Optic Nerve Drusen
Have you been told by your eye doctor that you have optic disc drusen or optic nerve drusen? For most patients, the first time they hear this term is from their doctor because, in the vast majority of cases, patients tend to have no symptoms. Optic nerve drusen is usually found incidentally on a dilated eye exam done by an ophthalmologist or optometrist.
On exam, your optic nerve may have blurry margins but this blurring is not concerning for a more serious problem called optic disc edema. If you have optic nerve drusen in one eye, then you are very likely to have it in the other. In fact, the finding is bilateral in about 75% of patients.
Optic nerve drusen are small, calcified deposits that can form within the optic nerve. The optic nerve is also known as Cranial Nerve 2 and it sends visual messages from the eyeball to the brain. These deposits are typically benign and do not cause any symptoms, but in rare cases, they can cause vision loss or other problems.
The exact cause of optic nerve drusen is not well understood, but they are thought to be related to a genetic predisposition. They are usually present at birth and diagnosed during a routine eye exam later in life.
Optic Nerve Drusen Symptoms
The majority of patients will have no symptoms. In some patients, they may report the vision being dim. In medical terminology this is sometimes called a transient visual obscuration, and it happens in less than 9% of patients. Patients may also have visual field defect, but this is typically only found on visual field testing, and is not a symptom that patients come in complaining of. The visual field defect can be seen on formal visual field testing done in the eye doctor’s office. Visual field defects are more common than having a symptom of dim vision and it is seen in anywhere from 30% to 70% of patients. This is why it is important to see your ophthalmologist regularly if you have optic nerve drusen.
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Treating Optic Nerve Drusen
There is no treatment for optic nerve drusen. Because these findings are deeply embedded into the optic nerve, it is not possible to treat them or remove them. For the vast majority of patients drusen of the optic nerve does not cause any visual issues. The most compelling reason to monitor them is to see if they are having an effect on the vision. If the patient has another superimposing optic nerve disease such as optic neuritis or glaucoma, it is a good idea to have a baseline assessment of how the drusen has affected the vision, if at all. The way to monitor this is by having a patient do a visual field in the office. Depending on the baseline visual field or the appearance of the optic nerve, an ophthalmologist will typically want to do this once or twice a year.
Sources:
Hamann S, Malmqvist L, Costello F. Optic disc drusen: understanding an old problem from a new perspective.Acta Ophthalmol. 2018;96(7):673-684. doi:10.1111/aos.13748
