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Astigmatism

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11.JULY.07
by Dr. Kenneth Onu

– What is Astigmatism?

Astigmatism is a refractive error that induces blurry vision, due to an irregular curvature of the Cornea or Lens of an eye.

– What causes Astigmatism?

In astigmatism, the cornea is said to be shaped more like an egg (elliptical shape) rather than a ball (spherical shape). This reduces the corneas ability to focus light.{{more}}

If the astigmatism is caused by the lens of the eye, due to an uneven curvature of the lens then light is scattered. Both conditions prevent a proper focusing of light on the retina, resulting in a blurry image.

Astigmatism prevents affected patients from observing fine details clearly and minutely. Some affected persons might see vertical lines and objects as leaning and not straight. Astigmatism is very common; one in every three people reportedly suffers from astigmatism. Aging and astigmatism have a very strong correlation – astigmatism is seen to increase with age.

Sometimes, patients with astigmatism do not notice it, because their cases are mild. Severe astigmatism, however, is impossible not to notice because of its many symptoms. The symptoms of a severe case of astigmatism can be: blurry vision, fatigue, headaches, focusing problems and squinting.

– How is Astigmatism diagnosed?

A standard eye examination is capable of revealing the presence and degree of astigmatism in the patient being tested by the ophthalmologist or optometrist..

The curvature of the steepest and flattest meridians on the front surface of the cornea can be measured using a device known as a keratometer.

The ophthalmologist may desire a very accurate estimate of the shape of the cornea.

To achieve this, a corneal topographer is used. Alternatively, the axis and the power of astigmatism may be calculated using a sunburst or a clock dial. An objective representation of the refractive error in the eye may be measured using an autorefractor or retinoscopy. Jackson cross cylinders may be used in a phoropter to refine the measurement of the refractive error subjectively.

– How is Astigmatism treated?

Astigmatism may be treated with the help of corrective eye glasses, corrective contact lenses or refractive eye surgery.

Dr Kenneth Onu is a resident Consultant Ophthalmologist at the Beachmont Eye Institute/Eyes R Us.
Send questions to: Beachmont@gmail.com
Tel: 784 456-1210

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