Amblyopia is commonly known as'lazy eye. It is a vision development disorder, which affects eyes and the brain during infancy and childhood. It signifies that the eye does not achieve a normal visual acuity even with refractive correction in form of glasses or contact lens. During normal visual development, the eye and brain learns to'see' and develop binocularity, that is the ability to perceive depth (stereoacuity). This occurs in the first 8 to 10 years of life. 

Each eye transmits a clear and identical image from retina to the brain, which fuses the two images into a single image with 3 dimensions (adding depth). When the image is formed on the retina of two eyes is too dissimilar, the brain cannot fuse the two images and suppresses the more blurred image. As a result, the worse eye does not learn to'see' and becomes'lazy. This condition is seen in 1-4% of population.

The common causes for dissimilar images or amblyopia are:
1. Misalignment of the eyes or squint: it is the primary reason for amblyopia is misalignment of the eyes. In case, both your eyes are not aimed in the same direction, the image captured by each eye is different, resulting in diplopia. The brain will see from the dominant eye and suppress image from the other eye. Over a prolonged period of time, the eye dissociates from the visual cortex of the brain.

2. Refractive amblyopia:
A. Unequal refractive error in both eye. When the eye power of both eyes differ by more than 1.5d of spherical equivalent, which results in dissimilar images between the two eyes. As a result, the visual development in restricted in the worse eye.
B. High refractive error or astigmatism in both eyes, since there is a blurred image in both eyes, the normal vision development does not occur in either eyes resulting in bilateral lazy eyes.

3. Cloudiness in visual system or visual deprivation amblyopia: any kind of obstruction or cloudiness in the normal visual axis of the eye tissues can lead to amblyopia. Disorder of any kind, which blocks a clear image from being focused blocks the formation of a clear image on your retina. Commonly due to congenital or developmental cataracts or corneal opacities or prolonged closure of one eye in early childhood (drooping of one eyelid, eyelid swelling, patching of one eye).

Treatment for amblyopia
For treatment of amblyopia, a child must be compelled to utilize his affected, weaker eye. This can be done by correction of causative factor such as, treating refractive error with glasses, surgical correction of misalignment of eyes followed by patching and vision therapy, cataract surgery.

Patching or occlusion of the good eye
This is done to force the brain to pay attention to visual input from the worse eye. This allows nerve connections between affected eye and brain to develop due to, which the eye'learns to see. Eye drops such as atropine are also used for blurring the vision of the good eye. Some form of vision therapy may also be required to train both eyes to see together and develop some degree of depth perception.

To be effective, treatment should be implement as early as possible, within the period of normal visual development best within first 8 years of life. Some visual gain has been seen in selected patients up to age of 14 to 18 years. This also highlights the importance of a comprehensive eye examination as a routine in young children.

About Amblyopia or Lazy Eye

Eyeglasses and contact lenses are both used for vision correction. Both of the options have their advantages and disadvantages but a number of factors like lifestyle, comfort and age etc. are important while deciding which one to choose. Here is a list of the fundamental differences between using spectacles and using contact lenses:

1. Distance from the cornea
Lenses are worn directly on the eye and are in constant physical contact with the cornea while glasses are worn over the eyes. Contact lenses may cause infections in the eye because the user has to touch the eye in order to wear them and to take them off.

2. Difference in vision
Since the lenses of spectacles are a little distance away from the eye, vision can be slightly distorted but contact lenses can provide natural and accurate vision. Also, side vision is not improved by glasses as you have to turn your head to see what is beside you. The contacts move around with your eyeballs and the peripheral vision is in focus.

3. Ease of use
Some people find eyeglasses difficult to use because of the constant weight on the face and the obstruction caused by the frames of the glasses. There may also be a constant need to adjust the frames. Often eyeglasses slip down the nose when you sweat or engage in rigorous physical activity. Contact lenses are free from all these hassles - they are not distracting or obstructive and so they are extensively used by dancers and athletes. Spectacles is very uncomfortable to wear during the rains or in humid weather because they fog up.

4. Infections and complications
Contact lenses can get displaced inside the eye and they can be difficult to reposition. They also cause the eyes to itch and water if you wear them for a very long time at a stretch or if tiny dust particles enter your eyes. The use of eyeglasses is far more flexible in this respect - they can be removed in case your eye itches or burns, but regular use of glasses causes dark circles and bags under the eyes.

5. Aesthetic differences
People often prefer contact lenses as they do not change the physical appearance - they help you look natural and you can also use colored lenses to change the color of your eyes. Glasses may look slightly unnatural but some people also prefer them for the fashion quotient.

Lens Vs Specs

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?

5 myths about eye health and the real facts behind them

Your eyes are an important part of your health. There are many things you can do to keep them healthy and make sure you are seeing your best. However, there are a number of myths regarding what you should do and what you shouldn't do when it comes to maintaining good eye health.

Here are 5 of those myths busted:

Myth #1: reading in dim light and sitting too close to the tv hurts your eyes

Fact: sitting too close to the tv, you may feel eye strain or get a headache from reading in the dark, but it will not weaken your eyes. It fatigues your eyes but does not harm your eye health in any way.

Myth #2: eating carrots will improve your vision

Fact: carrots are rich in vitamin a, a nutrient essential for good vision. But eating carrots will only provide a small amount of vitamin a. To get the optimum amount, you need to include other sources of vitamin a in your diet as well, some of which are milk, cheese, egg yolk and liver. Spinach is best for eye health. It has lutein and zeaxanthin, both of which can help prevent cataracts.

Myth #3: if you wear glasses or contacts for a continuous period, your eyes will weaken

Fact: your eyes will not grow weaker by using corrective lenses. The prescription may change over time due to aging or absence of disease but it has nothing to do with your current prescription. Some children have correctable eye problems that do require glasses to improve the condition.

Myth #4: when you get something in your eye, rub it out

Fact: this is not true for everything that gets in your eyes. If any particle falls in your eyes dust it off. But if it is sand and small debris that gets in your eye, don't touch it. Use an eye wash for flushing it out. If an object gets stuck in your eye, don't remove it or rub your eye constantly. Visit a doctor at the earliest because some serious injuries may seem minor at first.

Myth #5: dark sunglasses can protect your eyes from the sun

Fact: the color of sunglass does not ensure eye protection. Look for sunglasses that block both uva and UVB rays. Exposure to the UV-rays of sunlight can have cumulative effects on your eyes. It increases your risk for cataracts, solar retinitis, and age-related vision loss. Even if your contacts have UV protection, wear sunglasses that block 100% of uva and UVB rays for full protection.

If you would like to consult with me privately, please click on 'consult'.
Related Tip: Here's What CRYING Does to Your Body

Sitting Too Close To TV Will Weaken Your Eyes? FALSE.

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?

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!

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