A common type of refractive error, astigmatism affects vision quality, and its severity can range from mild to severe. In identifying the extent of astigmatism, the severity scale is used.
Astigmatism Severity Scale
Depending on how much astigmatism you have, your vision will be affected. Look at the cylinder (CYL) number on your glasses prescription to determine how much astigmatism you have.
According to the severity scale, astigmatism can range from mild (1.00 diopters or less) to extremely severe (3.00 diopters or more).
Mild Astigmatism: < 1.00 diopter
A mild degree of astigmatism is considered normal. Most people with mild astigmatism do not require corrective lenses or eye surgery to see clearly. You may not be aware of any symptoms, however.
Moderate Astigmatism: 1.00 to 2.00 diopters
Those with moderate astigmatism require corrective lenses or laser eye surgery for clear vision.
In spite of the fact that you may not require glasses or contact lenses, you will probably be able to notice the effects of moderate astigmatism. Glasses and contact lenses can be used to improve vision problems caused by moderate astigmatism.
Severe Astigmatism: 2.00 to 3.00 diopter
There are serious symptoms associated with severe astigmatism, such as blurred vision that affects daily functioning and headaches that can have a negative impact on your health.
Extreme Astigmatism: > 3.00 diopter
It is necessary to treat extreme astigmatism in order to be able to see objects clearly close-up and at a distance. If you do not treat extreme astigmatism, you will not be able to see anything at all clearly.
An irregularly shaped cornea (the front surface of the eye) or a naturally occurring lens can result in astigmatism.
Light is bent evenly and properly focuses on the retina, the light-sensitive surface at the back of the eye, when the lens and cornea are smoothly curved.
Those suffering from astigmatism have corneas or lenses that are shaped more like a football rather than a soccer ball, which interferes with the eyes’ ability to focus light properly.
When your eye’s cornea is more like a football than a soccer ball, light rays cannot be focused at a single point. Astigmatism can be worsened by changes in the curvature of the eye’s lens.
How Does Astigmatism Affect Visual Impairment?
There may be no symptoms or visual impairments associated with mild astigmatism.
An astigmatism patient may experience the following symptoms:
Trouble seeing objects both close up and far away
Difficulty with night vision
Seeing glares and halos at night
Seeing shadowy images
Does Astigmatism Worsen with Age?
Age-related changes in the muscles of your eyelids contribute to the development of astigmatism. These muscles help maintain the shape of your cornea.
Is 1.0 Astigmatism Bad?
It is considered mild when the measurement of astigmatism exceeds 1.0. It may or may not cause any symptoms.
Astigmatism, however, is not the same for everyone. Astigmatism can be of varying degrees of severity.
What Do Astigmatism Numbers Mean?
Your eye doctor will measure your astigmatism in diopters.
For context, a perfectly round eye with no astigmatism has 0 diopters. Most people have between 0.5 and 0.75 diopters of astigmatism.5
People1.5 or more diopters of astigmatism usually need prescription glasses or contact lenses to see clearly.
Where to Find Astigmatism Measurements on a Glasses Prescription
Each prescription for eyeglasses contains three numbers, and the last two (CYL and Axis) indicate astigmatism:
Spherical (sphere). Indicates whether you are nearsighted (a minus sign) or farsighted (a plus sign). The higher the number, the stronger the lens
Cylinder (CYL). Measuresdiopters.
Axis.degrees from 0 to 180.
What Level of Astigmatism Requires Glasses?
If you are suffering from moderate astigmatism (1.00 to 2.00 diopters), wearing glasses or other astigmatism treatment may be necessary.
A doctor may prescribe glasses to a patient with a 0.75 diopter because many people still notice improvements in their vision with glasses.
Astigmatism can change over time, so you should schedule regular eye examinations with your eye doctor. If you are wearing glasses, you should make sure your prescription stays the same.
Types of Refractive Errors
The type of refractive error that is associated with astigmatism is among four types. They include:
People who have myopia have trouble seeing objects that are far away because their eyes focus light in front of their retinas.
Objects nearby are blurry when you have hyperopia, which occurs when your eye focuses light behind the retina.
Age-related farsightedness or presbyopia is a condition that causes many people who had never needed glasses to wear them in order to read or see objects up close as they age.
In astigmatism, light is focused at different points in front of and behind the retina of the eye. Astigmatism can cause blurry vision for both close-up and far-away objects.
There are five types of astigmatism. Here are some things you should know about each type:
Simple myopic astigmatism. When the light hits two focal points: one before the eye’s retina and one on the eye’s retina.
Simple hyperopic aatigmatism. Happenstwo focal points: one directly on the eye’s retina and one behind the eye’s retina.
Compound myopic astigmatism. Happenshits two focal points at two different locations in front of the eye’s retina.
Compound hyperopic astigmatism. When the lightto two different virtual locations behind the eye’s retina.
Mixed astigmatism. Happens when light rays hit two focal points: one before the eye’s retina and one behind the eye’s retina.
How Is Astigmatism Diagnosed?
During a comprehensive eye exam, an optometrist can diagnose astigmatism by measuring how your eye focuses light and determining how much lens power is required to correct it.
An eye exam may include the following components:
Eye chart. Reading letters on an eye chart tests your visual acuity (vision sharpness) at different distances.
Phoropter. This is a large device that looks like binoculars. It contains many lenses of various powers. Your doctor will ask which lenses providevision.
Autorefractor. This device measures your astigmatism or other refractive error by shining a light into your eye.
Keratometer or corneal topography. This
Can LASIK Correct Astigmatism?
There is a possibility of LASIK-type laser surgery (laser in situ keratomileusis) and PRK-type laser surgery (photorefractive keratectomy) being able to correct mild to moderate astigmatism. Both types of laser surgery permanently change the shape of the cornea, so that you will no longer have to wear eyewear to see clearly.
A LASIK procedure uses an excimer laser to remove tissue from the cornea’s inner layer, while PRK removes tissue from both the superficial and inner layers of the cornea.
What Happens During LASIK?
To perform LASIK surgery, the surgeon uses a femtosecond laser or a mechanical microkeratome to cut a flap in your cornea. At one end of the flap is a hinge; this is where the surgeon folds back the flap to reveal the stroma (middle section of the cornea).
Following that, they will use pulses from a computer-controlled laser to remove part of the corneal flap and vaporize part of the stroma.
According to the latest research, LASIK takes approximately 10 minutes per eye – and the laser itself takes approximately 20 to 50 seconds to correct your vision.
Different types of astigmatism vary in severity. Astigmatism is a vision condition caused by an irregularly shaped cornea or lens. It can be inherited, develop in childhood, or become worse as one ages.
There are three levels of astigmatism severity: mild, moderate, and severe. Mild astigmatism requires no correction, but severe or moderate astigmatism may require contact lenses, eyeglasses, or eye surgery such as LASIK.