Vision is a complex system that requires the eyes, brain, and the connection between the two to work correctly. Neuro-ophthalmological causes occur when vision loss is due to more complex issues than just eye disorders. There are various conditions that cause vision loss because of changes in the visual system.
Stroke can cause damage to the muscles or nerves responsible for eye movement and vision. Since most strokes only affect one side of the brain, the resulting problems typically affect vision on the contralateral side. Problems with the muscles of the eye can cause vision loss because the eye can no longer move in various directions to follow objects or there may be drooping of the eyelid obstructing vision. When the nerves responsible for vision are damaged, they can cause unique vision issues. For example, vision loss may only occur in half or a quarter of the visual field in one or both eyes.
Multiple sclerosis (MS) is an autoimmune disease that affects nerve conduction throughout the body. When MS affects vision, the most common cause is optic neuritis. This means the nerve going to the eye is inflamed. When this occurs, the most common symptom is pain in or behind the eye. Vision is typically blurry and there may be changes in vision, such as loss of color vision. Optic neuritis is episodic and often occurs during relapses of MS. However, once the episode has passed, it may leave permanent vision changes. Nystagmus is another way MS can affect the eyes. The condition causes involuntary movements of the eyes. The eyes will jump around, typically from side-to-side. This can make it seem like the visual field is moving. Nystagmus may occur temporarily, often with MS relapses, or it may become a chronic problem.
Both benign and malignant tumors may cause vision loss if they affect the nerves connecting the eyes and brain. The most common reason tumors cause vision loss is because they may exist in a location that causes pressure on the optic nerve. Since the optic nerve is quite sensitive, if the tumor is not caught and removed in the earlier stages, it will likely cause permanent damage. Cancers of the eye are uncommon, but melanoma is one type of cancer that may directly affect vision. Melanoma affects the pigment-producing cells in the body (melanocytes). Although it most commonly affects the melanocytes in the skin, the eye also has melanocytes.
Problems with vision are common, but the underlying issue may be more complex. Vision loss may occur because of brain damage or problems with the connection between the eyes and the brain. For more information on vision loss, contact a professional near you.