What Are the Treatments for Ischemic Optic Neuropathy of the Retina?
Ischemic optic neuropathy refers to damage of the optic nerve due to a restriction in the blood supply of the optic nerve. It is characterized by a loss of vision over a period of a few days accompanied by a swelling of the optic disc. The loss of vision is usually permanent although some recovery is possible in the early stages with appropriate treatment.
Steroids may be helpful in treating the underlying conditions of ischemic optic neuropathy, such as giant cell arteritis but this will do little to recover the loss of vision. Accompanying conditions of ischemic optic neuropathy include high blood pressure and diabetes, which may also be treated medically.
A common steroid regimen consists of 40 to 60 milligrams per day (mg/d) of prednisone, depending on the patient. An initial dosage of 60 mg/d should be reduced by 10 mg every 2 weeks until it reaches 40 mg/d. This level should be maintained for two to four weeks and then reduced by an additional 5 mg/d every one to two weeks until it reaches 20 mg/d. From this point, reduce the daily dosage by 2.5 mg every one to two weeks until the dosage reaches 10 mg/d. The dosage of prednisone should then be tapered off by 1 mg per month until it is completely discontinued.
The course of ischemic optic neuropathy may be monitored by measuring the C-reactive protein (CRP) level and erythrocyte sedimentation rate (ESR) each month. The reduction schedule of the prednisone should be delayed if these tests show a recurrence of the disease. The dosage may even need to be increased slightly in the event of a flare-up.
Large dosages of steroids for the treatment of ischemic optic neuropathy are currently controversial. Some authors advocate intravenous doses of 1 gram daily for several days before continuing with standard dosages, although support for this treatment is currently lacking. Ongoing studies are attempting to determine whether large intravenous doses of steroids reduce the need for the long-term use of steroids in the treatment of ischemic optic neuropathy.
The traditional surgical treatment for anterior ischemic optic neuropathy has been fenestration (decompression) of the optic nerve although this treatment currently has few advocates. However, a biopsy of the temporal artery may be warranted to diagnose arteritis as the cause of the ischemic optic neuropathy.
The possible diagnosis of giant cell arteritis should involve a consultation with a rheumatologist. Giant cell arteritis can affect multiple systems and may also require consultations with other specialists.