Optic atrophy (optic neuropathy) is a term used to refer to the end stage of a number of conditions that can cause optic nerve damage. The optic nerve is composed of a bundle of nerve fibers, each of which transports visual information from the retina to the visual processing centers of the brain. Significant damage or degeneration of the optic nerve due to any cause can result in vision loss.
Those suffering from poor blood supply to the optic nerve (ischemic optic neuropathy) are the most at risk for optic atrophy, with the elderly being the most common demographic affected. However, optic atrophy may also be caused by shock, radiation, toxic substances, or trauma. Disease of the brain or central nervous system, stroke, brain tumor, as well as eye diseases such as glaucoma may also lead to the condition.
In the United States, the prevalence of blindness attributable to optic atrophy is about 0.8 percent. However, other sources have found this number to be as high as 0.12 percent. Optic atrophy is not a disease, but a sign of many disease processes.
The term “optic atrophy” implies the wasting away of optic nerve cells due to underuse or neglect, which is not a completely accurate description of the condition, as damage to the optic nerve is a causative factor. Any disease that can compromise ganglion cell function (a type of neuron found near the inner surface of the retina) can lead to the development of optic atrophy over time.
The following are some of the most commonly recognized optic atrophy causes:
A progressive condition that causes pressure build-up within the eyes, which can lead to optic nerve damage. Intraocular pressure – the pressure within the eye – damages the optic nerve, which is responsible for sending the images you see to the brain to be interpreted.
When this nerve becomes damaged, it can lead to significant sight impairment or even blindness in just a few years. One of the most troubling aspects of glaucoma is that in its initial phases, it may not present with any symptoms, and it is not until you start to notice problems with your vision that glaucoma cases are diagnosed.
It is recommended that those over 40 years old who have a family history of glaucoma have a complete eye exam from an eye doctor every one to two years. This is especially important if you suffer from a health condition such as diabetes or high blood pressure, as these may also affect eye health.
A form of optic neuritis or inflammation of the optic nerve. Inflammation is a normal immune process, but it can still attack and damage healthy tissue in autoimmune conditions or other pathologies. Because the optic nerve is an important player in visual signaling to the brain, inflammation of it is often impaired. Inflammation of the optic nerve can be seen in conditions such as multiple sclerosis, diabetes mellitus, low phosphorus levels, or hyperkalemia.
Occurs due to indirect injury to the optic nerve that is thought to be the result of transmitted shock from impact created to the intracanalicular portion of the optic nerve. This may occur from penetrating injury or from bony fragments in the optic canal or orbit that pierce the optic nerve. Significant trauma leading to orbital hemorrhage and optic nerve sheath hematoma can lead to optic neuropathy as well.
A condition characterized by blockage of a vein of the eye that normally funnels deoxygenated blood away from the eye. As a result, blood begins to back up within the eye, spilling out into the retina. This leads to swelling of the macula (a small but important area in the center of the retina needed to see details of objects clearly) affecting central vision. If this blood supply abnormality is not corrected, nerve cells within the eye can die, leading to a loss of vision.
Optic nerve atrophy symptoms will ultimately depend on the underlying condition but typically include the following:
The diagnosis of virtually any eye condition will be done by an ophthalmologist, as they are skilled at identifying and assessing various forms of vision loss and eye pathology. If your ophthalmologist suspects you may be suffering from optic atrophy, the first thing they will do is get a direct close up look at the eye with a tool called an ophthalmoscope. This tool will allow your doctor to look at the optic disc (the point where the optic nerve enters). Depending on the color of this disc, change in blood flow to the eye can be suspected. A pale optic disc would indicate decreased blood flow, for example.
Other tests may also be done depending on the suspected cause of optic atrophy. If your doctor suspects that a tumor is the most likely cause of your changes in vision, imaging studies will be ordered, such as a magnetic resonance imaging (MRI) test. Ancillary tests to measure your vision and peripheral and color vision will also be done.
While it may not always be possible to prevent optic nerve atrophy, taking the following steps is considered the most effective method of prevention:
The prognosis of optic atrophy will depend on the severity of the underlying condition causing the problem. Some causes, such as inflammation of the optic nerve (optic neuritis), may resolve any vision problems once the inflammation has cleared up, but other causes may not see any improvement in vision at all. The most proactive thing to do is to have any potential eye condition diagnosed early by maintaining routinely scheduled doctors visits.