Wednesday, April 17, 2024

How Does Astigmatism Affect Vision

How To Correct Astigmatism

Astigmatism Explained

All degrees of astigmatism can be corrected. The treatment used to correct your astigmatism will depend on the degree of your astigmatism. Eyeglasses can be used to improve vision by providing additional power in specific parts of the lens. Contact lenses are also used to provide clear vision and a wider field of view for our patients. While standard soft lenses may not be effective in astigmatism correction, special toric soft contact lenses can be used. They have a better bending power, which improves refraction. Refractive surgery can also be used to change the corneas shape with laser eye surgery. These refractive surgeries require healthy eyes that are free of corneal scars, retinal problems, and other eye diseases.

What Tests Might I Need

Various tests measure how your eyes focus light and what type of lenses you need to improve your vision. Astigmatism tests include:

  • Visual acuity: You read letters on a distance chart and receive a measurement . Alternative methods are used for young children and non-verbal patients.
  • Keratometry/topography: This instrument measures the curve of your cornea. Your provider focuses light on the cornea and measures its reflection. This number is important for getting contact lenses that fit correctly and diagnosing regular versus disease-induced astigmatism.
  • Refraction: Your provider measures how light focuses within your eye to create a clear or blurry image. This can be done with or without your input, so it can still be done in children and non-verbal adults.

Why Do I See Starbursts Around Lights At Night

Starbursts, or a series of concentric rays or fine filaments radiating from bright lights, may be caused by refractive defects in the eye. Starbursts around light are especially visible at night, and may be caused by eye conditions such as cataract or corneal swelling, or may be a complication of eye surgery.

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Your Blurry Vision Could Be Caused By Astigmatism

Your Blurry Vision Could Be Caused by Astigmatism

Does everything look blurry, whether you’re reading a book or watching the sun set in the distance? Your blurry vision could be caused by astigmatism, a refractive error that affects 1 in 3 people, according to the American Academy of Ophthalmology.

When Everything Is Blurry

Myopia makes distant objects look fuzzy, while hyperopia affects your ability to see close objects clearly. Astigmatism, another type of refractive error, causes blurry vision at both near and far distances. Refractive errors happen when light rays entering the eye aren’t properly bent and focused on the retina, the light-sensing cells that line the back of the eye.

Astigmatism can occur on its own or can happen in combination with myopia or hyperopia.

Astigmatism Symptoms and Causes

Blurry vision isn’t the only symptom of astigmatism. The refractive error may also cause headaches and eyestrain, particularly after reading or spending time using your laptop or tablet.

Astigmatism may also make it difficult to see well at night or in dimly lit rooms and can cause halos around lights.

Astigmatism can be occur due to an issue with:

Although astigmatism often occurs for unknown reasons, you may be more likely to develop it if you had eye surgery, an eye injury or keratoconus, according to the American Optometric Association. Keratoconus is a condition that causes the cornea to become thinner and cone shaped.

What You Can Do to Improve Your Vision

Your Lens Or Cornea Is More Like A Football Than A Basketball


For perfect vision, the front of your cornea is supposed to have a spherical shape, like a basketball. If you have astigmatism, one or both of those important, anatomical parts is oblong in shape, more like a football.

Thus, when light enters the pupil, it refracts along the interior surface of the eye and comes to two focal points instead of the optimal, single focal point. The more oblong the shape, the further apart those points are, and the blurrier your vision will be.

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How Is Visual Acuity Measured

Having 20/20 vision means perfect vision. The top number is the standardized testing distance used, which is 20 feet. The bottom number represents the smallest letter size you can read. So if you have 20/40 vision, it means you need to be within 20 feet to read a letter that someone with perfect vision could see clearly at 40 feet.

How Is Astigmatism Diagnosed

An optometrist can diagnose astigmatism during a regular eye exam.

A typical eye exam includes:

A visual acuity test to check the ability to discern shapes and details.

A refraction to determine your refractive error . The eye doctor bases your eyeglass prescription on the results of this test.

A visual field test to check the peripheral vision.

An eye muscle function test to check for issues with the muscles around the eyeballs.

A pupil response test to check how your pupils respond to light and viewing objects at near.

A tonometry test to measure eye pressure.

Dilation to check for problems with the inner parts of the eyes.

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How Does The Eye Doctor Diagnose Astigmatism

Your Classic Vision Care optometrist performs a comprehensive eye exam to diagnose astigmatism. Testing to diagnose astigmatism may include:

  • Corneal topography, a map of your cornea
  • Keratometry, a corneal curvature measurement
  • Retinoscopy, a check of light reflection off your retina

During your exam, your optometrist also determines your eyeglasses or contact lens prescription, if you need one.

Overview: What Is Astigmatism

ASTIGMATISM vision vs NORMAL vision

Astigmatism refers to a common eye condition that causes your vision to be blurry at all distancesboth near and farbecause the curvature of your cornea or natural lens is irregularly shaped. This refractive error occurs because your eye cannot focus light properly, directly onto your retina, the light-sensitive surface that lines the back of your eye.

If your cornea is shaped more like a football than a soccer ball, your eye wont be able to focus light rays at a single point. If the eyes lens curvature changes, this can worsen your astigmatism. This can happen in adulthood and with naturally occurring cataracts.

There are three different types of refractive errors, including astigmatism:

  • Myopia This occurs when your eye focuses light in front of the retina, so you have trouble seeing objects that are far away.
  • Hyperopia This occurs when your eye focuses light behind the retina, so you have trouble seeing objects that are nearby.
  • Astigmatism This occurs when your eye focuses light at different points both in front of and behind the retina, so you have trouble seeing objects both far away and close up.

You can inherit corneal errors like astigmatism through your genetics or develop it after an eye injury, eye surgery, or eye disease like keratoconus, which causes your cornea to form into a conical shape.

Keratoconus is an eye disease that causes irregular and often high amounts of astigmatism.

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Facts You Didnt Know About Astigmatism

If youre a glasses or contact lens wearer, this question might have come up before: Do you have astigmatism? If youre not quite sure how you should answer, then this blog post is for you. Were going to share some of the more common facts about astigmatism, as well as tell you what symptoms you can and should look out for, and the steps you can take to treat them.

Extreme Astigmatism: > 300 Diopter

Extreme astigmatism will require treatment so that you can see objects both near and far with ease. If you do not treat extreme astigmatism, you will not be able to see clearly at all.


There are five types of astigmatism: simple myopic, simple hyperopic, compound myopic, compound hyperopic, and mixed. They are categorized into different levels of severity: mild, moderate, severe, and extreme.

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Focus Of The Principal Meridian

With accommodation relaxed:

  • Simple astigmatism
  • Simple hyperopic astigmatism â first focal line is on the retina, while the second is located behind the retina.
  • Simple myopic astigmatism â first focal line is in front of the retina, while the second is on the retina.
  • Compound astigmatism
  • Compound hyperopic astigmatism â both focal lines are located behind the retina.
  • Compound myopic astigmatism â both focal lines are located in front of the retina.
  • Mixed astigmatism â focal lines are on both sides of the retina .
  • How Astigmatism Affects Light Perception

    Impaired Vision with Astigmatism. As Astigmatism Stock Vector ...

    Ophthalmologists say blurry vision from astigmatism is the same no matter what time of day it is. However, blurry vision can become especially noticeable at night because of the contrast between light and dark.

    “People will say, ‘I have trouble driving at night, but not in the day.’ And it’s not that in the daytime, they don’t have the refractive error, it’s just that they’re able to overcome it a lot easier than at night when there’s less light,” says Anna Park, an ophthalmologist in the Martin P. Kolsky Group Chartered in Washington, DC, and an attending physician at the Washington Hospital Center.

    The reason vision may not be as blurry during the day is because there’s less light for your eye to focus. To compensate, the pupil dilates to let in more light. A larger pupil means more of the cornea and lens are being used to focus the light. Using more of these surfaces increases the symptoms of astigmatism or other refractive errors.

    “Night vision is the same as day vision, it’s just that the light rays aren’t focused on your retina as they should be, so the picture you get is blurred and distorted. In general, in lower light, refractive errors come out more often,” says Park.

    Most astigmatisms are mild, Chan says. “So people may not notice the problem during the day. But at night, lights headlights, stop signs will seem to come at you.”

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    Treating Astigmatism At Dmei

    If you are experiencing blurry or distorted vision, schedule a comprehensive eye exam so one of our eye doctors can test you for astigmatism. DMEI offers several treatment options for astigmatism, including contact lenses, glasses, and laser surgery.

    To schedule an eye appointment, call us at 405.271.6060 or 800.787.9012, or fill out our appointment request form using the button below.

    If you are interested in LASIK, learn more by clicking on the button below or calling 405.271.2500 to schedule your free screening.

    The Cause Of Astigmatism Is Unclear

    While we know the answer as to why a persons eyesight is blurry and what affect this can have on vision, many optometrists and researchers still arent sure as to how this happens in the first place. What we do know is people who have astigmatism are typically born with this this condition, meaning their eye resembles a football to begin with. Though much less likely, trauma or injury to the eye may force this shape to shift too. One way you cant get astigmatism, though, is by sitting too close to the television. While this was once believed to be a sure-fire way to develop the condition, consider that myth debunked.

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    You May Be A Candidate For Lasik Surgery

    Astigmatism patients are some of our best LASIK surgery candidates because our cool lasers are ideal for perfectly shaving away that extra curve and restoring a more perfect, spherical shape to your cornea or lens. As with contacts, we may not recommend LASIK if your astigmatism is very mild and we feel its wise to wait a while waiting for the condition to progress a bit before proceeding with surgery.

    Astigmatism Combined With Refractive Errors

    Astigmatism Vs Normal Vision In VR (Meta Quest 2)

    You can also have astigmatism combined with other refractive errors. Each of the five types is defined by the location of where the cornea focuses light on the retina, also known as the focal point.

    In a normal eye, the meridians focus light at a single point on the retina. When you have astigmatism, the eye cannot focus light on a single point and instead creates two focal points.

    For reference, myopic is another term for nearsightedness when objects farther away are blurry and hyperopic is another term of farsightedness when objects close to you are blurry.

    • Simple Myopic: This is a combination of astigmatism and nearsightedness in which one focal point comes before the retina, while the other is on the retina.
    • Compound Myopic: This is a combination of astigmatism and nearsightedness in which both focal points come before the retina.
    • Mixed: This is a combination of astigmatism and both nearsightedness and farsightedness in which one focal point is before the retina and the other focal point is behind the retina.
    • Simple Hyperopic: This is a combination of astigmatism and farsightedness in which one focal point is on the retina while the other is behind the retina.
    • Compound Hyperopic: This is a combination of astigmatism and farsightedness in which both focal points are behind the retina.

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    What Are The Different Levels Of Severity

    The severity of astigmatism is stated in diopters.

    A diopter is a unit of measurement of the optical power of a lens. Essentially, diopter strength references the power of a lens. A high diopter number means your vision is worse, or requires more correction.

    The severity of an astigmatism is correlated to the diopter number.

    • Mild astigmatism: less than 1.00 diopters
    • Moderate astigmatism: 1.00 to 2.00 diopters
    • Severe astigmatism: 2.00 to 3.00 diopters
    • Moderate astigmatism: more than 3.00 diopters

    To determine if someone has astigmatism, the doctor typically performs a comprehensive dilated eye examination. They will also ask about any vision changes. This can help the doctor to determine if the symptoms are associated with astigmatism.

    How To Treat Astigmatism

    If you have a history of vision problems, it may be time to consult a professional.

    “When we prescribe glasses or contacts, what we’re doing is providing a prescription that’ll help focus the light coming into the eye and to the retina so that the picture is clear,” says Park.

    Chan agrees. “Any time you have blurred vision, you should see a doctor because a lot of things have similar symptoms,” she says. Here are a few common ways astigmatism is treated:

    • Glasses: Prescription glasses refocus the images and lights to correct astigmatism, says Chan. Tinted glasses reduce some glare but won’t help with astigmatism.
    • Contact lenses: If it’s strong enough to require contacts, toric lenses have two light-bending powers that cross perpendicularly to treat astigmatism.
    • Laser surgery: Lasik laser surgery can be used to correct astigmatism. If a patient has corneas deemed too thin for Lasik, photorefractive keratectomy is an option.

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    Headaches And Eye Strain

    People with very mild astigmatism might not ever notice any blurry vision, but that may be because the eye muscles that help with focus are working overtime. The result is eyes that feel tired, sore or strained, and eye strain can sometimes lead to headaches. Eye strain from uncorrected astigmatism can feel very similar to digital eye strain.

    Difficulty Seeing At Night

    Eye Conditions, Diseases and Disorders

    The symptoms of astigmatism can worsen when its dark. In low light, your pupils dilate to let more light into your eye and help you see better. But when you have astigmatism, this makes blurry vision worse.

    Your eye lets more peripheral light in, which can make lights look fuzzy and create a halo effect. Halos and glare from light can make it difficult to focus on tasks in the dark, such as driving at night.

    Astigmatism is generally diagnosed in routine eye exams. It can occur alongside nearsightedness and farsightedness, and it ranges in severity.

    If you have an astigmatism, your Pacitic Eye eye doctor will determine the extent of the condition and recommend treatment options to improve your vision. Astigmatism can generally be corrected with eyeglasses, contact lenses, or refractive surgery.

    Astigmatism correction helps your eyes focus clearly. With the right glasses or contacts prescription, you can enjoy sharper vision and less eyestrain.

    Do you suspect astigmatism? Is it time for your next eye exam? Schedule your appointment online or call Pacific Eye, which has seven locations in San Luis Obispo and Santa Barbara counties. You can also request an appointment here on the website.

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    Distorted Or Double Vision

    Distorted or wavy vision is another problem that may be caused by astigmatism. The asymmetry in the shape of the cornea or lens can refract light in such a way that objects seem bent or warped, like how things look in a fun-house mirror.

    High degrees of astigmatism can also cause double vision, or seeing two images of one object. Objects may also look larger or smaller than they really are.

    Will Glasses Help With The Effects Of Astigmatism At Night

    Yes, prescription glasses will help with astigmatism symptoms that affect your night vision. If you see halos, starburst patterns, or blurriness around lights at night, then wearing glasses should eliminate or dramatically reduce these distortions.

    Not only will wearing glasses for astigmatism at night help your eyesight, but itll make you a safer driver. Treating your astigmatism means youre less likely to be distracted or misled by blurry lights while driving after dark.

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    Learn More On What Causes Astigmatism And How To Correct It

    At Nevada Eye Physicians, we perform comprehensive eye exams that detect errors, such as astigmatism. After a series of visual testing, we can determine if you have astigmatism and what treatment can be used to correct it. To schedule an appointment today for an eye exam, contact one of our seven locations including Las Vegas, Henderson, Boulder City, Mesquite, and Pahrump, NV.

    Blurred Vision Near Or Far Could Be Astigmatism

    Astigmatism: A Demo of How it Affects Vision

    11/23/2020 | Education

    Has life seemed a little blurry lately? It may be you are finally noticing signs of vision loss due to a refractive error called astigmatism. The only way to tell for sure is by scheduling a visit to your optometrists office.

    One of the most common vision conditions, astigmatism of one or both eyes affects close to 30% of the population, so youre not alone. The leading cause of astigmatism is genetics. If you are diagnosed with astigmatism, odds are your father and/or mother had it, too. So in most cases, there is nothing you can do to prevent its onset. Fortunately, correcting the condition is 100% within your control and immediate assessment and treatment are recommended.

    Letting astigmatism go uncorrected for too long without corrective lenses or LASIK treatment can have a negative effect on school, work, and driving which leads to safety issues, especially when driving at night.

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