Astigmatism is a condition that affects the eyes. It causes distance vision to blur. It is often seen at birth and requires corrective lenses or surgery as a part of the treatment.
What is Astigmatism?
It is a vision problem that causes blurring due to the irregular shape of the cornea. Normally the cornea is clear, round, dome-shaped that covers the iris and pupil. The cornea and lens are both smooth and curve in all directions equally. This is very important as it helps focusing rays sharply towards the retina present at the back of the eye. This helps you see the images clearly. But, if the cornea is curved irregularly or isn’t smooth enough, it causes images to blur. This may lead to shortsightedness, farsightedness or both.
What Causes Astigmatism?
Astigmatism is the result of irregular curvature of the cornea or lens. This causes improper refraction of light rays, called as refractive errors. It can lead to blurred vision or distorted vision. Most people are born with astigmatism. The exact cause of the irregular shape of the cornea or lens is unknown. It is thought to be an inherited condition. In some cases, eye trauma, eye surgery or eye diseases can lead to astigmatism. In children, it may result due to sitting in front of the television too close for too long. Reading under low lights can also astigmatism.
Symptoms of astigmatism are as follows:
If problems with vision affect your daily tasks, it is better to visit a doctor for an eye check up.
The doctor will conduct a comprehensive eye test. This will help the doctor understand how the eyes focus light. It will also allow him to understand the power of the optical lenses needed to correct the vision. The tests include:
- Visual acuity: You will be asked to read letters on a distance chart. It will help determine the smallest size one is able to read from a distance of 20 feet.
- Keratometry: In this test, a keratometer is used to measure the curvature of the cornea. This helps in determining the proper size of the contact lenses required.
- Refraction: Here, a phoropter is used to see how the eyes focus light. There is a series of lenses and measures on the instrument that helps determine the lens power that will impart clear vision to the eye.
The treatment for astigmatism is to correct the uneven curvature that causes the vision to blur. The methods of treatment include:
- Eyeglasses: The person is prescribed with eyeglasses that helps them correct the problem of nearsightedness or farsightedness.
- Contact lenses: The use of contact lenses helps in correcting vision problem for people with higher amounts of astigmatism.
- Refractive surgery: Surgery is the treatment option when it can help in changing the shape of the cornea. Surgical methods include laser surgery (LASIK surgery), photorefractive keratectomy (PRK) and laser-assisted subepithelialkeratomileusis (LASEK) surgery.
Astigmatism can change with time. Thus, it is absolutely necessary to keep undergoing eye check ups half-yearly. This will help one understand if there is any need for new glasses or contact lenses.
Call your eye doctor today for an appointment, if you find yourself squinting when trying to focus on an object, suffer from frequent headaches and eye discomfort.
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Date last updated: March 12, 2015