Optic atrophy

Optic atrophy is the result of the fibres of optic nerve failing to transmit the visual information to the brain due to the damaged optic nerve which may result in problems with vision. Optic atrophy refers to the loss or damage of the fibres of the optic nerve. Optic nerve is responsible for carrying images from the eye to the brain. Optic atrophy presents itself with pale appearance of the optic nerve head at the back of the eye; hence this condition is also referred to as optic nerve head pallor. Although optic atrophy affects one eye, bilateral optic atrophy can also occur when the illness damages the nerves of the both eyes.

What causes optic atrophy ?

Optic atrophy is a serious eye disorder that is caused by a underlying disease or condition. Few of the diseases originating in the eye and the nervous system that lead to optic Atrophy are given below.

• Compression of the optic nerve.
  
• Glaucoma or high pressure within the eye.
  
• Infection
  
• Multiple sclerosis
  
• Inflammation of the optic nerve called optic neuritis.
  
• Interruption in blood circulation to the optic nerve in the form of decreased blood supply (ischemia) or oxygen supply (hypoxia).
  
• Tumors on the visual pathway
  
• Trauma
  
• Optic atrophy can even be inherited from parents.
  
• Nutritional deficiencies (especially B12), certain medications and exposure to certain toxins also lead to optic atrophy.
  

Symptoms of optic atrophy

If you face any of these symptoms seek medical attention immediately as any progression of optic atrophy leads to vision loss. Though the occurrence of these symptoms does not necessarily mean optic atrophy, it is always better to rule out this severe eye condition. Ophthalmologist will examine the eyes with an ophthalmoscope and the doctor may recommend few more tests, if he suspects optic atrophy. Tests such as tonometry, pupil light reflex, color vision and visual acuity are conducted.

• Blurred vision
  
• Poor visual function such as low clarity of vision or visual acuity.
  
• Distorted peripheral vision.
  
• Problems in color vision
  
• Decreased brightness in the affected eye. Diminished reaction of the pupil to the light.
  
• Change in the optic disc

Treatment of optic atrophy

Currently there is no sure shot and effective treatment or therapy available for optic atrophy. However ophthalmologist diagnose the underlying condition or disorder that is causing optic atrophy and treat them. This will avoid the further damage of the optic nerve and preserve the existing vision.

Amaurosis

The term Amaurosis is taken from Greek meaning dark or obscure. It is loss of vision or weakness that occurs without any apparent lesion affecting the eye. Amaurosis is often a short lived episode of blindness in one eye and is referred to as 'fleeting blindness'. An episode of amaurosis if often frightening. Although the visual loss gradually resolves, it is advised to seek medical attention immediately as this may be one of the warning signs of a stroke. Amaurosis is caused due to blood clot or a small piece of cholesterol that breaks off from a large artery and travels upward to the brain or eye. This gets lodged in the main artery supplying blood to the eye. Amaurosis is also caused by blood clots from heart valves or the heart itself due to underlying heart disease.

There are various types of amaurosis. The Leber's congenital amaurosis is inherited. This results in optic atrophy and results in severe vision loss. Amaurosis fugax is a temporary loss of vision in one eye. This is caused by decreased blood flow to the retina. While the majority experiencing amaurosis have a complete symptom abeyance within a few minutes, there is a minority who experience a stroke or a vision loss as a result of amaurosis.

Diabetes, hypertension and smoking tend to aggravate this condition. Sometimes, surgical repair of the mitral valve may result in amaurosis. Deficiency of Vitamin B1 due to Thiamine related cerebrocortical necrosis can also result in amaurosis. Treatment of amaurosis depends mainly upon identifying the source of blood clots and cholesterol that have caused this block in the artery. An ultrasound of the carotid arteries of the neck, a study of the electrical system of the heart and a magnetic resonance angiography scan of the head and neck, an echocardiogram of the heart are often included to reveal the source of the problem and decide on the treatment options.

Hallervorden spatz disease

Hallervorden Spatz disease or HSD is a rare neurological movement disorder that is passed down through families. It is characterized by progressive degeneration of the nervous system. According to the National Institute of Health, Hallervorden Spatz disease or its subtype affects less than 200,000 people in the US population.

Hallervorden Spatz disease was first described in 1922 as a form of brain degeneration characterized by iron deposition in the brain. The most recently used term for HSD is 'panthothenate kinase – associated neuro degeneration' as HSD specifically causes neuro degeneration and excessive iron accumulation. Onset of the disease is commonly in late childhood or early adolescence but there are cases with adult onset as well. The disease can be familial or sporadic. When familial it is inherited recessively.

Symptoms of Hallervorden spatz disease

• Motor disorder of extra pyramidal type and gait difficulty.
  
• Rigidity of extremities, slowness of movement.
  
• Predominant tremor – continuous shaking especially in the hands.
  
• Dystonia or involuntary muscle contractions – tight, weak and spastic muscles.
  
• Movement defects with uncontrollable twisting and squirming.
  
• Spasticity and dysarthria (speech disturbance caused by lack of control over muscles involved in speech) , brisk reflexes and extensor plantar responses.
  
• Significant disturbance in speech at an early age.
  
• Dementia is present in most individuals with HSD.
  
• Visual impairment from optic atrophy or retinal degeneration.
  
• Seizures
  

Hallervorden Spatz disease may possibly cause several other diseases including Cerebellar syndrome, Choreoathetosis, Chronic brain failure, Fits, Parkinsonism, Retinitis pigmentosa and Spastic ataxia.

Diagnosis of Hallervorden spatz disease

A neurological examination will reveal abnormal postures and movements, muscle rigidity, tremors and weakness. Genetic tests help to detect defective gene that causes the disease. However, this test is not widely available. MRI and similar other tests help to rule out the movement disorders and diseases.

Hallervorden Spatz disease gets worse and nerves are damaged over time. This leads to lack of movement and often death by early adulthood. Hence, treatment to control the symptoms becomes imperative. But there are no specific lines of treatment for HSD, consuming certain vitamins like panthothenate, Coenzyme Q10 and antioxidants can help the patient to some extent as they help ease the symptom severity. Sometimes medications used to treat symptoms for HSD can cause additional complications. These include blood clots, respiratory infections and skin breakdown.