An ischemic optic neuropathy (ION) represents a stroke of the optic nerve. Vision loss may be mild or may be severe in the affected eye.
Different subtypes of ION exist:
1. Nonarteritic IONs tends to affect patients in their late 40s and in their 50s. These patients often have high blood pressure, high cholesterol, and/or diabetes.
2. Arteritic IONs can affect patients in their 60s and older. Arteritic IONs represent a “vasculitis;” the blood vessels supplying the optic nerve are inflamed. Blood vessels elsewhere in the body (brain, muscles, bowels) may be inflamed as well. Patients may present with headache, temporal tenderness, pain with brushing or combing the hair, jaw ache, chewing fatigue, muscle ache, and generally not feeling good.
Arteritic IONs constitute an ophthalmic and medical emergency. The patient must be treated immediately with high dose steroids. A biopsy of a blood vessel under the temporal forehead skin may be recommended.
3. Hypoperfusion ION or “shock optic neuropathy” may occur if blood pressure dips severely after severe blood loss associated with an accident, gastrointestinal bleeding, or major surgery. The optic nerve experiences several minutes of reduced blood flow and reduced oxygen and suffers an infarction.
If Dr. Dahr thinks an ION is a potential cause of your vision loss, he will refer you to an ophthalmologist who specializes in the optic nerve (a “neuro-ophthalmologist”) for additional evaluation and treatment.
Information from Professor Hayreh of the University of Iowa regarding ION. Professor Hayreh is the world’s expert on the microvascular anatomy of the optic nerve.