Optic nerve drusen (also known as optic disc drusen) are abnormal deposits of protein-like material in the optic disc-the front part of the optic nerve. These drusen are made up of protein and calcium salts and generally appear in both eyes. Optic nerve drusen may be inherited or may occur without any family history. Familial drusen are inherited as an autosomal dominant trait, which means your mother or father or child is likely to have the condition.
Optic nerve drusen are not related to aging and often appear in children. They don’t affect vision, but some patients with these drusen may lose peripheral (side) vision. The average age when optic disc drusen first appear is about 12. Often, the optic disc has an unusual appearance, with multiple branches of the major blood vessels as they emerge on the disc. Overtime, optic nerve drusen can become more prominent.
Symptoms of Optic nerve drusen
Optic nerve drusen is often detected during a routine eye examination. Patients usually have no symptoms and do not notice any changes in their vision. Sporadically, patients may have flickering or greying out of vision that lasts a few seconds or they may notice subtle visual field loss. The elevation of the optic disc with drusen may be mistaken for papilledema, which is swelling of the optic nerve from increased intracranial pressure. This prompts referral to a neurologist.
Diagnosis of Optic nerve drusen
If the drusen are on the surface of the optic nerve they can be easily seen and no special management is needed for their diagnosis. When they are deeper the optic nerve may appear ‘swollen’ but the drusen can be seen with an ultrasound examination. A visual field analysis is done to detect any peripheral visual field changes. If the drusen have become calcified, they also can be detected with computer tomography (CT) scanning.
Prognosis of Optic nerve drusen
Most patients with optic disc drusen retain normal central vision. However, over time ¾ of patients lose some peripheral vision. The amount of peripheral visual field loss varies from none to severe constriction of the peripheral visual field. The visual field should be followed periodically with formal visual fields testing. Patients with optic disc drusen may also be at an increased risk for developing nonarteritic anterior ischemic optic neuropathy, branch retinal vein occlusion and central retinal vein occlusion.
Treatment of Optic nerve drusen
There is no proven treatment for optic disc drusen. Sometimes it may be beneficial to monitor the visual fields and offer treatment to help with the blood-flow to the optic nerve if there are field changes. Rarely a small area of new blood vessels can develop next to the optic disc. This can lead to a sudden drop in vision. If any distortion of vision occurs, you should consult an ophthalmologist on an urgent basis as early treatment may help keep good vision.