what is astimatism ? what cause astimatism ? how is astimatism corrected ?
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Answer:
Astigmatism is a common vision problem caused by an error in the shape of the cornea. With astigmatism, the lens of the eye or the cornea, which is the front surface of the eye, has an irregular curve. This can change the way light passes, or refracts, to your retina.
It’s not known what causes astigmatism, but genetics is a big factor. It’s often present at birth, but it may develop later in life. It may also occur as a result of an injury to the eye or after eye surgery. Astigmatism often occurs with nearsightedness or farsightedness.
The symptoms of astigmatism may differ in each person. Some people don’t have any symptoms at all. The symptoms of astigmatism include:
blurry, distorted, or fuzzy vision at all distances (up close and far away)
difficulty seeing at night
eyestrain
squinting
eye irritation
What is astigmatism?
Astigmatism is a common vision problem caused by an error in the shape of the cornea. With astigmatism, the lens of the eye or the cornea, which is the front surface of the eye, has an irregular curve. This can change the way light passes, or refracts, to your retina. This causes blurry, fuzzy, or distorted vision. Farsightedness and nearsightedness are two other types of problems with the way light passes to your retina. Farsightedness is called hyperopia. Nearsightedness is called myopia.
What are the types of astigmatism?
The two main types of astigmatism are corneal and lenticular. A corneal astigmatism happens when your cornea is misshapen. A lenticular astigmatism happens when your lens is misshapen.
What causes astigmatism?
It’s not known what causes astigmatism, but genetics is a big factor. It’s often present at birth, but it may develop later in life. It may also occur as a result of an injury to the eye or after eye surgery. Astigmatism often occurs with nearsightedness or farsightedness.
Who is at risk for astigmatism?
Astigmatism can occur in children and adults. Your risk of developing astigmatism may be higher if you have any of the following:
a family history of astigmatism or other eye disorders, such as keratoconus (degeneration of the cornea)
scarring or thinning of your cornea
excessive nearsightedness, which creates blurry vision at a distance
excessive farsightedness, which creates blurry close-up vision
a history of certain types of eye surgery, such as cataract surgery (surgical removal of a clouded lens)
What are the symptoms of astigmatism?
The symptoms of astigmatism may differ in each person. Some people don’t have any symptoms at all. The symptoms of astigmatism include:
blurry, distorted, or fuzzy vision at all distances (up close and far away)
difficulty seeing at night
eyestrain
squinting
eye irritation
headaches
See a doctor if you have symptoms of astigmatism. Some symptoms may also be due to other health or vision problems.
How is astigmatism diagnosed?
An optometrist or ophthalmologist diagnoses astigmatism through a comprehensive eye examination. An optometrist is a doctor who diagnoses vision problems and eye diseases. An ophthalmologist is a doctor who provides medical and surgical treatment of vision problems and eye diseases. There are several tests optometrists and ophthalmologists may use during your eye examination to diagnose astigmatism.
Visual acuity assessment test
During a visual acuity assessment test, your doctor will ask you to read letters from a chart at a specific distance to determine how well you can see the letters.
Refraction test
A refraction test uses a machine called an optical refractor. The machine has multiple corrective glass lenses of different strengths. Your doctor will ask you to read a chart while looking through lenses that are different strengths on the optical refractor. They’ll eventually find a lens that appropriately corrects your vision.
Keratometry
Keratometry is a way for your doctor to measure the curvature of your cornea. They will do this by looking at your eye through a keratometer.
What are the treatments for astigmatism?
Mild cases of astigmatism may not require treatment. Your doctor may treat astigmatism that causes vision problems by using one of the following methods.
Corrective lenses
Corrective eyeglasses and contact lenses prescribed by a doctor are the most common and least invasive treatments for astigmatism.
Orthokeratology (Ortho-K)
Orthokeratology (Ortho-K) is a treatment that uses rigid contact lenses to temporarily correct the irregular curvature of your cornea. You’ll wear rigid contact lenses for limited periods of time.
Surgery
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