When blood supply is cut off to the area, the optic nerve will be harmed causing an optic neuropathy. Other causes may include deficiencies in vitamins and exposure to hazardous materials.
When the blood supply to the optic nerve is impeded, the optic nerve cells will cease to function. Or if they do continue to function, they will do so abnormally. This is referred to as an ischemic optic neuropathy. This optic nerve neuropathy is divided into two types. Nonarteritic ischemic optic neuropathies usually affect people above the age of fifty, who are hypertensive, diabetic, and have atherosclerosis. Arteritic ischemic optic neuropathies are seen in people over seventy years old. Blood supply to the optic nerve is hindered because of the inflammation of the arteries, known as arteritis. The temporal artery is the most common artery that becomes affected, causing temporal arteritis. An acute inflammation of the optic nerve — or retrobulbar optic neuritis — is usually seen in patients with multiple sclerosis.
The optic nerve can also be injured by being exposed to toxic substances such as lead, methanol, ethylene glycol, tobacco, or arsenic. Both eyes are affected in this optic neuropathy, wherein vision loss starts at the middle of the visual field and slowly progresses to complete blindness. Nutritional deficiencies, specifically B vitamin deficiencies, can also produce a neuropathy. The treatment for this kind of optic neuropathy is to manage the underlying cause, which is malnutrition, by taking vitamin supplements as well as implementing a well-balanced diet.
Another optic neuropathy that usually affects only men in their late twenties or early thirties is Leber’s optic neuropathy. It is a rare condition in which central vision is lost. At first, one eye is affected, and then a couple of months later, the second eye is also affected. Leber’s optic neuropathy is a genetic condition, thus also the name Leber’s hereditary optic neuropathy. It is a sex dominant genetic illness wherein the female or the mother is the one responsible for passing it on to her children, since it is found in the egg cell. Men cannot pass this on to their children. The neuropathy works by affecting the mitochondria or powerhouse of the cells. The retinal cells are full of mitochondria which provide energy to the cells. Since the destruction is centered on these mitochondria, the cell loses its energy maker, and will eventually die. A drug called Idebenone is being tested on patients who have just recently acquired this illness. The clinicians are hoping that the results will prove to be fruitful.