What happens when optic chiasm is damaged?

Damage to the retina or one of the optic nerves before it reaches the chiasm results in a loss of vision that is limited to the eye of origin. In contrast, damage in the region of the optic chiasm—or more centrally—results in specific types of deficits that involve the visual fields of both eyes (Figure 12.8).

What symptoms would Chiasmal compression cause?

The symptoms of compressive lesions of the optic chiasm vary among patients and can be very diverse. Symptoms include not only decreased visual acuity and visual field defects, but also endocrine symptoms, headache, and photophobia1,2.

What causes lesions on the optic nerve?

Bacterial infections, including Lyme disease, cat-scratch fever and syphilis, or viruses, such as measles, mumps and herpes, can cause optic neuritis. Other diseases. Diseases such as sarcoidosis, Behcet’s disease and lupus can cause recurrent optic neuritis.

What happens if the lateral geniculate nucleus is damaged?

Damage at site #4 and #5: damage to the optic tract (#4) or the fiber tract from the lateral geniculate to the cortex (#5) can cause identical visual loss. In this case, loss of vision of the right side. Partial damage to these fiber tracts can cause other predictable visual problems.

What diseases can affect the optic chiasm?

Diseases of the Optic Chiasm

  • Inflammatory disorders such as multiple sclerosis.
  • Infections such as tuberculosis.
  • Benign (noncancerous) tumors and cysts.
  • Cancerous tumors.
  • Vascular (blood vessel) disorders.

Which part of the brain is the optic chiasm?

The optic chiasm, or optic chiasma, is the part of the brain where the optic nerves cross and is therefore of primary importance to the visual pathway. It is located at the base of the brain inferior to the hypothalamus, and approximately 10 mm superior to the pituitary gland within the suprasellar cistern.

What is Chiasmal compression?

Abstract. Compression of the optic chiasm causes an optic neuropathy that may be associated with reversible visual loss often immediately following surgical decompression.

What is anterior Chiasmal syndrome?

Anterior Chiasmal Syndrome is the condition in which the tumor compresses one optic nerve more than the other and affects nasal as well as macular fibers on that side. This leads to a bitemporal hemianopia with a central scotoma in the more affected eye.

What happens when there is a lesion in optic nerve?

Lesions involving the whole optic nerve cause complete blindness on the affected side, that means damage at the right optic nerve causes complete loss of vision in the right eye. Optic neuritis involving external fibers of the optic nerve causes tunnel vision.

Can vision be restored after optic nerve damage?

There are no effective treatments to regenerate nerve cells or to restore connections between the eye and brain once the optic nerve is lost. This is a major barrier in the field and one that must be overcome, given the substantial number of patients suffering from optic neuropathy-associated blindness.

What is the role of the LGN?

The lateral geniculate nucleus (LGN) belongs to the category of sensory projection nuclei of the thalamus and plays an essential role in normal visual processing.

What is the lateral geniculate nucleus responsible for?

Visual System in the Brain The lateral geniculate nucleus is a multilayered structure that receives input from both eyes to build a representation of the contralateral visual hemifield. The basic pattern of the LGN in primates consists of four layers, two each for each eye.

What is Chiasmal optic neuritis?

Disease. Chiasmitis, or chiasmal optic neuritis, is characterized by acute vision loss with a visual field defect and/or radiographic findings consistent with a lesion of the optic chiasm. Chiasmitis can be caused by inflammatory, infectious, toxic, or autoimmune processes.

Can brain lesions cause eye problems?

Can Brain Tumors Affect Your Vision? Yes, they can. Although eye problems typically stem from conditions unrelated to brain tumors—such as astigmatism, cataracts, detached retina and age-related degeneration—they can sometimes be caused by tumors within the brain.

What does optic chiasm mean?

Listen to pronunciation. (OP-tik ky-A-zum) The place in the brain where some of the optic nerve fibers coming from one eye cross optic nerve fibers from the other eye. Also called optic chiasma.

Why would a pituitary tumor affect vision?

Sometimes a pituitary tumor affects the optic nerve on just one side. In other cases, it affects a structure known as the “optic chiasm,” where the optic nerves from each eye merge together. When a pituitary tumor pushes the optic chiasm, it causes visual loss in both eyes.

What are the causes of lesion in optic chiasm?

Other less common causes of chiasmal syndrome are metabolic, toxic, traumatic or infectious in nature. Compression of the optic chiasm is associated with pituitary adenoma, Craniopharyngioma, Meningioma etc.

Can optic nerve damage be repaired?

In the case of the optic nerve, it is a person’s vision that is lost or impaired. The optic nerve is part of the central nervous system and cannot regenerate or repair itself because of natural inhibitors in the body that block its re-growth.

What is the treatment for optic nerve damage?

Optic neuritis usually improves on its own. In some cases, steroid medications are used to reduce inflammation in the optic nerve. Possible side effects from steroid treatment include weight gain, mood changes, facial flushing, stomach upset and insomnia. Steroid treatment is usually given by vein (intravenously).

What vitamin is good for the optic nerve?

Vitamins B12, B6 and B1, called neurotrophic vitamins, are essential to maintain the health of the nervous system, including the optic nerve.