes relative proptosis greater than 1 mm.