Categories
Ailmemts & Remedies

Scotoma

Definition:A scotoma (Greek: darkness; plural: “scotomas” or “scotomata”) is an area or island of loss or impairment of visual acuity surrounded by a field of normal or relatively well-preserved vision.
Every normal mammalian eye has a scotoma in its field of vision, usually termed its blind spot. This is a location with no photoreceptors, where the retinal ganglion cell axons that comprise the optic nerve exit the retina. This location is called the optic disc. The blindspot does not intrude into consciousness because the corresponding visual field locations of the optic discs in the two eyes differ: The visual signals that are absent in one eye are sent to the cortex by signals from the other eye.

click to see the picture

The presence of the scotoma can be demonstrated subjectively by covering one eye, carefully holding fixation with the open eye, and placing an object (such as your thumb) in the lateral and horizontal visual field, about 15 degrees from fixation (see the blind spot article). The size of the monocular scotoma is surprisingly large – 5×7 deg of visual angle.

It is a common type of vision loss post stroke or traumatic brain injury, a scotoma is an island of visual field loss (blindness) or impaired vision surrounded by relatively normal vision. The eyes of mammals naturally have a small scotoma (blind spot) that we normally don’t detect. However, a wide range of diseases and injuries can cause a pathological scotoma. For example, a scotoma can be a sign of optic nerve damage sustained during a stroke or brain injury. Previously considered untreatable, new research has led to exciting developments in treating scotoma.

Types of Scotoma: After a stroke or brain injury, a scotoma may occur in any shape or size, and it may affect any portion of the visual field. In some cases, a scotoma will include and enlarge the blind spot occurring naturally in a person’s eye. The main types of scotomas include:

* Central scotoma: an area of decreased or lost vision that interferes with central vision (likely to affect daily life)...CLICK & SEE
* Hemianopic scotoma: an area of decreased or lost vision that affects half of the central visual field….CLICK & SEE
* Peripheral scotoma: an area of decreased or lost vision toward the edge of the visual field (less likely to affect daily life)...CLICK & SEE

Symptoms: The main symptom of scotoma is one or more dark, light, or blurred areas in the field of vision. Those affected by visual field loss may also experience a need for greater illumination and contrast when reading, and may have difficulty perceiving certain colors.

click to see

Symptom-producing or pathological scotomata may be due to a wide range of disease processes, affecting either the retina (in particular its most sensitive portion, the macula) or the optic nerve itself. A pathological scotoma may involve any part of the visual field and may be of any shape or size. A scotoma may include and enlarge the normal blind spot. Even a small scotoma that happens to affect central or macular vision will produce a severe visual handicap, whereas a large scotoma in the more peripheral part of a visual field may go unnoticed by the bearer due to the normal reduced visual resolution in the peripheral visual field.

Causes:Common causes of scotomata include demyelinating disease such as multiple sclerosis (retrobulbar neuritis), toxic substances such as methyl alcohol, ethambutol and quinine, nutritional deficiencies, and vascular blockages either in the retina or in the optic nerve. Scintillating scotoma is a common visual aura in migraine.   Less common, but important because sometimes reversible or curable by surgery, are scotomata due to tumors such as those arising from the pituitary gland, which may compress the optic nerve or interfere with its blood supply.

Rarely, scotomata are bilateral. One important variety of bilateral scotoma may occur when a pituitary tumour begins to compress the optic chiasm (as distinct from a single optic nerve) and produces a bi-temporal hemicentral scotomatous hemianopia. This type of visual field defect tends to be very eloquent symptom-wise but often evades early objective diagnosis, as it is more difficult to detect by cursory clinical examination than the classical or text-book bi-temporal peripheral hemianopia and may even elude sophisticated electronic modes of visual field assessment.

In a pregnant woman, scotomata can present as a symptom of severe preeclampsia, a form of pregnancy-induced hypertension.

Click To learn about Detection:->

* Amsler grid…..CLICK & SEE
* Perimetry……..CLICK & SEE
* Visual field test….CLICK & SEE

Treatment: There is no treatment for scotomas.

When they are in the peripheral areas and are not large, they usually do not cause severe problems in general visual functioning. If the scotomas are large or numerous, mobility may be affected.

Central scotomas are another situation entirely. Functional acuity is severely affected and educational adjustments are indicated. Magnification or large print may be indicated. Higher levels of illumination and good contrast in reading materials may also be useful. Color perception may be affected.

Vision loss post stroke or brain injury, which may include scotoma, hemianopia / quadrantanopia, and diffuse field defect / low vision, can drastically impact a person’s quality of life. In the past, these vision defects were considered untreatable. However, cutting-edge research into neuroplasticity, the brain’s ability to grow and heal throughout adulthood, has led to effective methods of vision rehabilitation.

Developed by NovaVision, one such method of vision rehab, called Vision Restoration Therapy, works by stimulating the brain in precise, consistent ways. Studies show that 70 percent of patients who complete Vision Restoration Therapy experience significant improvements in their vision, which improves their quality of life. Today, the therapy is available at premier institutions and medical centers across the United States.

Disclaimer: This information is not meant to be a substitute for professional medical advise or help. It is always best to consult with a Physician about serious health concerns. This information is in no way intended to diagnose or prescribe remedies.This is purely for educational purpose

Resources:
http://www.helpforvisionloss.com/vision-loss/scotoma/#types
http://en.wikipedia.org/wiki/Scotoma
http://www.spedex.com/resource/documents/veb/scotoma.html

[amazon_link asins=’B00AF002YY,B00GWQYLTC’ template=’ProductCarousel’ store=’finmeacur-20′ marketplace=’US’ link_id=’4da4c009-ef55-11e6-b55b-f9978983a1c2′]

Categories
News on Health & Science

Probiotic Hope For Kidney Stones

[amazon_link asins=’B00Q3K6ZFU,B002S1U7RU,B00L3JTHME,B00XRWDW5I,B00JEKYNZA,B01EY4MRIU’ template=’ProductCarousel’ store=’finmeacur-20′ marketplace=’US’ link_id=’7a2b5239-d2c1-11e7-a303-1b4597a754a2′]

Treating patients with bacteria may be an effective way of reducing their risk of repeatedly developing painful kidney stones, a study suggests.

CLICK & SEE

.Kidney stones can cause severe pain

People naturally carrying the bacterium Oxalobacter formigenes were found to be 70% less likely to have problems.

Researchers at Boston University, in the US, are now investigating the possibility of using the bacteria as a “probiotic” treatment.

The study features in the Journal of the American Society of Nephrology.

Kidney stones are small, hard lumps formed of waste products contained in the urine.

They normally range in size from a grain of sand to a pearl. They can be smooth or jagged, and are usually yellow or brown.

Once a kidney stone has formed in a kidney it may travel down through the other parts of the urinary system, where they can slow the flow of urine, cause infection, severe pain and even lead to kidney failure.

About three in 20 men and one in 20 women in the UK will develop a kidney stone at some point in their lifetime.

They are most likely to occur in people aged 20 to 40.

Up to 80% of kidney stones are predominately composed of a compound called calcium oxalate.

O. formigenes breaks down oxalate in the intestinal tract and is present in a large proportion of the normal adult population.

The Boston team compared 247 patients with recurrent calcium oxalate kidney stones with 259 people with no history of the condition.

They found just 17% of the kidney stones group were colonised with O. formigenes, compared with 38% of healthy group.

Researcher Professor David Kaufman: “Our findings are of potential clinical importance.

“The possibility of using the bacterium as a probiotic is currently in the early stages of investigation.”

Promising avenue:

Derek Machin, clinical director of urology at University Hospital, Aintree, said an effective treatment for recurrent kidney stones would be a significant step forward.

He said bigger kidney stones were currently treated by using shock waves to break them up, but this was not always completely effective.

Passing a stone in the urine intact can be extremely painful, and even getting rid of the smaller pieces created by shock treatment could cause significant pain.

“For some people kidney stones can be an on-going lifelong problem,” he said.

“And in some cases a stone can destroy kidney function before it is even identified.”

However, Mr Machin warned that there was much work to be done before clinical trials of a probiotic could be considered.

He said kidney stones had been linked to dehydration and were more common in countries such as Saudi Arabia where the climate is hot and dry.

In instances they may be linked to an unusually high rate of calcium excretion.

However, he said in many cases there was no obvious cause for the condition.

It is a particular problem for airline pilots, who are not allowed to fly if they have a stone.

Click to see also:->

‘Stethoscope’ hears kidney stones
Quick kidney failure test ‘found’
‘Biological’ kidney implant hope
Transplant goal ‘one step closer’

Kidney test may cut dialysis need

Human kidneys grown in mice
Kidney failure
Better kidney care plan unveiled

Sources: BBC NEWS:9Th.March.’08