User:Parshwaparikh

Summary: Glaucoma usually develops slowly and sometimes without any notable sight loss over many years. Symptoms of optic atrophy include changes in the optic disc and decrease in visual function.

1.An eye with AAC, with clinical signs of a mid-dilated pupil, hazy cornea and injected11 blood vessels (courtesy of medical illustrations, Moorﬁelds Eye Hospital). communication, D. Siriwardena). In the Rotterdam eye study, 2% of an unselected population aged 55 years and over had a narrow anterior chamber angle at risk of closure on examination of the limbal chamber depth. This was twice as high in women as men. In the Egna-Neumarkt study in Northern Italy, angle-closure glaucoma was found in 0.6% of the population, accounting for a quarter of all the glaucoma cases. Drugs and poisons, both therapeutic and recreational, as well as environmental factors have been linked to the development of angle closure in susceptible patients. These often present with symptoms, but may have a ‘chronic’ insidious course leading to PACG. Best current evidence does not support the use of a classification system focused on symptomatology to describe PACG. This review is focused on the drug and environmental mechanisms that may trigger angle closure and lead to glaucomatous neuropathy if left untreated. It will allow the reader to identify patients at risk and the rationale behind the treatment of these cases. The Optic Nerve

2.The optic nerve (also known as cranial nerve II) is a continuation of the axons of the ganglion cells in the retina. There are approximately 1.1 million nerve cells in each optic nerve. The optic nerve, which acts like a cable connecting the eye with the brain, actually is more like brain tissue than it is nerve tissue.

visual pathway

As the optic nerve leaves the back of the eye, it travels to the optic chiasm, located just below and in front of the pituitary gland (which is why a tumor on the pituitary gland, pressing on the optic chiasm, can cause vision problems). In the optic chiasm, the optic nerve fibers emanating from the nasal half of each retina cross over to the other side; but the nerve fibers originating in the temporal retina do not cross over.

From there, the nerve fibers become the optic tract, passing through the thalamus and turning into the optic radiation until they reach the visual cortex in the occipital lobe at the back of the brain. This is where the visual center of the brain is located.

The visual cortex ultimately interprets the electrical signals produced by light stimulation of the retina, via the optic nerve, as visual images. A representation of parasympathetic pathways in the pupillary light reflex can be seen here: parasympathetic response. blind spot

The beginning of the optic nerve in the retina is called the optic nerve head or optic disc. Since there are no photoreceptors (cones and rods) in the optic nerve head, this area of the retina cannot respond to light stimulation. As a result, it is known as the “blind spot,” and everybody has one in each eye.

The reason we normally do not notice our blind spots is because, when both eyes are open, the blind spot of one eye corresponds to retina that is seeing properly in the other eye....

Optic atrophy:

“Optic atrophy” of the optic disc (visible to an eye doctor looking inside the eye) is the result of degeneration of the nerve fibers of the optic nerve and optic tract. It can be congenital (usually hereditary) or acquired.

If acquired, it can be due to vascular disturbances (occlusions of the central retinal vein or artery or arteriosclerotic changes within the optic nerve itself), may be secondary to degenerative retinal disease (e.g., optic neuritis or papilledema), may be a result of pressure against the optic nerve, or may be related to metabolic diseases (e.g., diabetes), trauma, glaucoma, or toxicity (to alcohol, tobacco, or other poisons).

Loss of vision is the only symptom. A pale optic disc and loss of pupillary reaction are usually proportional to the visual loss. Degeneration and atrophy of optic nerve fibers is irreversible, although in some cases, intravenous steroid injections have been seen to slow down the process... is the final common morphologic endpoint of any disease process that causes axon degeneration in the retinogeniculate pathway. Clinically, optic atrophy manifests as changes in the color and the structure of the optic disc associated with variable degrees of visual dysfunction. Optic atrophy is actually a misnomer; in the strict histologic definition, atrophy refers to involution of a structure resulting from prolonged disuse. Glaucoma affects over three million Americans. When the drainage canals in the eye become clogged, the pressure inside the eye, called intraocular pressure (IOP), rises as fluid can't drain out of the eye.

Most people have no symptoms and no warning signs. If glaucoma is not diagnosed and treated, it can cause a gradual loss of vision. Glaucoma usually develops slowly and sometimes without any notable sight loss over many years.

Optic atrophy is damage to the optic nerve that causes degeneration or destruction of the optic nerve. Optic atrophy, also known as optic nerve head pallor, due to the pale appearance of the optic nerve head seen in the back of the eye.

Symptoms of optic atrophy include changes in the optic disc and decrease in visual function. Change in visual function can include decrease in sharpness and clarity of vision (visual acuity) or decrease in side (peripheral) vision. Sometimes color vision and contrast sensitivity are also affected.

Some possible causes of optic atrophy are optic neuritis, Leber's hereditary optic atrophy, toxic or nutritional optic neuropathy, glaucoma, vascular disorders, trauma, and other systemic disorders.