Drusen are deposits which can appear in the choroid of the eye, in an area known as Bruch's membrane, or around the optic nerve. The development of drusen appears to be a natural byproduct of aging, but sometimes these deposits can be associated with vision problems. They are usually identified during a routine eye exam in which they can be seen by a doctor, and additional diagnostic testing such as ultrasound or other medical imaging studies of the eye and head can be used to learn more about the precise location and size of the deposit.
The mechanism behind the formation of drusen is not understood. They may be deposits left behind by the immune system, or they may be associated with natural processes inside the eye. They range in color from white to creamy yellow, and have a glittering appearance which inspired the name— “drusen” is German for “geode.”They can vary widely in size and shape, often appearing disc-like when they are magnified.
Drusen in the choroid are different from deposits around the optic nerve. In the case of deposits around the choroid, many people naturally have them as they grow older. In some cases, they can be associated with macular degeneration. Whether the deposits cause or are simply linked with the degeneration of the macula is not known. The development of drusen in younger patients or the rapid growth of these deposits can be a cause for concern, as it may indicate that abnormalities are occurring inside the eye.
When these formations develop along the optic nerve, over time, they will slowly compress the nerve. This can cause distortions in the visual field, especially around the edges, and may even cause blindness. There are some other rare complications including bleeding in the eye which can emerge in patients with optic nerve drusen.
There is no cure for these deposits. Treatment is focused on managing them and monitoring patients for any signs of changes. Drusen can occasionally be associated with other complications, making it important to receive regular eye exams to keep an eye on the condition. Patients should also make sure to obtain a copy of their chart if they need to switch doctors so that the new doctor can read the notes on when the deposits were first noticed and how they have changed since the initial diagnosis. This information can be extremely useful for management of the patient's condition.