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A common type of refractive factor.
The eye does not focus light evenly onto the retina.
The eye fails to focus the light equally on the retina leading to blurred or distorted vision.
It can be congenital or can develop gradually in life.
It occurs when light is bent differently depending on where it strikes the cornea and passes through the eyeball.
It is called corneal astigmatism.
The cornea of a normal eye is curved like a basketball.
The eye with astigmatism has a cornea that is curved more like a football, and can cause images to appear blurry and stretched out.
Usually causes vision to be blurred or distorted to some degree at all distances.
Can affect both children and adults.
Signs and symptoms of astigmatism include:
Headaches
Eyestrain
Squinting
Distorted or blurred vision at all distances
Difficulty driving at night
It is usually discovered during a comprehensive dilated eye exam.
It can be corrected with eyeglasses, contact lenses, or surgery.
It usually occurs with myopia (nearsightedness) or hyperopia (farsightedness)
It is a refractive error.
It is not an eye disease or eye health issue.
Astigmatism in some cases is caused by the distortion of shape of the lens, and is referred to as lenticular astigmatism.
There are three primary types of astigmatism:
Myopic astigmatism.
Hyperopic astigmatism.
Mixed astigmatism.
Astigmatism is also classified as regular or irregular.
In regular astigmatism, the principal meridians are 90 degrees apart, perpendicular to each other.
In irregular astigmatism, the principal meridians are not perpendicular.
Most astigmatism is the result of regular corneal astigmatism, which gives the front surface of the eye an oval shape.
Irregular astigmatism can result from: an eye injury that has caused scarring on the cornea, from certain types of eye surgery or from keratoconus, a disease that causes a gradual thinning of the cornea.
It is detected during a routine eye exam.
Retinoscopy estimates the amount of astigmatismsm
Astigmatism can usually be corrected with eyeglasses, contact lenses or refractive surgery.
Refractive surgery is one of the less common astigmatism correction options.
Eyeglasses are the simplest and safest correction for astigmatism.
Contact lenses work by becoming the first refractive surface for light rays entering the eye, causing a more precise refraction or focus.
Refractive surgery changes the shape of the cornea restoring the focusing power of the eye by allowing the light rays to focus precisely on the retina for improved vision.
There are multiple types of refractive surgeries.