People may have weak eyes due to a variety of reasons. Astigmatism happens to be one of those reasons. When one is affected by astigmatism, it results in blurry vision. The eye has a part called the cornea, which is the outermost layer of the eye and is responsible for allowing light to enter. When the cornea is not shaped as it should be, it leads to astigmatism.

However, this is not the only condition under which it can occur. In fact, there are two different types of astigmatism. One is corneal astigmatism which is the result of an odd-shaped cornea. The other is lenticular astigmatism, which occurs when the lens has an incorrect shape. More often than not, people are born with astigmatism. However, there are chances of developing this eye disorder after an eye injury or after an eye disease.

How to diagnose?
There are a few ways in which astigmatism can be diagnosed. 

One of the most popular methods is the visual acuity test. This measures the distance at which a letter is read clearly, as compared to what it should be. 
Another way is by refraction. By placing lenses in front of the eyes, the way they focus light is measured. 
The third way by which astigmatism can be detected is by keratometry, also known as topography. Light is focused on the cornea and the reflection is measured to find the curvature of that area.
Treatment options
The easiest way to go about treating astigmatism is by using corrective lenses. This is usually the method of treatment for people whose astigmatism is not that bad. The lenses could either be a part of spectacles or used as contact lenses. The good part about contact lenses is that the field of view is wider.

Orthokeratology (Ortho-k) works to improve astigmatism by using lenses as well. However, the lenses are of the hard variety. These lenses are useful for corneal astigmatism patients as they reshape the eye. Usually, they are worn while sleeping and most people can have normal vision the next day. However, if one stops using them, the eye goes back to its original state. So, they are not a permanent solution.

Surgery, however, can be a permanent solution to astigmatism. LASIK and PRK are two of the most popular types. RK is also popular, but to a lesser extent. It is good to remember that the risks of surgery should be discussed with a doctor prior to undergoing one.

Astigmatism - Ways They Can Be Diagnosed!

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

Amblyopia or Lazy eye is the eye condition in which vision is reduced and cannot be corrected with glasses or contact lenses. All the images seen by the amblyopic eye are not fully acknowledged by the brain. It always affects only one eye, but may be accompanied with reduction of vision in both eyes. It can cause loss of vision, including loss of depth perception and two-eyed 3D vision. It's treatment can yield improvements at any age, but early detection can offer the best chances for a cure. Recent research has proven that lazy eye treatment can be successful in older children and adults. Comprehensive vision examinations are required for infants, toddlers, and pre-school children for the detection of lazy eye or amblyopia.

When the brain parts related with visual processing do not function properly, problems arise with such visual functions as the perception of movement, depth perception and fine detail (acuity, clear eyesight and sharp vision). Amblyopia is the most prevalent neurological defect of vision in children and adults resulting from developmental problems in the brain. Any interference with clear vision in either eye during the first six years or 'critical' period of visual and brain development can cause a lazy eye.

Constant strabismus or the constant turn of one eye in any direction, be it inward turn or crossed eye is one of common causes of amblyopia. The differences in vision or it's prescription between the two eyes leads to refractive amblyopia. Sometimes congenital disorders or a physical blockage of an eye due to trauma, drooping lids, cataract or a blocked tear duct can also lead to amblyopia. Many parents and children are not aware of any symptoms, as amblyopia usually occurs in one eye only and a lazy eye condition can exist without a noticeable eye turn. The visual acuity tests in addition to the 20/20 eye test charts and eye examination with cycloplegic drops by ophthalmologists are necessary to detect lazy eye.

Vision therapy for the eyes and brain is a highly effective non-surgical treatment for lazy eye. It is a progressive program of vision exercises customized to fit the visual needs of each patient. It is conducted at the clinic and occasionally supplemented with exercises to be done at home or workplace. It improve visual comfort, ease, and efficiency and change how a patient processes or interprets visual information. When considering treatment options, it is important to understand that lazy eye results from neurological deficit or problems in the brain and surgery for lazy eye is performed on the muscles on the outside of the eye. Most of the cases, lazy eye surgery provides cosmetic benefits and does not improve the patient's vision, hence options for vision improvement should be exhausted before eye muscle surgery is considered.

Lazy Eye or Amblyopia - Symptoms and Cure

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 can be defined as the clouding of the natural lenses in the eyes. This is caused by the clumping of protein in the eye lens. Cataract is a common eye disorder and the leading cause of loss of vision in people who are past their fortieth birthday. Cataract can occur in one or both eyes. When diagnosed properly, cataract can be treated with surgery to prevent blindness.

Depending on where and how they develop, there are many types of cataract. The most common amongst these are:

1.        Subcapsular cataract

These occur at the back of the eye lens. Diabetic patients are very susceptible to this kind of cataract.

2.        Nuclear cataract

Yellowish-brown cataract that form in the center of the lens are called nuclear cataract. This is usually seen in cataract caused by ageing.

3.        Cortical cataract

Cataract in the lens cortex are known as cortical cataract. These are wedge shaped and whitish in color. Spokes protruding out of these opaque wedges can be seen moving towards the center of the eye.

4.        Congenital cataract

Though they are not common, babies can also have cataract. Cataract formed at birth or within the first year of a baby's birth are known as congenital cataract.

5.        Secondary cataract

Cataract is one of the known side effects of diabetes and glaucoma. Some steroids and medicines are also linked to cataract.

6.        Traumatic cataract

If your vision becomes cloudy years after an eye injury, it could be a traumatic cataract. It can take several years for this to happen.

7.        Radiation cataract

Exposure to radiation can also lead to cataract. This is seen sometimes in patients who have undergone radiation therapy to fight diseases like cancer.

Though the type of cataract might differ from person to person, the symptoms are usually the same. Some of the common symptoms of cataract are:

1. Blurred vision
2. Reduced night vision
3. Increased sensitivity to light and glare
4. Seeing halos around lights
5. Colors appearing faded
6. Double vision

A reading test is the first step towards diagnosing cataracts. This is followed by tests to measure the eye pressure. Your doctor will also need to dilate the pupil to check the condition of the optic nerves and retina.

Surgery is the safest way to remove a cataract. Surgery is usually recommended when cataract begin inhibiting your daily life such as preventing you from driving, interfering with reading etc.
 
In most cases, this can be done as an outpatient procedure. The earlier it is diagnosed, the easier it is to treat. Hence, if you notice any of the symptoms mentioned above, get your eyes checked at once. The surgery is a day-care surgery only, so a person can go home the same day.

Is Your Vision Clouded? It Could Be Cataracts

Cataract is generally associated with old age. However, in some unfortunate cases, children could be affected by cataract as well. A cataract can be defined as a cloudy or opaque layer that forms on the eye's natural lens that lies behind the iris and the pupil, leading to eventual loss in vision. Cataract can affect children in one eye or both eyes.

Cataract can be a congenital birth defect or can develop as the child grows older. The latter case is known as pediatric cataracts. The exact cause of cataracts in children is not known, but it has been associated with a number of genetic disorders, low birth weight and infections during pregnancy. Traumatic events such as an injury to the eye can also cause cataracts.

The earlier a cataract is diagnosed and treated, the better it is. It is easier to identify a cataract that affects both eyes than a cataract that affects only one eye. If a congenital cataract is not treated in time, the part of the baby's brain used for sight may not develop properly. Hence it is crucial to recognize cataract symptoms.

Here are a few you should look out for:

    Not looking directly or responding to large, colourful objects.
    Not being able to find small objects while crawling.
    Excessive squinting or shielding their eyes to bright sunlight.
    Eyes that do not focus on the same point.
    White reflex instead of a red reflex in photographs.
    Uncontrolled movement of the eye.

Cataracts that are too small to affect sight can be treated with eye drops to dilate the pupil. However, this provides only temporary relief. Surgery is the most preferred form of cataract treatment. This surgery can be performed even in the first few weeks of a baby's life. The child is put under anesthesia and a microsurgical instrument is used to break the lens into small pieces and remove it.

This surgery is followed by the use of lenses or glasses to help the eye regain its power to focus again. In some cases, the lens may be implanted to replace the natural lens. In cases where cataract affects only one eye or one eye is more severely affected than the other, there may be a tendency to develop amblyopia or lazy eye syndrome. In such cases, it becomes necessary to patch the good eye shut and stimulate vision in the eye that has undergone surgery.

Cataract in Children

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