| Category | Neuro Ophthalmology |
What is Optic Neuritis?
This is the most common cause of sudden visual loss in a young patient. It is often associated with discomfort in or around the eye, particularly with eye movement. The optic nerve fibers are coated with myelin to help them conduct the electrical signals back to your brain. In the most common form of optic neuritis, the optic nerve has been attacked by the body's overactive immune system. A viral infection that may have occurred years, or even decades, earlier may have set the stage for an acute episode of optic neuritis. The inflammation associated with optic neuritis can result in discomfort (particularly with the movement of the eye).
What are the symptoms of optic neuritis?
The most common symptom of optic neuritis is the sudden decrease in vision. In mild cases, it may look like "the contrast is turned down" or that colors appear "washed out." This may vary and, not infrequently, will progress from the time it is first noticed. The second most common symptom associated with optic neuritis is discomfort in or around the eye often made worse by the movement of the eye.
How does the Ophthalmologist know that I have optic neuritis?
A few patients with optic neuritis have swelling of the optic disc (the beginning of the optic nerve) at the back of the eye. This is referred to as papillitis. One sign usually detected by your eye doctor is the presence of an afferent pupillary defect. This indicates that there is less light being sensed by the affected eye than by the opposite eye. This is found by swinging a bright light back and forth between your two eyes while observing how your pupil reacts.
What will happen to the vision over time?
The pain will go away, usually in a few days. The vision problems will improve in the majority (92%) of patients. There are rare patients who have continued progressive loss of vision. Frequently colors look different or "washed out." Visual recovery usually takes place over a period of weeks to months, although both earlier and later improvement is possible. Optic neuritis can recur involving the same eye, the other eye, or other parts of the central nervous system (brain and spinal cord).
This may result in recurrent episodes of decreased or loss of vision or problems with weakness, numbness, or other signs of brain involvement. An MRI scan can give us a rough guess as to the likelihood of recurrence. Other testing techniques include visual evoked potentials (a test where you are shown a checkerboard of light and signals are recorded from electrodes on your scalp) that can show a delay in conduction due to the damage to the myelin.
How is optic neuritis treated?
Patients treated with oral (pills) steroids seem to have a higher chance of recurrent episodes. Therefore, steroid pills alone are not recommended as a treatment. Patients who were treated with intravenous (given by needle) steroids did have a slightly more rapid recovery of their vision, although the final visual outcome was not better than in those who were not treated. Thus, IV steroids can be recommended for patients with severe involvement or involvement of both eyes.
