Neuro-visual disorders comprise a range of problems affecting the nerves in and around the eye.
Neuro-Visual Disorders: What You Need to Know
The ability to see is the result of an intricate system of communication between the eye, the optic nerves and the brain.
Problems affecting the nerves in and around the eye can result in several different conditions.
Prompt, accurate diagnosis is important for preserving vision and addressing symptoms.
Types of Neuro-Visual Disorders
Optic Nerve Disorders
Damage to the optic nerves can cause pain and vision problems, most commonly in just one eye. A person may notice vision loss in only the center of their field of vision (scotoma) or pain when they move the affected eye.
One type of optic neuropathy is optic neuritis, which can result from infections (such as chickenpox or influenza) or immune system disorders such as lupus.
Like other optic neuropathies, the main symptoms of optic neuritis are pain and vision disturbances. The doctor may recommend corticosteroids or other medications to address an overactive immune system if that is what is causing the nerve inflammation. Symptoms begin to improve within weeks or months, and most cases of optic neuritis resolve on their own completely within a year.
There is a relationship between this condition and multiple sclerosis (MS). Studies show that about half of people who develop optic neuritis will get MS in the following 15 years. For patients who have optic neuritis, the doctor may suggest an MRI to assess the person’s risk for getting MS. If this is the case, there are medicines that can help slow the progression or even prevent MS from occurring.
Giant Cell (Temporal) Arteritis
Giant cell arteritis (also called temporal arteritis) is an inflammation of medium-sized and large arteries that extend from the neck up into the head. The condition can affect a person’s vision in one eye. Other symptoms include a dry cough, fever, headache, jaw pain and problems with blood circulation in the arms. People with giant cell arteritis may be at risk for developing aneurysms.
When the doctor suspects giant cell arteritis, he or she will likely perform an exam and blood tests. If these tests show signs of the disease, the doctor may proceed with imaging studies, such as x-ray, ultrasound, MRI or PET scan, as well as a biopsy of one or both arteries in the temple area.
Treatment for giant cell arteritis includes a temporary course of steroid medications, including glucocorticoids, which can arrest the vision loss if started promptly. These medications may have side effects, so it is important to communicate with the doctor to understand risks and benefits.
The optic chiasm is the crossing of the optic nerves of the right and left eyes where half of the nerve fibers from each eye cross to the other side, enabling a person to use both eyes to focus, perceive depth and maintain a normal field of vision.
Problems with blood vessels in the brain, including bleeding, are the most common cause of problems in the optic chiasm, but tumors and trauma can also result in chiasm disorders.
The symptoms can be disabling, affecting the person’s ability to read and visually scan and navigate the world around them. They may not notice approaching vehicles or people, and this may result in a loss of the ability to drive.
Treatment involves addressing the underlying cause of a chiasm disorder.
Eye Movement Disorders
Nerve problems can affect the nerves of the muscles surrounding the eyeball and those that control the dilation and contraction of the pupil. Such problems can result in symptoms such as double vision, nystagmus, oscillopsia and disorders of the pupils, such as anisocoria.
The doctor is likely to evaluate a person with these problems carefully, particularly if the symptoms are new, because they can indicate a serious problem such as multiple sclerosis, head trauma, aneurysm or tumor.
Temporary Vision Problems
Transient vision problems can be related to auras, a symptom of migraine and other headaches. In the aura phase, a person can experience visual, sensory or motor symptoms that can precede the headache. Examples include vision changes, hallucinations, numbness, changes in speech and muscle weakness. A doctor can evaluate a person’s symptoms and help determine a cause. In many cases, migraine treatment can address auras.