Dr Ben Wild
Overview |
Our vision comes from light waves stimulating retinal photoreceptors and these photoreceptors transferring their signals through a multitude of other cells to the ganglion nerve cells. These ganglion cells bunch together and form the optic nerve. The optic nerve then sends the signal to the occipital lobe in the brain where vision is interpreted and recognized.
An image of a healthy retina and optic nerve.
Optic disk drusen are small calcified deposits that grow in the optic nerve. They occur in about 2% of people and 75% of the time are found in both eyes. Optic disc drusen are genetically inherited. Over time, these calcium deposits can grow and cut off the parts of the signal that goes from the optic nerve to the brain thus causing blind spots in 75% of cases. This condition has been known to correlate with higher chances of choroidal neovascularization (growth of small blood vessel networks), vein or artery occlusions, anterior ischemic optic neuropathy (inflammation of the optic nerve).
An image of a healthy retina and optic disk drusen.
Signs and Symptoms |
Signs
Blood vessels exiting the nerve are tortuous (wiggly), the nerve is lumpy and full, there may be more blood vessels exiting the nerve than normal, off-white lumps of calcium on the nerve that become easier to see during an eye exam with increased age.
Symptoms
Usually none, small blind spots may develop, on rare occasions, there may be episodes of blurry vision thought to be caused by decreased oxygen transfer to the optic nerve.
Causes and Risk Factors |
Causes
Genetically inherited in an autosomal dominant manner (only 1 copy of the trait is required).
Risk Factors
No known risk factors.
Prevention and Treatment |
Prevention
There are no known preventative measures.
Treatments
There are no current treatments for optic nerve drusen but treatments are required for the conditions that are correlated with optic nerve drusen.
· Intra-vitreal anti-VEGF injections for choroidal neovascularization (growth of small blood vessel networks).
· Vitrectomy if there is a complicated blood vessel leak into the eye.
· Glaucoma drops to decrease the chance of a second anterior ischemic optic neuropathy episode.
Prognosis |
Optic nerve drusen are quite common and in most cases do cause blind spots that slowly enlarge over time, much like those seen in glaucoma. Unfortunately, there currently are no treatments. Thankfully, unless complicated by one of the above secondary issues, this condition does not cause substantial vision loss and does not cause any discomfort.
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