People may suffer from visual impairment even though their eyes are perfectly normal. Such loss of vision may result from neurological impairment.

Vision is the combination of image formation and perception of various attributes of the image by the brain. When the brain is not able to perceive images or various attributes of images, the patient may suffer from neurological impairment of vision. Such impairment owes its origin to the nervous system.

Causes of Visual Impairment:

There are various areas in the brain that process some or the other attribute of the image that has formed on the retina. Occipital cortex, the area situated at the rear side of the brain is a very important site. It is responsible for processing visual stimuli and allowing people to make an idea about shape, distance, movement, color, etc. The severity of loss of vision depends on the extent and location of damage in the brain.

Neurological loss of vision may result from acquired brain injury, difficulties with visual perception, impairment in coordination of the eyes, etc. All these may stem from damage areas in the brain that are responsible for vision. There are many areas in the brain that are responsible for vision.

These areas can get damaged from various accidents like:

Stroke: If a person suffers a stroke, a part of his or her brain is likely to get damaged due to a haemorrhage or a blocked blood vessel.

Traumatic Brain Injury: A traumatic brain injury such as in a car accident or a violent fall can damage visual perception of the brain.

Infections: Infections such as meningitis attack the brain and may impair various areas of it.

Lack of Oxygen: People may suffer from lack of oxygen if they experience accidents like a near-drowning episode or a heart attack or something else, which has the effect of interrupting blood flow to the brain.

Diseases: Diseases such as brain tumors, multiple sclerosis etc. can precipitate neurological vision loss.

Symptoms of Visual Impairment:

Symptoms of neurological vision loss depend on the type of vision impairment and the location of damage in the brain. It may include:

Blurry vision: In Blurry vision, a person will not see things clearly or may see something in light but find it difficult to see them in dim light.

Double vision: In double vision, the patient sees a single object as two and cannot merge them as one.

Problems with depth perception of objects

Problem with bright light: In this type of problem, a person experiences difficulty seeing an object in a bright light. One may also feel pain or discomfort in the eye in bright light.

Difficulty with interpreting the object the person is looking at

Partial loss in the visual field: In this problem, half of the visual field in each eye is missing.

Treatment of Visual Impairment:

There is hardly any treatment for such vision loss since the rectification of visual acuity is of no help. Depending on the location and degree of neurological impairment, vision may improve over time. Some children with acquired brain injury or impairment in the coordination of the eyes and difficulties with visual perception also tend to improve with age.

Conclusion:

This is a type of vision loss where glasses, contact lenses, surgeries, or eye drops are not going to help. Such vision loss is usually permanent. Children with similar symptoms need to be presented with pictures, bright light, etc., which may help to form an idea about the object.

Visual Impairment Related To Nervous System!

Are you losing your sight day by day? Does it make difficult to see you at night? Is this the onset of Blindness? Get to know about Retinitis Pigmentosa with these tips.

What actually is Retinitis Pigmentosa? 
Retinitis Pigmentosa (RP) refers to a group of diseases, which causes a slow, but progressive vision loss. It is a genetic disorder that affects the ability to respond to light.This inherited disease causes a slow loss of vision, beginning with decreased night vision and loss of peripheral (side) vision and eventually results in blindness.

Causes:
Retinitis pigmentosa is often hereditary (runs in families). If you or your partner has retinitis pigmentosa, there may be up to a 50 percent chance that you will pass it on to your children. Ask your ophthalmologist about genetic counseling if you are planning to have children.

Symptoms:
1. Slow loss of vision
2. Beginning of decreased night vision
3. Loss of peripheral vision
4. Difficulty in identifying colours

Diagnosis:
If you have poor night vision or a loss of side vision or if there is a history of retinitis pigmentosa in your family, your ophthalmologist will conduct a comprehensive eye exam to determine if you have retinitis pigmentosa. Your ophthalmologist will dilate your eyes to look at the back of them for signs of disease.

Treatment:
Currently there is no known cure for retinitis pigmentosa. However, research has shown that vitamin A palmitate may slow the progression of certain forms of RP. Your ophthalmologist can advise you about the risks and benefits of vitamin A palmitate and how much you can safely take. Taking too much vitamin A palmitate can be toxic, and evidence of vitamin A palmitate effect on RP progression is not substantial.
Another recommendation for slowing vision loss from RP is to wear sunglasses to protect your retina from harmful ultraviolet (UV) light.

Retinal prosthesis is also an important area of exploration because the prosthesis, a man-made device intended to replace a damaged body part, can be designed to take over the function of the lost photoreceptors by electrically stimulating the remaining healthy cells of the retina.

Retinitis Pigmentosa: What You Should Know About It?

Cataract is clouding of clear natural lens present inside the eye, this is a major cause of decreased vision in elderly. Cataracts can occur in one or both eyes, usually developing very slowly. Things look blurry, hazy, less colourful and less sharp with cataract. 

Most cataracts are related to ageing, however many other factors can either increase the rate of formation or cause cataract formation. 

Causes of Cataract Formation-

Ageing: Most common cause. As the proteins present in the lens of the eye degenerates over the years ( just like any other organ) cataract is formed. If you are having Diabetes or hypertension, the rate of formation gets accelerated.

Radiation: Prolonged exposure to ultraviolet rays, especially UV-B rays, results in cataract in your eyes. Wearing sunglasses in the daytime helps in slowing down the process of cataract.

Genes: Many genetic disorders can result in congenital cataract ( cataracts present since birth) or early formation. Like in Lowe syndrome or Down's syndrome. 

Lifestyle Choices: Cigarette smoking, long hours of sun exposure regularly, antioxidant, poor diet etc. are responsible for the onset of cataract.

How To Detect Cataract?

Certain signs and symptoms suggest the existence of cataract in the eye. Depending on the type and level of cataract, problems in vision occurs. The main symptom is foggy cloudy vision as if seeing through a dirty glass window. 

Other Symptoms are- 

inability to see clearly in bright light (during the day) which becomes better in dim light ( evening and night) and vice versa. 
watery, tired eyes - mild pain in and around eyes. 
yellow tinge in vision 
Halos around light bulbs or bright light. 
If you are experiencing above symptoms and having problems in viewing things clearly, visit an ophthalmologist and get your eyes checked.

Foggy and Cloudy Vision - A Sign Of Cataract?

Night blindness is also called nyctalopia.It's a type of vision impairment. People with night blindness experience poor vision at night or in dimly lit environments. It is not a disease in itself, but rather a symptom of an underlying problem, usually a retina problem.

What Causes Night Blindness?
A number of eye conditions can cause night blindness, including:
1. Nearsightedness or blurred vision when looking at faraway objects.
2. Cataracts or clouding of the eye's lens.
3. Retinitis pigmentosa, which occurs when dark pigment collects in your retina and creates tunnel vision.
4. Vitamin A Deficiency
5. Zinc Deficiency
6. Dry Eyes
7. Diabetes

Are the Symptoms of Night Blindness?
The sole symptom of night blindness is difficulty seeing in the dark. You're more likely to experience night blindness when your eyes transition from a bright environment to an area of low light, such as when you leave a sunny sidewalk to enter a dimly lit restaurant. You're likely to experience poor vision when driving due to the intermittent brightness of headlights and streetlights on the road.

How can I Prevent Night Blindness?
You can't prevent night blindness that's the result of birth defects or genetic conditions, such as Usher syndrome. You can, however, properly monitor your blood sugar level and eat a balanced diet to make night blindness less likely. 

Orange colored foods are excellent sources of vitamin A, including:
1. Cantaloupes
2. Sweet potatoes
3. Carrots
4. Pumpkins
5. Butternut squash
6. Mangoes

What are the Treatment Options for Night Blindness?
The treatment will depend on its causes.
1. Nutrient deficiency (Vitamin A and Zinc) is the easiest to treat. 
2. If the cause is cataract, you can go for cataract surgery to remove the clouded lens and replace it with artificial intraocular lens. Vision is usually dramatically improved after surgery. 
3. For dry eye syndrome, lubricate your eyes with artificial tear drops as they provide instant relief. Just make sure that they are without preservatives. 
4. Diabetic retinopathy can be prevented with tight control over blood sugar, active lifestyle and good dietary habits.
5. As for retinitis pigmentosa, unfortunately there are no treatments available. Thankfully, new research is showing that vitamin A might have a slowing effect on the progression of this eye disease.

Night Blindness: Causes and Symptoms

The most common vision problems are shortsightedness and farsightedness. Shortsightedness is when a person sees close objects clearly while distant objects appear blurry. It is more common than farsightedness and affects about 70% of the Asian population.

When there is a refractive issue, the prescription usually has a plus/minus with it and also a number. A  minus  symbol is used to represent shortsightedness; the greater the number of the glasses, the higher the shortsightedness. High myopia is a more severe form of shortsightedness where the power is -6.0 or higher.

Symptoms: 

As mentioned, the person will be able to see nearby objects but will have difficulty seeing far off objects.

Difficulty reading signs and boards
Squinting
Straining to reduce the strain on the eye
Tired and fatigue due to this eye strain, especially when in constant move like playing sports or travelling
How it happens?

Vision can be explained by a physical process where light passes through a lens and falls on the retina in the posterior portion of the eye where it forms an image. This is then sent to the brain where it is read and interpreted as a particular object. When the lens becomes elongated, the image that is formed is distorted in that it is formed in front of the retina and not on the retina. Though it gradually settles down with adulthood, in most cases, it progresses and requires corrective lenses. The corrective lenses ensure the image falls on the retina and visual perception is improved.

Treatment:

Corrective glasses are the most commonly used measure for nearsightedness. The lenses could be used either as spectacles or as contact lenses.
Laser surgery can also be used to correct the problem. A thin layer of the cornea is removed and the image formation is corrected.
Artificial intraocular lenses are also being used to treat this condition. They work like contact lenses and may need periodic replacement.
The most common technique, especially for high myopia is the use of surgery to correct the problem. This is a one-time correction and is a more durable solution than the earlier mentioned options.
Appropriate calculations are done to identify the lens to be used so that proper vision is restored.
Complications: 

Though not common, retinal detachment and variable postoperative refractive error can occur during the surgery.
It is very important to set realistic expectations with the patient in terms of what to expect before, during, and after surgery. If only one eye is going for repair, the chances of mismatch in vision could be present in the early stages. Being clear about what to expect will help in successful correction.

Myopia or Nearsightedness - How It Can Be Treated?

Blurred vision is most often a sign that you need corrective spectacles for near sightedness, far sightedness or astigmatism but it could also be a sign of a bigger problem including eye diseases or neurological problems. Blurred vision involves the loss of sharpness of vision and objects appearing hazy and out of focus. It can affect one eye or both eyes simultaneously.

Whatever be your age, it is a good idea to consult a doctor as you begin to experience a blurred vision. To measure the extent of your vision problem, a doctor will do a comprehensive eye examination including spatial contrast sensitivity and a standard eye chart test. Some of the factors that trigger blurred vision are:

1. Myopia or nearsightedness
2. Hypermetropia or farsightedness
3. Astigmatism caused by an irregularly shaped cornea
4. Presbyopia - the diminished ability to focus on objects due to the hardening of the lens in the eye
5. Dry eyes or the lack of lubrication on the surface of the eyes
6. Hormonal changes during pregnancy
7. Migraine headaches
8. Temporary floaters in the eye formed by the liquefying of the gel in the eyes
9. After effects of lasik surgery
10. Eye drops or medication
11. Overuse of contact lenses
12. Diabetes

Blurred vision can also be a symptom of a serious condition such as cataract, glaucoma, macular degeneration, diabetic retinopathy and cardiovascular diseases.

Treatment for blurred vision depends on the factors triggering it. Wearing corrective glasses can cure blurred vision caused by myopia, hypermetropia and astigmatism. These conditions can also be treated by lasik surgery. For blurred vision related to diabetes, check your blood sugar and get it into its optimal range.

Exercises for the eye muscles can also help sharpen vision and lower the rate of eye muscle degeneration. Some of these exercises are:

1. Alternately focus on an object close to you and another far from you for ten seconds each.
2. Blink your eyes and hold for two seconds
3. Roll your eyes clockwise and anticlockwise. Repeat 15-20 times.
4. Rub your palms together to generate heat and place over your eyes to relax them.

A healthy diet with plenty of vitamin a can help keep your eyes healthy and prevent blurring of vision. Wearing sunglasses can also protect your eyes from harmful uv radiation and lower their rate of wear and tear. Lastly avoid reading in moving vehicles and holding a book too close to your face.

Is Your Vision Blurry? What Should You Do?

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