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!

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?

Visual impairment is a decreased ability to see to a degree that causes disabilities or problems, not fixable by usual means, such as glasses. Loss of vision may be acquired and develop suddenly. It may affect one or both your eyes.

What Causes Loss of Vision/Disability?

Loss of vision and disability can result from the following  

Clouding of normally transparent eye structures

Abnormalities in the retina

Abnormalities in the nerves carrying visual signals to the brain from the eyes

Changes in vision may also occur due to conditions like glaucoma, macular degeneration and diabetic retinopathy. 

Can Psychological Rehabilitation Help Manage Visual Impairment?

Vision loss and disability often interfere with one s functional ability in everyday tasks. Sometimes, the disability may be so devastating that it affects a person s mental health and behaviour. Psychological Rehabilitation is designed to help such visually impaired people deal with disability or impairment. 

Psychological rehabilitation involves a wide range of methods that aims to restore functioning after loss of vision, just as physiotherapy restores functioning after an injury or stroke. The program allows patients to continue living independently and maintain their quality of life despite vision loss. 

Complete or partial loss of vision can jeopardize one s career   you may not be able to continue with your job due to the disability.  Many people suffer psychological and physical challenges, which force them to escape the outside world. Psychological rehabilitation helps in the following ways  

Helps individual understand and accept the disability, and find ways to cope with it

Motivates them in to keep trying

Cope with the pain and depression

Overcome feelings of fear or despair

Prevents the person from sinking into a state of self-pity, which may hinder recovery

Rehabilitation Psychology adopts a holistic and expansive approach to treat visual impairment. 




Loss of Vision & Disability - How Can Psychological Rehabilitation Help?

A common headache can have a number of reasons behind it, such as defective vision, hetrophoria or convergence deficiency, etc. Now, the question arises as to how they can cause headache. Read on to know more...

Q. Why should defective vision cause headache?

To attain a perfect vision, eyes with defective vision have to make sustained extra efforts, which results in headache. Even if the refractive error is very small, it can be the cause of headache. More prolonged the working and smaller the print, higher the incidence of headache.

Q. Can this occur at all ages?

Yes, it can occur at all ages. However, with age, the resistance decreases and hence elderly people are more prone to get headache. More the use of computer, mobiles, TV or prolonged studies precipitates headache

Q What is Hetrophoria?

Normally, both eyes always remain parallel, but in some cases, eyes have slight tendency to develop minor squint, may be convergent or divergent. This is called Hetrophoria or Latent squint. Such patients have to take extra strain to keep the eyes straight

Q. What is convergence deficiency?

For reading, both eyes have to converge and if there is weakness of convergence, extra strain has to be put on the eyes, which cause headache.

Q. What is the ideal method of refraction in young patients, I,e below 40 years?

Ideal method is to dilate the pupil with Tropicasyl plus drops. This has the advantage that the doctor can see the retina and Optic Disc. This is important to exclude any involvement of brain as the cause of headache. It also relaxes accommodation and hence provides correct refraction. In cases of Hypermetropia, it is extremely essential to dilate the pupil.

Q. What is the role of Autorefractmeter (a computer) in refraction?

It is a very important instrument to provide correct refraction, but it cannot be totally relied upon. Some opticians rely on it and give wrong numbers.

Q. What is acceptance Test?

You have refracted the eyes with Autorefractmeter or Streak Retinoscope but exact power is what a patient accepts. This is very important.

Q. What is astigmatism?

There is a difference in refraction in different meridians and it is important that a cylinder number is prescribed in correct axis. This is a difficult task and needs lot of experience.

Q. Is it important to correct astigmatism?

To relieve headache and strain on the eyes, it is very important that exact cylinder is prescribed.

Q. What is the role of exact centring of Optical Lenses?

You may give correct number, but if the centre of the Optical lenses and cornea do not coincide, satisfactory results are not obtained. To dispense correct lenses is a big art and the Optician must be qualified and well experienced.

Q. Does the quality of lens affect the visual comfort?

Yes, it is important that quality of lenses should be good, preferable fibre lenses which are Ant reflect coated. Crizal coating with capability to block the UV rays are very popular.

Conclusion: Refractive errors are important cause of headache and needs proper examination of the eyes, preferably after dilating the pupil. Astigmatic error even if too small may be the cause of headache. Spectacle dispensing is an art and a patient must select proper optician. Spectacles if advised for constant use must be used constantly to get full relief.

Defective Vision - Can it be a Cause of Your Headache?

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 quality and sharpness of vision are generally measured with a Snellen chart. The Snellen chart shows letters of logically smaller size. Perfect vision is 20/20. This implies the patient or subject sees the same line of letters at twenty feet that a typical individual sees at twenty feet.

Here are a few doctor recommended tips that can be followed in order to achieve a perfect vision. These are as follows:

1. Eat right for good vision
Taking good care of your eyes begins with the food that you eat. Foods, for example, fatty acids, lutein, zinc and vitamins C and E may avert age related vision and eyesight problems, for example, macular degeneration and cataract as shown by certain studies. Eating these foods daily can lead to healthy eyesight. Following are some of the nutrients that can help us do so:

    Green vegetables, for example, spinach, kale, and collards
    Salmon and fish
    Eggs, nuts, beans, and other non-meat protein sources
    Oranges and different citrus natural products or juices
    Shellfish and pork

2. Quit smoking
Smoking makes you more inclined to get cataract, optic nerve damage and macular degeneration. The more times you attempt to stop smoking, the more probable you are to succeed.

3. Wear shades
The right sort of shades will shield your eyes from the sun's bright (UV) beams. An excess of UV exposure makes you more inclined to get cataracts and macular degeneration. Pick shades that piece ninety nine to hundred percent of both UVA and UVB beams. Wraparound lenses shield your eyes from the side. Spellbound lenses diminish the glare when driving. Some of the contact lenses come with UV protection as well. It is still a smart thought to wear shades for more protection, however.

4. Turn away From the Computer Screen
Gazing at a computer screen for a really long time can bring about eye strain, foggy vision, trouble focusing at a distance, dry eyes. The muscles around the eyes can start getting weak and painful if given too much strain. Turn down the screen brightness. You need to at present have the capacity to see, however, you should not feel like you are gazing at a very bright light. In case you are reading from the computer, use the zoom capacity to make the content bigger.

5. Pencil exercise
Take a pencil, and place it some place in the centre. Draw a letter, number or dot in on any side of the pencil. For this activity, you will concentrate on the pencil and the spot as you move it toward and far from your eyes. Pencil push-ups are rumoured to correct twofold vision and crossed eyes, yet it cannot hurt to attempt them for different issues since it is free, easy, and just includes focusing and refocusing your eyes. 

How to Have the Perfect Vision? Doctor Recommended Tips

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