Optic nerve drusen are abnormal globular collections of protein and calcium salts which accumulate in the optic nerve and usually become visible after the first decade of life. They occur in both eyes more often than just one [See figures 1 and 2].
The appearance of the optic disc may be sufficient to make the diagnosis. Ocular ultrasound, CT scan and/or fundus photography can aid in the diagnosis. Drusen can be inherited, so it may be helpful to examine other family members. .
Optic nerve drusen usually do not affect vision. However, peripheral vision loss may occur slowly and be so minimal that the abnormality is never noticed. Less commonly there may be an abrupt, painless loss of part of the peripheral vision. A rare complication from optic nerve drusen is choroidal neovascular membrane, an abnormal blood vessel that grows beneath the retina near the optic nerve. This can cause a sudden decrease in central or “straight ahead” vision.
Drusen on the surface of the optic disc can mimic a more serious abnormality, papilledema (swelling from elevated pressure in the brain). It is important to be aware of drusen so that unnecessary tests for papilledema are not performed.
In many individuals, particularly children, drusen are not visible on the optic disc surface but are instead buried deeper within the nerve tissue. The optic disc appears swollen despite the drusen not being visible on the surface. As the drusen enlarge and the overlying tissue (nerve fiber layer) thins with age, the disc drusen become more apparent.
There is no treatment for drusen. In the rare cases (with choroidal neovascularization) laser treatment may be indicated.
Revised November, 2012
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