What happens if there is a lesion at the optic chiasm?
A lesion involving complete optic chiasm, which disrupts the axons from the nasal field of both eyes, causes loss of vision of the right half of the right visual field and the left half of the left visual field. This visual field defect is called as bitemporal hemianopia.
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 happens if there is a lesion in the left optic tract?
A lesion in one optic tract, interrupting all fibers carrying information from the contralateral visual fields, may cause homonymous hemianopia. When an injury to the left optic tract occurs, the patient will have visual difficulties (visual field cuts) in the right eye’s inner field, but in the left eye’s outer field.
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 is the most common cause of visual field defects caused by post Chiasmal lesions?
The usual suspects are pituitary adenomas, craniopharyngiomas, and meningiomas. Pituitary tumors are the most common cause of chiasmal syndromes. Visual field defects may be one of the first signs of non-functional pituitary tumor. These are much less frequent than functional adenomas.
What effects would a lesion have on the right optic nerve?
A lesion of the right optic nerve causes a total loss of vision in the right eye; it also produces a right afferent pupil deficit.
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 causes optic tract lesions?
Incomplete bilateral optic tract lesions may produce partial bilateral visual deficit with variable pupillary responses. The most common histopathologic finding in optic tract disease is demyelination. It may be caused by canine distemper, which has a predilection for the optic tracts.
What is the primary problem in visual functional disease?
Functional Visual Loss (FVL) is a decrease in visual acuity and/or visual field not caused by any organic lesion. It is therefore also called “nonorganic visual loss” (NOVL). This entity is considered within the spectrum of “conversion disorder”, malingering, somatic symptom disorder, and “factitious disorder”.
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.
Can optic nerve damage be treated?
Unfortunately, once damaged, the optic nerve cannot be repaired since the damage is irreversible. The optic nerve is composed of nerve fibers that do not possess the ability to regenerate on their own. The nerve fibers, if damaged, cannot heal on their own.
What is a chiasmal lesion of the chiasm?
However, the many possible locations of lesions in the region of the chiasm produce widely varying visual field defects depending on the specific eti-ology. Bilateral temporal visual field defects are due to chiasmal lesions. A chiasmal lesion should always be considered in the presence of any uncertain visual field defect.
What is chiasmal ophthalmic chiasm?
Optic Chiasm. A chiasmal process should be considered in patients with temporal field defects that respect the vertical meridian in either or both eyes or in patients with visual loss of any type accompanied by an endocrinopathy.
How is a chiasmal lesion diagnosed in diabetic retinopathy (DRS)?
A chiasmal lesion should always be considered in the presence of any uncertain visual field defect. Further diagnostic studies may be performed after visual acuity testing, pupil-lary light reaction testing, perimetry, and ophthalmoscopy of the fundus and optic disk.
What does an anterior angle chiasm lesion mean?
The anterior angle. Lesions that involve the anterior angle of the chiasm, the point at which the optic nerve passes into and forms the chiasm, may show a junctional scotoma (Traquair, 1949) since there is at this point separation of the crossing and uncrossed fibers.