Hypovolemic ischemic optic neuropathy

Ischemic optic neuropathy refers to an acute event of ischemia, or decreased blood flow, to the optic nerve resulting in varying degrees of vision loss and visual field defects. Typically this disease affects the elderly population who experience systemic diseases that compromise the blood flow efficiency of the optic nerve head (e.g., giant-cell arteritis, hypertension, diabetes, etc.). However, cases of blood loss to the optic nerve, secondary to traumatic injuries or surgeries, have also been shown to result in ischemic optic neuropathy, regardless of age. It seems that in these cases, the resulting anemia and hypotension play contributing roles in the development of ischemic optic neuropathy.

A 41-year-old black man came to us with optic nerve head pallor O.S., count-fingers vision O.S., positive afferent pupillary defect O.S., and a central scotoma O.S. after being hospitalized and treated for a stab wound to his left neck that severed his left carotid artery at the bifurcation.

This patient had been seen in the Optometry Clinic two years before the stab-wound incident. At that time, he had 20/20 vision in his left eye and no remarkable neurological deficits. His ocular presentation after the traumatic hypovolemic event was probably a direct result of the hypoperfusion to the left optic nerve head. This patient was diagnosed with a hypovolemic, or blood loss-related, ischemic optic neuropathy (O.S.).

Patients who experience large amounts of blood loss due to trauma, surgery, internal bleeding, etc. and report vision loss should be screened for possible optic nerve ischemia. As eye care providers, when we are presented with patients who have optic nerve head atrophy, we should inquire about events that may have precipitated blood loss, potentially triggering ischemic optic neuropathy.