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!

LASIK stands for Laser In-situ Keratomileusis. This is a common eye surgery that helps in correcting vision problems. During this procedure, the cornea of the eye is cut across by a medical expert to raise the tissues and reshape them to correct vision. LASIK is suitable for patients who have shortsightedness, long sightedness or who suffer from astigmatism.

Here are the 5 benefits that a LASIK surgery offers:

1. Improved vision

A study reveals that 95% of the people who underwent this surgery achieved uncorrected visual acuity of 20/40 and 85% of the people achieved 20/20 vision. This procedure ensures that a patient achieves enhanced vision.

2. Quick results and recovery

This surgery enables you to return to your normal schedule immediately the day after the surgery. You can have clear and improved vision within a day.

3. Long- lasting outcomes

A minimum timeframe of 3 months is required for the eyes to adjust, after which LASIK results are permanently noticeable in a patient. No follow up procedures are required unless something wrong went with the surgery. The patient will continue to have improved vision unless there is any normal loss due to illness or aging.

4. No need of glasses

You no longer require glasses as your vision turns to normal post-LASIK surgery.

5. Goodbye contact lenses

LASIK surgery will help eliminate the need for contacts. You will be able to avoid all the problems pertaining to wearing a contact lens, including lens solution.

5 Benefits of Lasik Surgery

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?

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?

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?

A person is said to have great vision more in the metaphorical way than in the literal sense. However, having both is just so important, especially as the ability to see reduces as a person gets older. Old age comes with its own set of problems, and vision loss is one of them. If kept in check from an early age, however, vision loss can be deferred indefinitely.

While a person's eyesight is likely to deteriorate over the course of his life, there is a lot which can be done in an effort to make sure that this is not the case. To start with, it makes good sense to be regular with eye check-ups. After a person attains the age of sixty, he or she should have a doctor take a look at his or her eyes on a yearly basis. There is no point trying to conserve eye sight if a person is too late in taking corrective action. By paying a visit to the ophthalmologist, a person will get to know the exact problem that he is suffering from.

A good diet which is rich in the nutrients which improve a person's eye sight does go a very long way in the long run. A person should make sure that is diverse enough to take care of the needs of a person and should include grapefruit, strawberries as well as berries and nuts.

One of the main things which can be done in order to preserve the health of a person's eyes until he or she reaches an advanced age is to stop smoking in all forms. As a matter of fact, tobacco leads to cyanide entering the blood stream and this does a lot of damage to the eyes. In fact, quite a few irreversible conditions of the eye are caused due to this.

Exercise is said to be good for a person at any age for a variety of reasons and it is really good for even the eyes, though the link may not be immediately so clear. It reduces the risk of age related degeneration by up to 70 per cent!

What is really interesting about a person's eyes is that they can be signs of trouble in other parts of the body. For example, if a person has blurry vision, they should get checked for diabetes. Also, eyes which do not produce enough natural lubrication can show a risk of rheumatoid arthritis and perhaps even thyroid disease.

All in all, a person's eyesight is so crucial to his or her overall health and wellbeing. We have only one pair of eyes, so we might as well take care of them!

Tips to Prevent Vision Loss in Elderly People

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