About Ischemic Optic Neuropathy (ION)
The optic nerve is a bundle of nerve fibers that transmit visual information from your retina to your brain. In order to function properly, the optic nerve requires blood supplied from a system of arteries. When this blood flow is interrupted, patients can experience vision loss in one or both eyes. This loss of vision is painless but may occur very suddenly. Damage to the optic nerve cannot be fixed and vision loss as a result of ION is usually permanent, making the condition an ophthalmic emergency that requires immediate evaluation and treatment.
Types of Ischemic Optic Neuropathy
The different forms of ION are distinguished by the region of the optic nerve that is affected as well as the presence of arterial inflammation.
- Anterior ischemic optic neuropathy (AION): ION affects the head of the optic nerve
- Arteritic anterior ischemic optic neuropathy (A-AION): AION is caused by arterial inflammation
- Non-arteritic anterior ischemic optic neuropathy (NA-AION): AION without arterial inflammation
- Posterior ischemic optic neuropathy (PION): ION affecting the rest of the optic nerve, typically occurs after major surgeries, such as neurosurgical or cardiothoracic procedures
Anterior ION is much more common than posterior forms of the condition. Similarly, non-arteritic subtypes of ION are far more common and occur in patients 50 and older, while arteritic ION appears much less frequently and typically in patients aged 70 and above.
Symptoms of Ischemic Optic Neuropathy
The main symptom of any form of ischemic optic neuropathy is a painless loss or blurring of vision in one or both eyes. ION can affect both central vision and peripheral vision.
An early symptom of the condition may be darkened vision that persists for a few seconds or minutes before returning to normal.
Risk Factors for Ischemic Optic Neuropathy
Ischemic optic neuropathy can affect anybody, but certain factors may increase the likelihood of condition onset. As ION involves a disruption of blood flow to the optic nerve, many of these factors are related to vascular function.
Risk factors for ischemic optic neuropathy may include:
- Being 50 years or older
- A history of diabetes
- A history of temporal arteritis, or swelling of the arteries in the head
- A history of hypertension
- A history of hyperlipidemia
- A history of sleep apnea
- A sudden drop in blood pressure
- A history of sleep apnea
- High cholesterol
- A history of vasculitis
In rare instances, ION can present as a complication of certain surgeries.
Treating Ischemic Optic Neuropathy at UT Health Austin
A careful eye exam and visual field exam may be used to determine the underlying cause of ischemic optic neuropathy. Treatment depends on the cause of the ischemic optic neuropathy and your healthcare provider will work with you on determining the best course of action. Your ophthalmologist is well-versed in the most current, evidence-based treatment recommendations, which may include monitoring or medications.
Care Team Approach
At UT Health Austin, we take a multidisciplinary approach to your care. This means you will benefit from the expertise of multiple specialists across a variety of disciplines. Your care team will include fellowship-trained neuro-ophthalmologists, ophthalmic technicians, physician assistants, nurse practitioners, social workers, and more who work together to help you get back to the things in your life that matter most to you. We also collaborate with our colleagues at the Dell Medical School and The University of Texas at Austin to utilize the latest research, diagnostic, and treatment techniques, allowing us to identify new therapies to improve treatment outcomes. We are committed to communicating and coordinating your care with your other healthcare providers to ensure that we are providing you with comprehensive, whole-person care.