Causes Of Astigmatism

More kids report itchy eyes, docs spy trouble

CHENNAI: Opthalmologists are now seeing more cases of children with distorted vision due to bulging cornea disease, which normally occurs in the late teens.

Keratoconus, a progressive disease, may be mistaken for an allergy as children constantly rub their eyes. Doctors say such children also complain of distorted vision or have constant changes in eye prescriptions. While the condition is usually seen among those in their late teens and early twenties, more recently, it is being spotted in children as young as nine years of age, says Dr Anand Parthasarathy, consultant and head of cornea services at the Vasan Eye Care Hospital group. "Almost 50% of the patients who are diagnosed with this condition in my clinic are in the age group of 12-16 years," he adds. Doctors recommend frequent eye check-ups among children to identify the condition early.While advanced cases may require a corneal transplant called as Keratoplasty, more recently, implantable contact lenses, intra corneal ring segments and increasing the strength of the cornea using ultraviolet rays have been used.

Dr Mohan Rajan, the chairman and medical director of Rajan Eye Care Hospitals, says that the condition is more probable in children who suffer from vernal or seasonal conjunctivitis as a child. "I see this allergy in children as young as five years old and they experience redness and itching. These children may rub their eyes vigorously," he says. "This allergy is seen in Indian children in the summer season," he adds.

While a normal cornea is spherical in shape, the cornea of a person suffering from Keratoconus is conical. Symptoms of the condition also include blurred vision. The afflicted may have problems reading and driving. "Frequent changes in the power of the eye may also be an indication of this condition," says Dr Anand.

Doctors say the causes of the condition are largely unknown and may be genetically caused in some patients. "Till a few years back,we used to dismiss cases of Keratoconus as advanced astigmatism (cylindrical vision). But, now due to the availability of better equipment, the condition is diagnosed in its earlier stages among children," says Dr K Vasantha, director of the regional institute of ophthalmology and government eye hospital in Chennai. "Our youngest Keratoconus patient is 11. Till two years ago, our patients were in the age group of 18-20 years," she says.

What is Astigmatism? | LASIK

Astigmatism is a condition where the cornea has an irregular shape that causes problems with vision. The cornea, the clear covering of the lens and iris, serves as a protection to the eye and helps transmit light thru the eye. The cornea is normally spherical in shape, but those with astigmatism may have their cornea more oval shaped. This oval shaping causes light to scatter instead of focusing to a single point as it passes thru the cornea and results in blurred vision.

If you’ve ever looked at the images produced but those wavy mirrors at carnivals, you will have some idea of how astigmatism can distort your vision.

Astigmatism is characterized by distortions in your field of vision, often noted as the blurring of lines. Astigmatism is also a common cause of eyestrain and headaches, especially with prolonged reading or lengthy sessions at the computer. Astigmatism causes blurring of your vision at all distances, so objects close up and even those far away will be blurred. Often present at birth, astigmatism affects many people, although not all cases are severe enough to require corrective treatment .

This is often a very important section of this particular subject. Astigmatism is usually discovered during routine eye exams when your doctor checks your eye’s refraction and visual acuity using standard eye charts. Refraction is the ability to properly focus light rays on the retina and can be measured in a number of ways. Some doctors will ask a series of questions and conduct a visual acuity test, while others will use a keratoscope or keratometer to measure the curvature and shape of your cornea to determine your degree of astigmatism.

Astigmatism can be corrected thru the use of corrective lenses, involving either glasses or contact lenses. Astigmatism can also be corrected with refractive eye surgery .

Corrective Lenses for Astigmatism

Corrective lenses are a conservative method of dealing with astigmatism. Glasses and contact lenses are able to counter the effects of the irregularly shaped cornea and provide vision considerable improvement.

Ortho-K is an alternative method that uses special contact lenses that actually reshape the cornea. These special lenses are worn only at night and they gradually reshape the cornea by applying pressure in the right way.

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