Tag Archives: Vision loss

Ocular Histoplasmosis

Definition:
Ocular histoplasmosis is  an eye disease that is a leading cause of vision loss, due to the spread of spores of the fungus Histoplasma capsulatum (histo) from the lungs to the eye where they lodge in the choroid (a layer of blood vessels that provides blood and nutrients to the retina).

click to see the pictures

There the spores cause fragile, abnormal blood vessels to grow underneath the retina. These abnormal blood vessels form a lesion known as choroidal neovascularization (CNV). If left untreated, the CNV can turn into scar tissue and replace the normal retinal tissue in the macula (the central part of the retina that provides sharp central vision. If these abnormal blood vessels grow toward the center of the macula, they may affect a tiny depression called the fovea (the region of the retina with the highest concentration of special retinal nerve cells, called cones, that produce sharp, daytime vision). Damage to the fovea and the cones can severely impair, and even destroy, straight-ahead vision. Since the syndrome rarely affects side, or peripheral vision, the disease does not cause total blindness.

It’s a common problem in the USA, particularly in a region now known as the ‘Histo belt’, which includes Arkansas, Kentucky, Missouri, Tennessee and West Virginia, where as many as 90 per cent of the population have had the infection.

Symptoms:
Many patients with histo spots in their eyes have no symptoms. Others may experience the following:

 

*Distorted vision…....CLICK & SEE
*Blind spots
*Scars in the retina, ranging in severity

Causes:
Histoplasmosis is caused by a fungus commonly found in the dust and soil of the Mississippi-Ohio River Valley region.  Approximately 62% of the adult population living in this region are carriers. It affects men and women equally.

Histoplasmosis is contracted by inhaling dust that carries the fungal spores. Its effect on the body can vary widely in severity from one person to another.  Many carriers have no symptoms at all, but those with mild exposure may experience flu-like symptoms and mild respiratory infections. Histoplasmosis is more likely to become a serious problem in people who already have a weakened immune system.

The fungus may affect the eye by causing small areas of inflammation and scarring of the retina. These are called “histo spots” and may be found in both eyes. Their affect on vision depends on the location of the scars.  Scarring in the peripheral area of the retina may have little or no impact on vision, while a central scar affecting the macula may cause a prominent blind spot.

Most people with histo spots in the retina are totally unaware of their presence unless the central vision is affected. Studies indicate that only about 5% of those with histo spots are at risk of losing vision. Scientists have been unable find a link between the patients with minor histo spots and those who develop a severe loss of their central vision.

The syndrome is thought to be linked to hypersensitivity to Histoplasma capsulatum, rather than a direct exposure of the eyes to the micro-organism, but some experts have found DNA or genetic material from the fungus in a layer of the eyeball known as the choroid, and suspect fungal spores may lodge here and cause problems.

Risk Factors:
Some people go on to develop symptoms – usually of lung disease, although the fungus may spread to other organs – known as disseminated histoplasmosis and this can be fatal.

Very rarely the organism can spread to the eye to cause acute ocular histoplasmosis, which needs urgent treatment with antifungal medicine.

Ocular histoplasmosis can cause blindness, although it mostly affects central vision and rarely involves peripheral vision so total blindness is rare. Anyone who has lived in an area where they may have been exposed to histoplasmosis and develops eye problems must be checked for the condition.The loss of vision in POHS is caused by choroidal neovascularization.

Diagnosis:
Ocular histoplasmosis is detected with a dilated examination of the retina using ophthalmoscopy. It is usually diagnosed based on its distinctive appearance and characteristics. Fluorescein angiography is required for diagnosis and follow-up of patients with POHS.

Treatment:
Treatment requires careful consideration of FA findings and few cases may respond to corticosteroids and laser photocoagulation. A vitreo-retinal specialist should be consulted for proper management of the case.

Presumed ocular histoplasmosis syndrome and age-related macular degeneration (AMD) have been successfully treated by the drug Bevacizumab (trade name Avastin, Genentech/Roche). Ophthalmologists are using Avastin “off-label” to treat AMD and similar conditions since research indicates that vascular endothelial growth factor (VEGF) is one of the causes for the growth of the abnormal vessels that cause these conditions. Some patients treated with Avastin had less fluid and more normal-appearing maculas, and their vision improved. Avastin injections into the affected eye have been used by retina specialists since early 2005. Thus there is no long term 10 to 15 year follow up data for possible late complications. Early treatment is critical to maintaining vision.

Other treatments include Ranibizumab (trade name Lucentis) which is approved by the FDA for intraocular use. Lucentis uses a smaller molecule compared to Avastin and according to GenenTech, the smaller molecule helps lower the systemic toxicity of the drug, thereby lowering the overall risks compared to Avastin. However, Lucentis costs approximately $1,600 per injection compared to less than $100 per injection for Avastin. Research has shown  that Avastin and Lucentis to be equally effective in the treatment of POHS and AMD.

To get the best effect, the whole area affected by ocular histoplasmosis has to be treated.

Once a person has ocular histoplasmosis, they have it for life.

Regular eye exams and routine use of an Amsler Grid to monitor central vision is recommended for anyone with histo spots.

Click to learn more

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://en.wikipedia.org/wiki/Presumed_ocular_histoplasmosis_syndrome
http://www.medterms.com/script/main/art.asp?articlekey=24114
http://www.stlukeseye.com/Conditions/histoplasmosis.html
http://www.bbc.co.uk/health/physical_health/conditions/ocularhistoplasmosis.shtml

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Eyes are Unique Window to Predict Diseases

Looking people straight in the eye may or may not reveal their honesty — but the eyes *can* tell you about cholesterol, liver disease, or diabetes, if you know what to look for.

Click to see the picture

Your eyes are a unique window into health. Yahoo Health has assembled a list of 14 things your eyes can tell you about your entire body.
Some of them are mentioned below:-

*Disappearing eyebrows : When the outer third of your eyebrow starts to disappear on its own, this is a common sign of thyroid disease.

*A stye that won’t go away : If it doesn’t clear up in three months, or keeps recurring in the same location, it could be a rare cancer called sebaceous gland carcinoma.

*Burning eyes, blurry vision while using a computer : This is the result of “computer vision syndrome” (CVS). The eyestrain is partly caused by the lack of contrast on a computer screen, and the extra work involved in focusing on pixels.

*A small blind spot in your vision, with shimmering lights or a wavy line : A migraine aura produces this disturbed vision. It may or may not be accompanied by a headache.

*Whites of the eye turned yellowish : This is known as jaundice. It appears in either newborns with immature liver function, or adults with problems of the liver, gallbladder, or bile ducts.

*Eyes that seem to bulge : The most common cause of protruding eyes is hyperthyroidism, which is overactivity of the thyroid gland.

*Sudden double vision, dim vision, or loss of vision : These are the visual warning signs of stroke.

*Blurred vision in a diabetic : Diabetics are at increased risk for several eye problems, but the most common is diabetic retinopathy, in which diabetes affects the circulatory system of the eye. It’s the leading cause of blindness in American adults.

For the rest of the list, click on the link below.

Sources: Yahoo Health February 3, 2011

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Macular Degeneration (AMD OR ARMD)

Definition:
Macular degeneration is a medical condition usually of older adults which results in a loss of vision in the center of the visual field (the macula) because of damage to the retina. It occurs in “dry” and “wet” forms. It is a major cause of blindness in the elderly (>50 years). Macular degeneration can make it difficult or impossible to read or recognize faces, although enough peripheral vision remains to allow other activities of daily life.

CLICK TO SEE THE PICTURES.>...(01)...…….(1).…………..(2).……..(3)………..(4)

Human eye cross section view

Macular degeneration doesn’t cause total blindness, but it worsens your quality of life by blurring or causing a blind spot in your central vision. Clear central vision is necessary for reading, driving, recognizing faces and doing detail work.

The deterioration occurs in the macula (MAK-u-luh), which is in the center of the retina — the layer of tissue on the inside back wall of your eyeball.

The inner layer of the eye is the retina, which contains nerves that communicate sight, and behind the retina is the choroid, which contains the blood supply to the retina. In the dry (nonexudative) form, cellular debris called drusen accumulate between the retina and the choroid, and the retina can become detached. In the wet (exudative) form, which is more severe, blood vessels grow up from the choroid behind the retina, and the retina can also become detached. It can be treated with laser coagulation, and with medication that stops and sometimes reverses the growth of blood vessels.

Although some macular dystrophies affecting younger individuals are sometimes referred to as macular degeneration, the term generally refers to age-related macular degeneration (AMD or ARMD).

Signs:
Drusen
Pigmentary alterations
Exudative changes: hemorrhages in the eye, hard exudates, subretinal/sub-RPE/intraretinal fluid
Atrophy: incipient and geographic
Visual acuity drastically decreasing (two levels or more) ex: 20/20 to 20/80.

Symptoms:
Dry macular degeneration usually develops gradually and painlessly. You may notice these vision changes:

* The need for increasingly bright light when reading or doing close work
* Increasing difficulty adapting to low light levels, such as when entering a dimly lit restaurant
* Increasing blurriness of printed words
* A decrease in the intensity or brightness of colors
* Difficulty recognizing faces
* Gradual increase in the haziness of your overall vision
* Blurred or blind spot in the center of your visual field combined with a profound drop in the sharpness (acuity) of your central vision
CLICK FOR PICTURE

Normal Vision.……………………………...Vision with AMD

Your vision may falter in one eye while the other eye remains fine for years. You may not notice any or much change because your good eye compensates for the weak one. Your vision and lifestyle begin to be dramatically affected when this condition develops in both eyes.

Hallucinations

Additionally, some people with macular degeneration may experience visual hallucinations as their vision loss becomes more severe. These hallucinations may include unusual patterns, geometric figures, animals or even faces. You might be afraid to discuss these symptoms with your doctors or friends and family for fear you’ll be considered crazy. However, such hallucinations aren’t a sign of mental illness. In fact, they’re so common that there’s a name for this phenomenon — Charles Bonnet syndrome.

The Amsler Grid Test is one of the simplest and most effective methods for patients to monitor the health of the macula. The Amsler Grid is essentially a pattern of intersecting lines (identical to graph paper) with a black dot in the middle. The central black dot is used for fixation (a place for the eye to stare at). With normal vision, all lines surrounding the black dot will look straight and evenly spaced with no missing or odd looking areas when fixating on the grid’s central black dot. When there is disease affecting the macula, as in macular degeneration, the lines can look bent, distorted and/or missing. See a video on how to use an Amsler grid here:  and watch an animation showing the Amsler grid with macular degeneration here: .

Macular degeneration by itself will not lead to total blindness. For that matter, only a very small number of people with visual impairment are totally blind. In almost all cases, some vision remains. Other complicating conditions may possibly lead to such an acute condition (severe stroke or trauma, untreated glaucoma, etc.), but few macular degeneration patients experience total visual loss. The area of the macula comprises about 5% of the retina and is responsible for about 35% of the visual field. The remaining 65% (the peripheral field) remains unaffected by the disease

The loss of central vision profoundly affects visual functioning. It is not possible, for example, to read without central vision. Pictures which attempt to depict the central visual loss of macular degeneration with a black spot do not really do justice to the devastating nature of the visual loss. This can be demonstrated by printing letters 6 inches high on a piece of paper and attempting to identify them while looking straight ahead and holding the paper slightly to the side. Most people find this surprisingly difficult to do.

There is a loss off contrast sensitivity, so that contours, shadows and color vision are less vivid. The loss in contrast sensitivity can be quickly and easily measured by a contrast sensitivity test performed either at home or by an eye specialist.

Similar symptoms with a very different etiology and different treatment can be caused by Epiretinal membrane or macular pucker or leaking blood vessels in the eye..

When to see a doctor
See your eye doctor — particularly after age 50 — if:

* You notice changes in your central vision
* Your ability to see colors and fine detail becomes impaired

One way to monitor your eyes to determine if you may need to visit your eye doctor is to check your vision regularly using an Amsler grid. This simple test may help you detect changes in your sight that you otherwise may not notice.

Here’s how to perform the test:

* Hold the grid 14 inches (about 36 centimeters) in front of you in good light. Use your corrective glasses or reading glasses if you normally wear them.
* Cover one eye.
* Look directly at the center dot with your uncovered eye.
* While looking at this dot, determine whether all of the lines of the grid appear straight, uninterrupted and have the same contrast.
* Repeat the above steps with your other eye.
* If any part of the grid is missing or looks wavy, blurred or dark, contact your eye doctor immediately.

Causes:
The exact cause of dry macular degeneration is unknown, but the condition develops as the eye ages. The initial site of change is not in the light-sensitive cells of the macula, but in the retinal pigment epithelium (RPE), a single layer of cells located just behind the retina close to the back wall of your eye.

Your macula is an area about two-tenths of an inch (5 millimeters) in diameter at the center of your retina. This small part of your eye is responsible for clear vision, particularly in your direct line of sight.

The macula consists of millions of densely packed light-sensitive cells called cones and rods. Cones and rods have two segments: An inner segment controls cell functions and produces proteins responsive to light, and an outer segment stores and makes use of these proteins.

As they absorb light, outer segment proteins become degraded and eventually are shed as waste. Meanwhile, the inner segments continuously provide replacements for the outer segments. One function of the cells of the RPE is to remove the outer segments that are shed.

As the eye ages, cells in the RPE begin to deteriorate (atrophy) and lose their pigment. As a consequence, the RPE becomes less efficient in removing outer segment waste. When that happens, the normally uniform reddish color of the macula (as seen with an ophthalmoscope) takes on a mottled appearance. Drusen — yellow, fat-like deposits — begin to appear under the cones and rods. As the drusen and mottled pigmentation continue to develop, your vision gradually deteriorates.

Based on this progression, dry macular degeneration is categorized in three stages:

* Early stage. Several small drusen or a few medium-sized drusen are detected on the macula in one or both eyes. Generally, there’s no vision loss in the earliest stage.
* Intermediate stage. Many medium-sized drusen or one or more large drusen are detected in one or both eyes. At this stage, your central vision may start to blur and you may need extra light for reading or doing detail work.
* Advanced stage. Several large drusen, as well as extensive breakdown of light-sensitive cells in the macula, are detected. These features cause a well-defined spot of blurring in your central vision. The blurred area may become larger and more opaque over time.

Macular degeneration almost always starts out as the dry form. Dry macular degeneration may initially affect only one eye but, in most cases, both eyes eventually become involved.

Risk factors:
Contributing factors for development of macular degeneration include:

* Age. In the United States, macular degeneration is the leading cause of severe vision loss in people age 60 and older.
* Family history of macular degeneration. If someone in your family had macular degeneration, your odds of developing macular degeneration are higher. In recent years, researchers have identified some of the genes associated with macular degeneration. In the future, genetic screening tests may be helpful for assessing early risk of the disease.
* Race. Macular degeneration is more common in whites than it is in other groups, especially after age 75.
* Sex. Women are more likely than men to develop macular degeneration, and because they tend to live longer, women are more likely to experience the effects of severe vision loss from the disease.
* Cigarette smoking. Exposure to cigarette smoke doubles your risk of macular degeneration. Cigarette smoking is the single most preventable cause of macular degeneration.
*Stargardt’s disease (STGD, also known as Juvenile Macular Degeneration) is an autosomal recessive retinal disorder characterized by a juvenile-onset macular dystrophy, alterations of the peripheral retina, and subretinal deposition of lipofuscin-like material. A gene encoding an ATP-binding cassette (ABC) transporter was mapped to the 2-cM (centiMorgan) interval at 1p13-p21 previously shown by linkage analysis to harbor the STGD gene. This gene, ABCR, is expressed exclusively and at high levels in the retina, in rod but not cone photoreceptors, as detected by in situ hybridization. Mutational analysis of ABCR in STGD families revealed a total of 19 different mutations including homozygous mutations in two families with consanguineous parentage. These data indicate that ABCR is the causal gene of STGD/FFM.
*Drusen CMSD studies indicate that drusen are similar in molecular composition to plaques and deposits in other age-related diseases such as Alzheimer’s disease and atherosclerosis.
While there is a tendency for drusen to be blamed for the progressive loss of vision, drusen deposits can, however, be present in the retina without vision loss. Some patients with large deposits of drusen have normal visual acuity. If normal retinal reception and image transmission are sometimes possible in a retina when high concentrations of drusen are present, then even if drusen can be implicated in the loss of visual function, there must be at least one other factor that accounts for the loss of vision. Retinitis Pigmentosa (RP) is a genetically linked dysfunction of the retina and is related to mutation of the ATP Synthase Gene 63.
* Obesity. Being severely overweight increases the chance that early or intermediate macular degeneration will progress to the more severe form of the disease.
* Light-colored eyes. People with light-colored eyes appear to be at greater risk than do those with darker eyes.
* Exposure to sunlight. Although the retina is more sensitive to shorter wavelengths of light, including ultraviolet (UV) light, only a small percentage of ultraviolet light actually reaches the retina. Most ultraviolet light is filtered by the transparent outer surface of your eye (cornea) and the natural crystalline lens in your eye. Some experts believe that long-term exposure to ultraviolet light may increase your risk of developing macular degeneration, but this risk has not been proved and remains controversial.
* Low levels of nutrients. This includes low blood levels of minerals, such as zinc, and of antioxidant vitamins, such as A, C and E. Antioxidants may protect your cells from oxygen damage (oxidation), which may partially be responsible for the effects of aging and for the development of certain diseases such as macular degeneration.
* Cardiovascular diseases. These include high blood pressure, stroke, heart attack and coronary artery disease with chest pain (angina).
*High fat intake is associated with an increased risk of macular degeneration in both women and men. Fat provides about 42% of the food energy in the average American diet. A diet that derives closer to 20-25% of total food energy from fat is probably healthier. Reducing fat intake to this level means cutting down greatly on consumption of red meats and high-fat dairy products such as whole milk, cheese, and butter. Eating more cold-water fish (at least twice weekly), rather than red meats, and eating any type of nuts may help macular degeneration patients.
*Oxidative stress: It has been proposed that age related accumulation of low molecular weight, phototoxic, pro-oxidant melanin oligomers within lysosomes in the retinal pigment epithelium may be partly responsible for decreasing the digestive rate of photoreceptor outer rod segments (POS) by the RPE. A decrease in the digestive rate of POS has been shown to be associated with lipofuscin formation – a classic sign associated with macular degeneration.
*Fibulin-5 mutation Rare forms of the disease are caused by geneic defects in fibulin-5, in an autosomal dominant manner. In 2004 Stone et al. performed a screen on 402 AMD patients and revealed a statistically significant correlation between mutations in Fibulin-5 and incidence of the disease. Furthermore the point mutants were found in the Calcium binding sites of the cbEGF domains of the protein. there is no structural basis for the effects of the mutations.

Diagnosis:
Diagnostic tests for macular degeneration may include:

*An eye examination. One of the things your eye doctor looks for while examining the inside of your eye is the presence of drusen and mottled pigmentation in the macula. The eye examination includes a simple test of your central vision and may include testing with an Amsler grid. If you have macular degeneration, when you look at the grid some of the straight lines may seem faded, broken or distorted. By noting where the break or distortion occurs — usually on or near the center of the grid — your eye doctor can better determine the location and extent of your macular damage.

Regular screening examinations can detect early signs of macular degeneration before the disease leads to vision loss.
*Angiography. To evaluate the extent of the damage from macular degeneration, your eye doctor may use fluorescein angiography. In this procedure, fluorescein dye is injected into a vein in your arm and photographs are taken of the back of the eye as the dye passes through blood vessels in your retina and choroid. Your doctor then uses these photographs to detect changes in macular pigmentation or to identify small macular blood vessels.

Your doctor may also suggest a similar procedure called indocyanine green angiography. Instead of fluorescein, a dye called indocyanine green is used. This test provides information that complements the findings obtained through fluorescein angiography.
* Optical coherence tomography. This noninvasive imaging test helps identify and display areas of retinal thickening or thinning. Such changes are associated with macular degeneration. This test can also reveal the presence of abnormal fluid in and under the retina or the RPE. It’s often used to help monitor the response of the retina to macular degeneration treatments.

Treatment:
There’s no treatment available to reverse dry macular degeneration. But this doesn’t mean you’ll eventually lose all of your sight. Dry macular degeneration usually progresses slowly, and many people with the condition are able to live relatively normal, productive lives, especially if only one eye is affected. Dry macular degeneration can, however, develop into the more rapidly progressive wet type of macular degeneration at any time.

Taking a high-dose formulation of antioxidants and zinc may reduce progression of dry macular degeneration to advanced macular degeneration. The National Eye Institute-sponsored Age-Related Eye Disease Study (AREDS) showed that a daily supplement of 500 milligrams (mg) of vitamin C, 400 international units (IU) of vitamin E, 15 mg of beta carotene (often as vitamin A — up to 25,000 IU), 80 mg of zinc (as zinc oxide) and 2 mg of copper (as cupric oxide) reduced the risk of progressing to moderate or severe vision loss by up to 25 percent.

Life Style & Home Remedies:
Macular degeneration doesn’t affect your side (peripheral) vision and usually doesn’t cause total blindness. But it can rob you of your central vision — which is important for driving, reading and recognizing people’s faces. A low-vision center may be able to assess your visual capabilities and suggest certain optical and household devices that can be helpful for some near-vision tasks. Ask your eye doctor if there are any low-vision centers in your area.

There are ways to cope with impaired vision. Below are a few suggestions:

* Use caution when driving. First, check with your doctor to see if driving is still safe based on your current visual acuity. When you do drive, there are certain situations to avoid. For example, don’t drive at night, in heavy traffic or in bad weather.
* Seek help traveling. Use public transportation or ask family members to help, especially with night driving.
* Travel with others. Contact your local area agency on aging for a list of vans and shuttles, volunteer driving networks or ride shares.
* Get good glasses. Optimize the vision you have with the right glasses, and keep an extra pair in the car.
* Use magnifiers. Large-print books and magazines can help you read more easily.
* View with large type on the Internet. Look for Web sites that use large-sized type fonts, or change the font size on your display.
* Obtain specialized appliances. Some clocks, radios, telephones and other appliances have extra-large numbers.
* Have proper light in your home. This will help with reading and other activities.
* Remove home hazards. Eliminate throw rugs and other possible tripping hazards in your home.
* Ask friends and family members for help. Tell them about your vision problems so that they can help you perform certain tasks and help you recognize people.
* Don’t become socially isolated. A common frustration of people with macular degeneration is the inability to recognize other people and greet them by name. If this happens to you, try asking people you know to say hi and tell you their names when you meet them on the street or in other situations so that you can greet them back.
* Take advantage of online networks. The Internet is a good source for support groups and resources for people with macular degeneration.

Alternative Medicine:
Some people have turned to complementary or alternative therapies, such as bilberry, ginkgo and shark cartilage, in the belief that they can help prevent the progression of macular degeneration.

However, there’s no conclusive evidence that any of these products are effective for macular degeneration, and some may interact with other medications you’re taking. Check with your doctor before taking any dietary or herbal supplement.

Prevention
The Age-Related Eye Disease Study showed that a combination of high-dose beta-carotene, vitamin C, vitamin E, and zinc can reduce the risk of progressing from early to advanced AMD by about 25 percent.  Studies are underway with the goal of reducing lipofuscin accumulation.

Studies have found that Lutein and zeaxanthin (Carotenoid nutrients found in green vegetables such as Kale, Spinach, Collards, spices such as Saffron, and egg yolk) protect against and possibly reverse macular degeneration and Retinitis pigmentosa.  Studies found that antioxidants disrupt the link of two processes that cause macular degeneration and extend the lifetime of irreplaceable photoreceptors and other retinal cells (Lutein is known to have antioxidant properties).

Eating spinach or collard greens five times a week decreases the risk of AMD by 43%

Studies reported in the British Journal of Ophthalmology suggest that while beneficial for those in advanced stages, antioxidant supplements can be counterproductive for people with early stages of AMD as antioxidants can potentially negate the beneficial effects of Omega-3 fats. It has been found that Omega-3 fatty acids can prevent or even halt the progress of degeneration. However, moderation of oily fishes in patients’ diets is suggested as they can lead to a build up of pollutants such fishes may contain.

The following measures may help you avoid macular degeneration:
*Eat foods containing antioxidants.
*Take antioxidant and zinc supplements.
* Eat fish.
*Stop smoking.
*Manage your other diseases.
*Get regular eye exams.
*Screen your vision regularly.

If you have some vision loss because of macular degeneration, your eye doctor can prescribe optical devices called low-vision aids that will help you see better for close-up work. Or your doctor may refer you to a low-vision specialist. In addition, a wide variety of support services and rehabilitation programs are available that may help you adjust your lifestyle.
Impact:
Macular degeneration can advance to legal blindness and inability to drive. It can also result in difficulty or inability to read or see faces.

Adaptive devices can help people read. These include magnifying glasses, special eyeglass lenses, desktop and portable electronic devices, and computer screen readers such as JAWS for Windows.

Composer Josef Tal checks a manuscript (2006)Accessible publishing also aims to provide a variety of fonts and formats for published books to make reading easier. This includes much larger fonts for printed books, patterns to make tracking easier, audiobooks and DAISY books with both text and audio.

Because the peripheral vision is not affected, people with macular degeneration can learn to use their remaining vision to continue most activities. Assistance and resources are available in every country and every state in the U.S. Classes for “independent living” are given and some technology can be obtained from a state department of rehabilitation. You can also search for macular degeneration on the internet and contact one of the non-profit organizations for assistance.

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.mayoclinic.com/health/macular-degeneration/DS00284
http://en.wikipedia.org/wiki/Macular_degeneration

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Fluorescein Angiography (Test for Diabetic Retinopathy)

Alternative Names: Retinal photography; Eye angiography

Definition:
Fluorescein angiography is an eye test that uses an special dye and camera to look at blood flow in the retina and choroid……...CLICK & SEE

By looking into the back of your eye (the retina), eye doctors can see changes in the blood vessels there that show whether you are at risk for losing vision from diabetes or other causes. The earliest changes can be seen only with a special test called fluorescein angiography. For this test, a chemical that temporarily makes the blood vessels fluorescent and shows very tiny leaks in them is injected into one of your arm or hand veins while you are having your eyes examined.

This test is used to determine if there is proper circulation in the blood vessels of the retina. It can also be used to diagnose problems in the eye or to determine how well treatment is working.

Preparation  for the test:
You should arrange to have someone else drive you home from the eye doctor, because your eyes will be dilated; this can make your eyes sensitive to the sun and your vision blurry for a while.

You may be told to discontinue drugs that could affect the test. results. Tell your health care provide about any allergies, particularly reactions to iodine.

You must sign an informed consent form. You must remove contact lenses before the test.

Tell the health care provider if you may be pregnant.


How the Test Is Performed

Eye drops that make the pupil dilate will be given. You will be asked to place your chin on a chin rest, and your forehead against a support bar to keep your head still during the test.

Fluorescein angiography->…..CLICK & SEE

The health care provider will take pictures of the inside of your eye. After the first group of pictures are taken, a special dye called fluorescein is injected into your vein, usually at the bend of the elbow. A special camera takes pictures of the dye as it moves through the blood vessels in the back of the eye.

More photographs are taken up to 20 minutes after the injection.

What happens when the test is performed?
You have drops put into your eye to make the pupil dilate (open), and you have to wait for about half an hour while the drops take effect. Before giving you any other medicine, your doctor might first examine your eyes for signs of bleeding or debris outside of your retina arteries; these are signs of more advanced eye disease from diabetes. Then a nurse inserts a small needle into one of the veins in your arm or hand so that you can have a dose of medicine injected. Your doctor uses a special eye camera to take pictures of your retina. You look into one side of the camera while your doctor looks through the other side. The camera shines a dim blue light into your eye, which causes the dye flowing through the retina arteries to show up as fluorescent green. The doctor takes a collection of pictures of your eyes to review more closely later.

This color retinal photograph demonstrates nonproliferative diabetic retinopathy. The image is centered on the macula (the part of the retina responsible for central fine vision) with part of the optic nerve seen on the left of the photo (left eye). There are hemorrhages within the retinal tissue on the right side of the photograph.

How the Test Will Feel
When the needle is inserted , some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

When the dye is injected, you may have mild nausea and a warm sensation. These symptoms are usually very brief.

Normal Results:
A normal result means the vessels appear a normal size and there are no blockages or leakages.
Back to TopWhat Abnormal Results Mean
If blockage or leakage is present, the pictures will map the location for possible treatment.

An abnormal value on a fluorescein angiography may be due to:

*Blood flow (circulatory) problems
*Cancer
*Diabetic or other retinopathy
*Inflammation or edema
*Macular degeneration
*Microaneurysms — enlargement of capillaries in the retina
*Tumors
*Swelling of the optic disc

Additional conditions under which the test may be performed:

Retinal detachment
Retinal vessel occlusion
Retinitis pigmentosa

Risk Factors:
There are no special risks from this test, although your vision may be blurry for an hour or more after the test because your pupils are dilated. The dye fluorescein is excreted from your body in your urine, which might give your urine a bright or discolored appearance for a day.

There is a slight chance of infection any time the skin is broken. Rarely, a person is hypersensitive to the dye and may experience:

*Dizziness or faintness
*Dry mouth or increased salivation
*Hives
*Increased heart rate
*Metallic taste in mouth
*Nausea and vomiting
*Sneezing
*Serious allergic reactions are rare.

Your urine will be darker, and possibly orange in color, for a day or two after the test.

Must you do  after the test is over?

You will need to wear sunglasses for a few hours until your pupils are no longer dilated.

Considerations:
People with cataracts will have less accurate test results.

How long is it before the result of the test is known?
Your doctor can often discuss the results of the test with you at the end of your visit. He or she might recommend treatment (such as eye laser treatments) if your test reveals retina disease.

Click to see:->How does diabetes affect the retina?

Resources:
https://www.health.harvard.edu/diagnostic-tests/fluorescein-angiography.htm
http://health.nytimes.com/health/guides/test/fluorescein-angiography/overview.html

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Scotoma

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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

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