The optic nerve is important because it has the job of sending visual information from the eyes to the brain. And yet, there are several disorders that can cause damage to this nerve for various reasons. Some hereditary diseases can damage the optic nerve. But so can certain enzyme deficiencies, vitamin deficiencies, inflammatory disorders and infections.
Leber’s Hereditary Optic Neuropathy
This is a rare disease. It is due to a mutation in the mitochondrial DNA, which means only a woman passes this mutation to all of her children. But for some unknown reason, it primarily affects males who are 11 to 30 years old, writes Paul Riordan-Eva, FRCS, consultant ophthalmologist at King’s College Hospital in “Vaughan & Asbury’s General Ophthalmology.” At first, people will have blurry vision in just one eye. But within a few days or months, they will have blurry vision in the other eye as well. Both optic nerves will eventually atrophy, or waste away.
Krabbe’s Disease
In this disease, children are born without enough galactocerebroside beta-galactosidase. This is an enzyme, or a protein, the body uses to speed up the amount of time that a process will take. Because children do not have enough of this enzyme, nerve tissue in the brain accumulates. Children will have seizures by the time they are 6 months old, as explained by Ramzi Cotran, M.D., professor of pathology at Harvard Medical School in “Robbins Pathologic Basis of Disease.” They usually have spasms, vomiting and decreased mental alertness. Before they are 1 year old, they become deaf and blind, as the optic nerve atrophies.
Dominant Optic Atrophy
In “The Merck Manual for Healthcare Professionals,” James Garrity, M.D., professor of ophthalmology at the Mayo Clinic writes about this disorder as being the most common hereditary optic nerve disease. One person out of every 10,000 to 50,000 people has this. By the time a child is 1 year old, the optic nerve has started to degenerate. The degeneration is very slow, but people will have vision loss in both of their eyes by the time they are older adults.
Optic Neuritis
Neuritis means "the inflammation of a nerve." In optic neuritis, the damage to the optic nerve is usually due to multiple sclerosis, according to Dr. Garrity in “The Merck Manual for Healthcare Professionals.” This disease may even be the first sign of multiple sclerosis. But tumors, tuberculosis, HIV, syphilis, meningitis, sinusitis, certain medications and chemicals can also cause this disorder.
Vitamin B12 Deficiency
The body uses vitamin B12, also known as cobalamin, to make and repair myelin, or the substance that surrounds the nerves so their signals travel faster. Vitamin B12 is also needed to make DNA and red blood cells. A deficiency of this vitamin leads to a problem with the nervous system and anemia. But it can also lead to optic nerve damage, according to Dr. Riordan-Eva in “Vaughan & Asbury’s General Ophthalmology.”
References
- “Robbins Pathologic Basis of Disease”; Ramzi Cotran, M.D., Vinay Kumar, M.D., Stanley Robbins, M.D.; 1994
- The Merck Manual for Healthcare Professionals: Hereditary Optic Neuropathies
- The Merck Manual for Healthcare Professionals: Optic Neuritis
- “Vaughan & Asbury’s General Ophthalmology”; Paul Riordan-Eva, FRCS, John Whitcher, M.D.; 2008
