Oliver Backhouse, Consultant Eye Surgeon www.cataract.org.uk
Optic Disc Drusen are protein like deposits in the Optic nerve (the cable that takes the message from the eye to the brain). The exact cause is not known but they are thought to be from ‘abnormal’ flow of material in the optic nerve cells.
These drusen are present in approximately 1% of the white population and can sometimes run in families though they usually occur spontaneously. Most people will have the drusen in both eyes. They are not visible at birth and rarely seen in infants and children. They become more visible with age as they come to the surface of the Optic nerve and acquire calcium. This can give a lumpy appearance to the Optic Nerve and be associated with multiple branches of the major blood vessels as they emerge on the top of the Optic Nerve. They are rarely associated with other eye or systemic diseases.
Optic Disc Drusen are usually first seen on a routine visit to the Optician and the patient has no symptoms. Occasionally, patients may have flickering or graying out of vision that lasts a few seconds or there can be subtle visual field changes. The full ‘swollen’ appearance of the Optic nerve can easily be mistaken for Optic nerve swelling due to raised pressure inside the head (papilloedema) and therefore there may be an urgent request for the patient to be seen in the Ophthalmology or Neurology department.
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.
Most people keep good central vision and do not notice any change. Detailed visual field testing can pick up subtle changes of peripheral vision in 70% of people over time. There is also a slight increase in the risk of non-arteritic ischaemic optic neuropathy
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 (choroidal neovascular membrane) can develop next to the optic disc. This can cause a sudden drop in vision. Should any distortion of vision occur, you should consult an Ophthalmologist on an urgent basis as early treatment may help keep good vision.
Disclaimer: Adapted from Nanos.