For appointments call 9910009144 & 9540009144       .
EyeCareDelhi
Search the web:
 Dr. Sanjay Dhawan
Optic Nerve Disorders
What is it?
What Causes it?
Who are at risk?
What are the symptoms & signs?
How is it diagnosed?
What is the treatment?
What are the surgical options?
 
What is it?
 

Optic Nerve Disorders are a set of diseases that disrupt the normal function of the eye. The optic nerve located at the back of the eye responsible for carrying messages to/from the brain where visual information is decoded. When this nerve is damaged due to disease, age or sports related trauma it can interfere with the nerve’s ability to function properly. Those with multiple sclerosis and pseudotumor cerebri often suffer optic nerve damage as a result of their illness.

What Causes it?
 

Damage to the optic nerve typically causes permanent and potentially severe loss of vision, as well as an abnormal pupillary reflex, which is diagnostically important. The type of visual field loss will depend on which portions of the optic nerve were damaged.

In general:
• Damage to the optic nerve anterior to the optic chiasm causes loss of vision in the eye on the same side as the damage.
• Damage in the optic chiasm causes loss of vision laterally in both visual fields (bitemporal hemianopsia). It may occur in large pituitary adenoma.
• Damage to the optic tract posterior to the chiasm causes loss of vision in the visual field on the side opposite to the damage.

Injury to the optic nerve can be the result of congenital or inheritable problems like Leber's Hereditary Optic Neuropathy, glaucoma, trauma, toxicity, inflammation, ischemia, infection (very rarely), or compression from tumors or aneurysms. By far, the three most common injuries to the optic nerve are from glaucoma, optic neuritis (especially in those younger than 50 years of age), and anterior ischemic optic neuropathy (usually in those older than 50).

Glaucoma is a group of diseases involving loss of retinal ganglion cells causing optic neuropathy in a pattern of peripheral vision loss, initially sparing central vision. Optic neuritis is inflammation of the optic nerve. It is associated with a number of diseases, the most notable one being multiple sclerosis.

Anterior Ischemic Optic Neuropathy is a particular type of infarct that affects patients with an anatomical predisposition and cardiovascular risk factors.

Optic nerve hypoplasia is the underdevelopment of the optic nerve causing little to no vision in the affected eye.

A variety of diseases, disorders and conditions originating most often in the eye and the nervous system can lead to optic nerve disorder. Optic nerve damage can result from:

Compression of the optic nerve
Glaucoma, or high pressure within the eye
Infection
Inflammation
Interruption in blood circulation to the optic nerve
Malignancy (cancer)
Trauma

Who are at risk?
 

Patients having glaucoma,infection.inflammation,interruption in blood circulation of the optic nerve ,cancer and any trauma of eye are more prone to optic nerve disorders.Optic nerve damage is any kind of injury or damage to the optic nerve, including trauma, inflammation, disease or deterioration. Optic nerve damage is also called optic nerve atrophy or optic neuropathy. The optic nerve is the nerve that connects and transmits information between the eye and the brain. Optic nerve damage can lead to vision distortion, vision loss, and blindness.Within the eye, there are many elements that work together to create vision. Light flows through the cornea and the pupil into the lens before it is projected onto the retina in the back of the eye. The retina transforms light into electrical impulses that are transmitted by the optic nerve to the brain. The eyes are protected by the bones of the orbit and move through the actions of the eye muscles, which are controlled by nerves.

What are the symptoms & signs?
 

Optic nerve damage can cause symptoms that affect the eyes and your vision, which may occur in one or both eyes including:

Bulging of the eyes
Complete or partial loss of vision
Diminished ability to see fine details
Diminished color vision or colors seem faded
Dimming or blurring of vision
Double vision
Eye redness
Impaired reaction of the pupil to light or dilated pupil
Involuntary movement of the eyes
Seeing blind spots in your peripheral vision
Seeing rainbows or halos
Severe eye or brow pain or pain when moving the eye.

How is it diagnosed?
 

Ophthalmologists and optometrists can detect and diagnose some optic nerve diseases but, those sub-specialists that are neuro-ophthalmologists, are often best suited to diagnose and treat diseases of the optic nerve.

What is the treatment?
 

Treatment depends upon the cause of optic nerve disorders. Vision is required for communication, access to information, and mobility. The maximum distance at which faces can be seen, and facial expressions seen and learned from, needs to be determined and conveyed to parents and carers. The language framework required to compensate for reduced vision should be established. The size and contrast, and the proximity of toys and printed information required for maximum speed of access to the information need to be determined. The provision of low-vision aids at an early stage warrants consideration. The visual limitations to all aspects of mobility need to be understood and compensated for

What are the surgical options?
 

Surgical options also depends upon the cause of disorder.

What are the outcomes?
 

The outcomes are variable from person to person, the majority of cases, disorders of optic nerve structure are sporadic and the aetiology is unknown. A positive approach aimed at habilitation and optimising visual function from an early stage during development reaps dividends. An approach that says 'there is nothing more I can do' should be a thing of the past . Early intervention can contribute significantly to a positive developmental outcome. This needs to be put in place at an early stage by notifying and informing the appropriate authorities.

What are the complications?
 

A small proportion of cases are associated with cysts arising from the optic nerve sheath, which communicate with the subarachnoid space. Rarely such cysts can enlarge and lead to compressive optic neuropathy.

Peripapillary choroidal neovascularisation has been described in association with optic nerve coloboma. Retinal detachment is also a recognised complication, and remarkably, spontaneous re-attachment may occur. The source of the subretinal fluid is not known but could derive from fluid entering the retrobulbar space from surrounding orbital tissue, or from the choriocapillaris, or from CSF. In contrast to retinochoroidal colobomas, rhegmatogenous detachment is probably not a recognised association.

Contrary to what is commonly taught, basal encephalocele is a rare association with optic nerve coloboma (in contrast to the more common association with morning glory syndrome.

What is the time course?
 

Early intervention can contribute significantly to a positive developmental outcome. This needs to be put in place at an early stage by notifying and informing the appropriate authorities.

What is the expense?
 

The expense depends upon the grades of treatment.

 
Author: Dr. Sanjay Dhawan
Last Updated on: 1 March, 2014
   

Complete Eye Care
Complete Eye Examination
Computer Vision Syndrome
Glaucoma
Macular Degeneration (ARMD)
Retina Detachment