- Risk Factors
- Tests and Diagnosis
- Treatment and Drugs
- Find a Doctor or Location
- How Your Astigmatism Can Be Corrected
- Astigmatism | Causes and Treatment
- What Exactly Is Astigmatism?
- Astigmatism symptoms
- What causes astigmatism?
- 3 types of astigmatism
- Astigmatism tests
- Astigmatism correction options
- Astigmatism: Here’s What You Need To Know
- What It Means To Have Astigmatism
- Astigmatism Can Be Treated With Corrective Lenses
- Talk To Us About Your Vision
- The content on this blog is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of qualified health providers with questions you may have regarding medical conditions
- Astigmatism | Mooresville Optometrist
- How Corneal Defects Cause Astigmatism
- Diagnosis and Solutions at Our Optometry Clinic
- Our Mooresville Clinic Holds the Answers to Your Astigmatism
- How Do You See the World if You Have Astigmatism?
- How Does Astigmatism Affect the Eyes?
- How Does Astigmatism Impact Vision?
- What Are the Different Levels of Severity?
- Astigmatism Treatment Options
- Easily Corrected
- What Is Astigmatism?
Astigmatism is a condition in which your eye isn’t completely round. Almost all of us have it to some degree.
Ideally, an eyeball is shaped a perfectly round ball. Light comes into it and bends evenly, which gives you a clear view. But if your eye is shaped more a football, light gets bent more in one direction than another. That means only part of an object is in focus. Things at a distance may look blurry and wavy.
It’s common to have astigmatism along with nearsightedness (myopia) or farsightedness (hyperopia). These three conditions are called refractive errors because they involve how your eyes bend (refract) light.
Astigmatism is fairly easy for an eye doctor to fix with glasses, contacts, or surgery.
Symptoms of astigmatism may include:
- Blurry or distorted vision
- Trouble seeing at night
Most people are born with it, but experts don’t know why. You can also get it after an eye injury, an eye disease, or surgery.
Rarely, a condition called keratoconus can cause astigmatism by making the clear front part of your eye (your cornea) thinner and more cone-shaped. You’ll probably need contacts (but not glasses) to see clearly.
You can’t get astigmatism from reading in low light or sitting too close to the TV.
Astigmatism symptoms come on slowly. Go to an eye doctor if you notice changes in your vision. You’ll need a complete eye exam. Your doctor will test the sharpness of your eyesight by asking you to read an eye chart. They’ll also use tools to measure your vision, including:
- Phoropter. You look through a series of lenses to find the ones that give you the clearest vision.
- Keratometer/topographer. This machine uses a circle of light to measure the curve of your cornea.
- Autorefractor. This device shines light into your eye and measures how it changes as it bounces off the back. This gives your doctor an idea of which lenses you need.
Your prescription will have some letters and numbers. OD means oculus dexter, your right eye, and OS is oculus sinister, your left eye. OU means oculus uterque, or both eyes.
The numbers are measurements called diopters.
- The first number is for something called spherical correction. If it has a minus sign, you’re nearsighted. If there’s a plus sign, you’re farsighted. A higher number means blurrier vision.
- The second numbers are your cylindrical correction. This is how strong your astigmatism is.
- The third one is the axis, the location of the astigmatism on your cornea.
For example, a prescription of “OD -1.00 x -2.00 x 155” means your right eye has 1 diopter of nearsightedness and 2 diopters of astigmatism at 155 degrees on your cornea.
Glasses or contacts can correct almost all cases of astigmatism. But if you have only a slight astigmatism and no other vision problems, you may not need them.
There are two treatments for the common levels of astigmatism:
- Corrective lenses. That means glasses or contacts. If you have astigmatism, your doctor will probably prescribe a special type of soft contact lenses called toric lenses. They can bend light more in one direction than the other. If your case is more severe, you might get gas-permeable rigid contact lenses for a procedure called orthokeratology. You wear the lenses while you sleep, and they reshape your cornea. You’ll need to keep wearing the lenses to hold this new shape, but you won’t have to wear them as often.
- Refractive surgery. Laser surgery also changes the shape of your cornea. Types of refractive surgery include LASIK and PRK. You’ll need to have otherwise healthy eyes with no retina problems or corneal scars.
Irregular astigmatism is far less common and is linked to problems with your cornea, the front part of the eye. Keratoconus is one example.
Many infants are born with astigmatism, and it often goes away before their first birthday.
Because children usually can’t tell that there’s a problem with their vision, they need regular eye exams starting about 6 months of age. A child with an untreated vision condition might have a hard time at school, and this could lead to an incorrect learning disorder diagnosis.
Yanoff, M. Ophthalmology, Mosby, 2008.
MedlinePlus: “Vision Problems.”
National Eye Institute: “Facts About Refractive Errors,” “Astigmatism.”
American Academy of Ophthalmology: “What Causes Astigmatism?” “Astigmatism Diagnosis and Treatment,” “What Do Astigmatism Measurements Mean?”
American Optometric Association: “Astigmatism.”
Mayo Clinic: “Astigmatism.”
Canadian Association of Optometrists: “How to Read Your Eyeglass Prescription.”
Boston Children’s Hospital: “Astigmatism.”
© 2019 WebMD, LLC. All rights reserved. Symptoms
- Distortion or blurring of images at all distances
- Headache and fatigue
- Squinting and eye discomfort or irritation
The symptoms described above may not necessarily mean that you have astigmatism. However, if you experience one or more of these symptoms, contact your ophthalmologist for a complete exam.
Normally, the cornea is smooth and equally curved in all directions and light entering the cornea is focused equally on all planes or in all directions.
In astigmatism, the front surface of the cornea is curved more in one direction than in the other. This abnormality may result in vision that is much looking into a distorted, wavy mirror.
The distortion results because of an inability of the eye to focus light rays to a single point.
If the corneal surface has a high degree of variation in its curvature, light refraction may be impaired to the degree that corrective lenses are needed to help focus light rays better. At any time, only a small proportion of the rays are focused and the remainder are not, so that the image formed is always blurred. Usually, astigmatism causes blurred vision at all distances.
A small amount of astigmatism is very common and the tendency to develop astigmatism is inherited. A larger amount of astigmatism can be associated with diseases such as keratoconus.
Tests and Diagnosis
The amount of astigmatism in the eye can be measured in various ways. The autorefraction or the subjective refraction— the patient’s response—that are done at the beginning of an eye exam is one way to measure astigmatism. The amount of astigmatism caused by the cornea is measured in the clinic by a diagnostic instrument called a keratometer.
Treatment and Drugs
If the degree of astigmatism is slight and there are no other problems of refraction, such as nearsightedness or farsightedness, corrective lenses may not be needed. If the degree of astigmatism is great enough to cause eye strain, headache, or distortion of vision, corrective lenses will be needed for clear and comfortable vision.
The corrective lenses needed for astigmatism are called toric lenses and they have an additional power element called a cylinder. They have greater light-bending power in one axis than in others. Your ophthalmologist will perform precise tests during your exam to determine the ideal lens prescription. Refractive surgery also may be an option for correcting some forms of astigmatism.
Astigmatism may increase slowly. Regular eye care can help to insure that proper vision is maintained. You may have to adjust to wearing eyeglasses or contact lenses if you do not wear them now. Other than that, astigmatism probably will not significantly affect your lifestyle.
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Reviewed by Jill E. Bixler, M.D.
How Your Astigmatism Can Be Corrected
Astigmatism usually causes vision to be blurry at distance as well as near. Patients with astigmatism often feel tired after reading and find that letters and words appear to be slanted. Squinting and tilting the head seems to improve vision distortion caused by astigmatism.
Astigmatism is caused by the cornea having an oblong shape, a football, instead of a spherical shape, a basketball.
A cornea with astigmatism has two curves, one flat curve and one that is steep. Light is then focused at two points instead of one. One point of focus may be in front of the retina and the other behind.
This causes images to appear distorted in addition to appearing blurry. Astigmatism may also be caused by an irregularly shaped crystalline lens. This condition is termed “lenticular astigmatism.”
Astigmatism is diagnosed by a manual keratometer, an instrument used to measure the curvature of the cornea. A keratometer is often used in a basic eye examination.
The diagnosis also may be made by using a corneal topographer. A corneal topographer is an instrument that gives a color-coded map, similar to a topographical map of mountains. Steeper areas are indicated in red and flatter areas in blue.
A wavefront aberrometer will also give the eye doctor much more precise information about astigmatism.
Astigmatism may be corrected with glasses, contact lenses or surgery.
- Glasses: Glasses work well with patients with astigmatism. Patients with high amounts of astigmatism must have their glasses carefully adjusted to their faces.
- Contact lenses: Contact lenses that correct astigmatism are called toric contact lenses. Patients with large amounts of astigmatism have greater success with rigid gas permeable contact lenses.
- Surgery: Surgical vision correction procedures and an incision procedure, known as astigmatic keratotomy, can also successfully correct astigmatism.
If you have astigmatism, don't think you can't have LASIK eye surgery. It is a possibility for most.
LASIK surgery is used for correcting refractive errors such as astigmatism, myopia, and hyperopia. Many people with astigmatism have found LASIK eye surgery to be a safe and effective method of vision correction.
For some reason, there is a “stigma” about astigmatism when it comes to LASIK. However, most patients with astigmatism can have laser refractive surgery. Most of this stems from the fact that it was the first type of vision problem approved by the FDA for LASIK.
While most people who have astigmatism can have LASIK, some people have too much astigmatism for the laser to correct. They, however, sometimes can have an additional procedure called astigmatic keratectomy (AK) to correct any remaining astigmatism.
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Astigmatism | Causes and Treatment
A refractive error is an eyesight problem. Refractive errors are a common reason for reduced level of eyesight (visual acuity).
Refraction refers to the bending of light, in this case by the eye, in order to focus it. A refractive error means that the eye cannot focus light on to the retina properly. This usually occurs either due to abnormalities in the shape of the eyeball, or because age has affected the workings of the focusing parts of the eye.
There are four types of refractive error:
- Short sight (myopia).
- Long sight (hypermetropia).
- Age-related long sight (presbyopia).
- Astigmatism (a refractive error due to an unevenly curved cornea).
In order to understand refractive errors fully, it is useful to know how we see.
When we look at an object, light rays from the object pass through the eye to reach the retina. This causes nerve messages to be sent from the cells of the retina down the optic nerve to the vision centres in the brain. The brain processes the information it receives, so that in turn, we can see.
Light rays come off an object in all directions, as they result from the light around us from sun, moon and artificial light bouncing back off the object. The part of this bounced light that comes into the eye from an object needs to be focused on a small area of the retina. If this doesn't happen, what we look at will be blurred.
The cornea and lens have the job of focusing light. The cornea does most of the work, as it (refracts) the light rays which then go through the lens, which finely adjusts the focusing.
The lens does this by changing its thickness. This is called accommodation. The lens is elastic and can become flatter or more rounded.
The more rounded (convex) the lens, the more the light rays can be bent inwards.
The shape of the lens is varied by the small muscles in the ciliary body. Tiny string- structures called the suspensory ligaments are attached at one end to the lens and at the other to the ciliary body. This is a bit a trampoline with the central bouncy bit being the lens, the suspensory ligaments being the springs and the ciliary muscles being the rim around the edge.
When the ciliary muscles in the ciliary body tighten, the suspensory ligaments slacken, causing the lens to become fatter. This happens for near objects. For looking at far objects, the ciliary muscle relaxes, making the suspensory ligaments tighten, and the lens thins out.
More bending (refraction) of the light rays is needed to focus on nearby objects, such as when reading. Less bending of light is needed to focus on objects far away.
The cornea at the front of the eye is not perfectly rounded but is curved, a little a rugby ball. When this curve is too great, or curves in the wrong direction, astigmatism occurs. Light rays coming through the cornea and lens are not focused on to one sharp spot on the retina but are spread. This lack of 'point focus' means that images received by the brain are blurred.
Astigmatism is a bit more complicated than either short sight (myopia) or long sight (hypermetropia), as there is a problem with the focus of light in two different directions (both depth-ways and sideways). However, the other refractive errors, the end result is the same: there is blurring of vision which can impair eyesight.
The two eyes are usually not the same (ie if both eyes have astigmatism they may not be affected in the same line of vision or to the same degree). If the condition is mild, the brain will compensate for the difference between the two eyes, although this can cause eye strain and headaches.
Although astigmatism is very common (about 9 in 10 people have some degree of astigmatism), it does not always cause a problem.
Astigmatism is usually present at birth. It can result from an injury, scar or operation to the eye, particularly if the corneal surface is damaged. It can also result from anything pressing persistently on the surface of the cornea (such as a large lump on the eyelid) which pushes it shape.
Astigmatism can run in families and seems to be more common in premature or low-birth-weight babies. This may be because the cornea did not have enough time to develop properly in the womb.
Problems with the structure of the cornea can cause astigmatism. About 1 in 5 people with Down's syndrome have this problem and have significant astigmatism. Other corneal disorders develop throughout life. The most common of these is a condition called keratoconus. This can cause significant astigmatism, as well as short sight (myopia) and corneal scarring.
For most people, astigmatism is a very mild, minor problem which may not even be noticed. However, with more advanced astigmatism, there can be a variety of symptoms including blurred vision, light sensitivity (photophobia), eye strain and fatigue (especially after long periods of concentration, such as when using a computer) and headaches.
Other symptoms can include difficulty seeing one colour against another (contrast), and distorted images, such as lines which lean to one side. Severe astigmatism can cause double vision.
Astigmatism often occurs along with either short sight (myopia), long sight (hypermetropia) or age-related long sight (presbyopia). See the separate leaflets called Short Sight – Myopia, Long Sight – Hypermetropia and Age-related Long Sight (Presbyopia) for more details.
Astigmatism in only one eye may cause lazy eye (amblyopia) if present from birth. The affected eye does not 'learn' how to see because the brain ignores the signals it receives. Amblyopia can be treated with eye patching if diagnosed early enough, before the vision pathways in the brain are fully developed. See the separate leaflet called Amblyopia (Lazy Eye) for more details.
In many cases the symptoms of astigmatism are so mild that no treatment is needed. If vision is more significantly affected, glasses, contact lenses or surgery can correct the vision.
The simplest, cheapest and safest way to correct a regular astigmatism is with glasses. The lenses of the glasses adjust the direction of the incoming light rays, correcting the uneven curve of the cornea.
There is an enormous choice of spectacle frames available, to suit all budgets. An irregular astigmatism cannot be corrected by a lens.
Glasses are seen as more acceptable these days and younger people may even regard them as a fashion accessory.
These do the same job as glasses and are often the best option for astigmatism. Toric lenses are used. Contact lenses sit right on the surface of the eye. Many different types of contact lenses are available.
Lenses may be soft or rigid gas-permeable. They can be daily disposable, extended wear, monthly disposable, or non-disposable.
Your optician can advise which type is most suitable for your eyes and your prescription.
Contact lenses tend to be more expensive than glasses. They require more care and meticulous hygiene. They are more suitable for older teenagers and adults, rather than very young children.
Surgery is an option for some people to cure their astigmatism and any associated short or long sight. Generally, these operations are not available on the NHS. Laser eye surgery is expensive but offers the chance to restore normal sight permanently. The procedure is generally painless.
Complete and permanent resolution of the astigmatism is possible in a number of people. Others have a significant improvement even though perfect vision is not achieved, and glasses or contact lenses may still be needed.
A small number of people develop complications. Some develop hazy vision, a problem with night vision, or problems with bright light haloes in their peripheral (edge) vision.
Many private companies advertise laser eye surgery. Before embarking upon this type of treatment you should do some research. You only have one pair of eyes and you need to find the best treatment for you. This may not be the cheapest.
Try to go with personal recommendations, preferably a recommendation by an NHS eye surgeon (ophthalmologist).
It is important that you know your facts – the failure rate, the risk of complications, level of aftercare and what the procedure involves, before submitting yourself to an irreversible, costly treatment.
Several types of laser surgery have been developed. These include: LASIK®, PRK® and LASEK®. They are all similar, typically taking about ten minutes per eye and aiming to reshape the cornea by using the laser to remove a very thin layer of corneal tissue. The reshaping of the cornea allows the refraction of the eye to be corrected.
- LASIK stands for Laser-Assisted In situ Keratomileusis. This is the most popular form of laser eye surgery.
- The laser is used to lift and remove a thin flap of the cornea.
- This helps to flatten the cornea so that the light rays can be focused further back and on to the retina.
- The flap is then replaced and sticks spontaneously to the underlying cornea. The flap serves as a natural bandage, keeping the eye comfortable as it heals. Healing occurs relatively quickly.
- This is the most popular and common type of laser eye surgery.
- Vision recovery time is said to be around 24 hours.
For people who are not suitable for LASIK® the following two options are sometimes offered.
- PRK stands for Photo-Refractive Keratectomy.
- During PRK®, instead of creating a corneal flap as in LASIK®, the surgeon completely removes the extremely thin outer layer of the cornea, using an alcohol solution, a 'buffing' device or a blunt surgical instrument. The underlying cornea is then reshaped with a laser. A new epithelial layer grows back within five days.
- The healing time in PRK® is faster than in LASEK®.
- LASEK stands for LAser Sub-Epithelial Keratomileusis.
- The LASEK® procedure involves taking a thinner flap of corneal epithelium than in LASIK®. The cornea underneath is then treated as in LASIK® and the thinner flap is repositioned and held in place with a bandage contact lens.
- The hinged flap made in LASEK® surgery is much thinner than the corneal flap created in LASIK® (which contains both epithelial and deeper stromal tissues).
- The LASEK® technique lessens the lihood of removing too much cornea. There is also slightly less risk of developing dry eyes afterwards.
- Patients with a naturally thin cornea may be more suited to this treatment.
- LASEK® can be a better option for patients with a high degree of myopia, which requires more tissue removal from the central cornea.
- LASEK® tends to be more painful and discomfort can last longer than with LASIK®. Visual recovery time can be up to a week.
- In some cases, the thin flap created during LASEK® is not strong enough to be replaced and will be removed completely as it would have been in PRK.
- The alcohol solution used during LASEK® can irritate and slow the healing process immediately after surgery.
Side-effects of all laser surgery may include blurred vision, over-correction or under-correction of short-sight, eye infection and dry eyes.
There are other methods available – most are variants of laser surgery. Implantable contact lenses (refractive lens exchange) and corneal grafts are options in very severe or specialised cases of astigmatism.
This depends on your age, your family history and any pre-existing medical conditions.
People at high risk of sight problems need more frequent eyesight checks. If you have diabetes, raised pressure in the eye (glaucoma), macular degeneration, or a family history of these conditions, you should check to see what your optician recommends about regular check-ups.
If you fall into a high-risk group, you should have at least a two-yearly (biennial) eye examination if you are over 50 years of age, and a yearly (annual) one if you are over 60 years of age.
If you have more than one risk factor then an eyesight check is recommended at least every three years once you reach 40 years of age.
Low-risk people with no symptoms of an eyesight problem, do not need to have their eyes tested so frequently. If you fall in this group and are aged between 19 and 40 years, an eye test is needed every 10 years.
Between the ages of 41 and 55 years, it is recommended that you see an optician every five years.
At any age between 56 and 65 years, two-yearly checks are needed, dropping to annual checks in low-risk people who are aged 65 years or more.
What Exactly Is Astigmatism?
Astigmatism is a type of refractive error caused by the irregularities in the shape of a person’s cornea. In this condition, the eye fails to focus the light equally on the retina leading to blurred or distorted vision. It can be present at the time of birth, or can develop gradually in life.
Astigmatism is a common eye condition which usually occurs with myopia (nearsightedness) or hyperopia (farsightedness) and can be easily diagnosed with a simple eye exam.
Astigmatism is a refractive error and is not an eye disease or eye health issue.
Astigmatism is simply a problem with how the eye focuses light.
Astigmatism usually causes vision to be blurred or distorted to some degree at all distances. Some of its symptoms are eye strain, headaches, squinting and eye irritation.
What causes astigmatism?
Astigmatism is usually caused by an irregularly shaped cornea. Instead of the cornea having a symmetrically round shape ( a ball), it is shaped more an egg, with one meridian being significantly more curved than the meridian perpendicular to it.
(To understand what meridians are, think of the front of the eye the face of a clock. A line connecting the 12 and 6 is one meridian; a line connecting the 3 and 9 is another.)
The steepest and flattest meridians of an eye with astigmatism are called the principal meridians.
In some cases, astigmatism is caused by the distortion of shape of the lens inside the eye. This is called lenticular astigmatism, to differentiate it from the more common corneal astigmatism.
It's important to schedule an eye exam for your child to avoid vision problems in school from uncorrected astigmatism.
Worried about astigmatism? Find an eye doctor near you and schedule an appointment.
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3 types of astigmatism
There are three primary types of astigmatism:
- Myopic astigmatism. One or both principal meridians of the eye are nearsighted. (If both meridians are nearsighted, they are myopic in differing degree.)
- Hyperopic astigmatism. One or both principal meridians are farsighted. (If both are farsighted, they are hyperopic in differing degree.)
- Mixed astigmatism. One prinicipal meridian is nearsighted, and the other is farsighted.
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 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.
Astigmatism is detected during a routine eye exam with the same instruments and techniques used for the detection of nearsightedness and farsightedness.
Your eye doctor can estimate the amount of astigmatism you have by shining a light into your eye while manually introducing a series of lenses between the light and your eye. This test is called retinoscopy.
Astigmatism correction options
Astigmatism can usually be corrected with eyeglasses, contact lenses or refractive surgery.
Refractive surgery is one of the less common astigmatism correction options, however, since it is alaser procedure that changes the shape of your eyes, it comes with risks associated with most surgeries.
Astigmatism should be treated as soon as possible. Once diagnosed, regular visits to an eye doctor are required as astigmatism can fluctuate over time, making it necessary for prescriptions to be modified.
Find an eye doctor near you.
Astigmatism: Here’s What You Need To Know
Vision problems such as nearsightedness and farsightedness fortunately have names that make them pretty easy to understand. But have you ever wondered what astigmatism is?
What It Means To Have Astigmatism
To understand astigmatism we must first understand the process of how we are able to see. Put simply, light enters the eye, passing through the cornea–the clear surface that covers the front of the eye.
The cornea bends the light, and in conjunction with the lens, focuses it onto the retina at the back of the eye.
Receptors on the retina send signals which are processed by the brain, allowing us to form an image of what we are seeing.
In a normal eye the cornea is round, shaped a basketball, for example. In an eye with astigmatism, the cornea is oblong, shaped more a football. Because of its irregular shape, an eye with astigmatism focuses light onto several different points at the back of the eye, instead of precisely onto the retina. This causes blurred vision at all distances.
other refractive errors such as myopia and hyperopia (near and farsightedness), astigmatism usually occurs because of genetics. In other cases, it can also be caused by trauma to the eye or a disorder called keratoconus.
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Astigmatism Can Be Treated With Corrective Lenses
Despite its intimidating name, astigmatism is a fairly common vision problem. In fact, many of us have some level of astigmatism, but not severe enough to warrant corrective treatment.
If you are experiencing blurred vision, eye strain or headaches, come and see us! While these symptoms don’t always mean you have astigmatism, they are common signs of an uncorrected vision problem. Astigmatism is easily detected during a routine, comprehensive eye exam.
If you have astigmatism, there are a wide range of treatment options available such as glasses, contact lenses and even vision correction procedures. your visual and lifestyle needs, we can discuss which of these choices is best for you.
Talk To Us About Your Vision
Our priority is to keep you seeing clearly so you can enjoy this life to the fullest! As your trusted eye care providers, we can suggest the best possible solution for your individual needs. So, talk to us about astigmatism. We’re here to help!
The content on this blog is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of qualified health providers with questions you may have regarding medical conditions
What Does 20/20 Vision Really Mean? 3D Entertainment And Our Eyes
Astigmatism | Mooresville Optometrist
In a perfect world, we would all be born with perfect eyes — but sometimes the corneas or lenses of the eyes are less than ideally shaped, and in many cases the result is astigmatism.
Even small abnormalities in the curvature of these structures can create visual distortion, eye strain and other uncomfortable inconveniences. But the good news is that you don't have to put up with these irregularities in your eyesight.
Here at Eye Care Center Mooresville, we have the skills, experience and technology to provide precise, effective corrections for this disorder.
How Corneal Defects Cause Astigmatism
Astigmatism belongs to the family of vision problems known as refractive errors. A refractive error occurs when the light that enters the eye isn’t focused correctly to direct images directly onto the retina.
In refractive errors such as nearsightedness and farsightedness, either the cornea or the eyeball itself may be too long or too short to allow for normal refraction.
But in astigmatism, the refractive error is due to small pits, “dents” or other imperfections in the normally spherical curve of the cornea. (There is also a variant called lenticular astigmatism, in which the imperfections occur in the shape of the lens.
) These little flaws can cause big problems, including areas of blurry vision that can have you straining to see clearly. To add insult to injury, you can have astigmatism on top of another refractive error.
Diagnosis and Solutions at Our Optometry Clinic
A comprehensive eye and vision exam at our optometry clinic can determine whether you're suffering from astigmatism. Your optometrists, Dr. Ed Mills and Dr.
Christopher Mills, can use retinoscopy to observe the refractive pattern produced at the front of the eye, along with keratometry to analyze your corneal curvature.
We can then map the areas of distortion relative to imaginary lines called meridians, measuring the sphere (or primary meridian of distortion) and cylinder (or secondary meridian of distortion) to create an accurate corrective prescription.
Once your optometrist knows exactly how to compensate for your individual case of astigmatism, it's time to select corrective lenses. Eyeglasses generally do an excellent job of correcting astigmatism.
Contact lenses can also correct astigmatism, although you might need specialized lenses such as toric or scleral contacts.
We can even provide pre-operative post-operative care for LASIK surgery to correct your astigmatism permanently.
Our Mooresville Clinic Holds the Answers to Your Astigmatism
Now that you know what astigmatism is and how we can correct your vision to compensate for it, take the next step toward a clearer, more accurate view of the world.
Call Eye Care Center in Mooresville at (704) 664-9121 to set up an evaluation and seek astigmatism treatment from either optometrist at our clinic.
In fact, if you buy one pair of glasses, we'll even let you get a second pair at 50 percent off — so there's no better time to correct that annoying refractive error!
How Do You See the World if You Have Astigmatism?
Approximately one in three people experience astigmatism in the U.S. It is a type of refractive error, so it affects how the eye bends light. (Learn More)
This eye issue causes blurriness, so the images you are looking at appear fuzzy and unclear. (Learn More)Most people have this condition to some degree, but there are widely different levels of severity. (Learn More)
If astigmatism is making it hard to see clearly, there are treatment options. Corrective lenses are the most common treatment. (Learn More)
How Does Astigmatism Affect the Eyes?
When someone has astigmatism, the cornea has an irregular shape. In some cases, the lens of the eye has an abnormal curvature.
A healthy cornea is shaped a baseball, making it symmetrically round. When astigmatism is present, the cornea takes on the shape of a football.
When comparing perpendicular meridians, one is more curved than the other. The difference in curvature is typically significant.
The meridians are best described as the face of a clock. For example, the line that connects the 3 and 9 is a meridian. Another meridian is the line connecting the 6 and 12. With astigmatism, the principal meridians are the flattest and steepest meridians.
There are three astigmatism types.
- If both or one principal meridian is farsighted, someone has hyperopic astigmatism.
- If both or one principal meridian is nearsighted, someone has myopic astigmatism.
- If one principal meridian is farsighted and the other one is nearsighted, someone has mixedastigmatism.
Once someone is diagnosed with astigmatism, it is classified as irregular or regular. The principal meridians are not perpendicular with the irregular type, but they are perpendicular with the regular type. In most cases, astigmatism is the regular type affecting the cornea.
Why corneal shape differs among people remains unknown. However, there is ly an inherited element to the condition. In some cases, it can develop following an eye injury, disease, or surgery.
How Does Astigmatism Impact Vision?
Astigmatism leads to distorted or blurry vision at far and near distances.
Light focuses on multiple points instead of just one. At night when looking at lights, they appear to bounce off their primary location. For example, when looking at a stop light, the actual light appears fuzzy, and the light seems to reflect off it in multiple directions.
When looking at an object, it appears blurry and unclear. It has an abnormal softness and fuzziness to it. The edges of the object may appear undefined.
The vision issues that occur with astigmatism can also lead to the following symptoms:
- Areas of distorted vision
- Eye discomfort
- Blurry vision
- Squinting to see clearly
- Eye strain
What Are the Different Levels of Severity?
The severity of astigmatism is stated in diopters.
- 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.
Astigmatism Treatment Options
When astigmatism is slight, people often do not need treatment. However, when it is impacting vision, a comprehensive eye examination is needed to get a definitive diagnosis. From here, the doctor can determine which treatment is appropriate to improve vision.
Corrective lenses are commonly prescribed to people who have astigmatism. They work by counteracting a cornea or lens curvature. Eyeglasses for astigmatism have lenses that compensate for the corneal abnormality.
Contact lenses can also be used for astigmatism. They come in a variety of styles and types.
- Disposable soft
- Rigid, gas permeable
- Extended wear
Contact lenses are also used as part of the orthokeratology procedure. For this procedure, the doctor has the patient wear rigid contact lenses. They are worn for many hours a day. The purpose is to even out the curvature of the eyes. Once the curvature is evened out, people still need to wear their lenses to maintain the new shape, but they can wear them less frequently.
If someone stops wearing their contact lenses after this procedure, the curvature correction does dissipate, and the cornea eventually reverts back to its abnormal shape. Because of this, people have to wear the lenses long term to maintain the benefits of the procedure.
There are four types of refractive surgery that can be used for astigmatism.
- LASIK: This works to sculpt the corneal shape so light properly focuses in the eye. It involves making a flap in the cornea and replacing the flap after using a laser for the reshaping.
- PRK: This procedure involves removing the epithelium and then changing the corneal shape using a laser.
- LASEK: LASEK is similar to PRK, but the epithelium is not removed. The doctor uses it to create a flap and them puts it back into place after using the laser to reshape the cornea.
- Epi-LASIK: This procedure is a variation of LASEK. The epithelium is separated using a blade instead of alcohol, and a laser then reshapes the cornea.
Astigmatism is a common refractive error. It occurs in varying degrees and affects vision differently depending on severity.
It’s one of the eye conditions that is easily corrected with corrective lenses or laser surgery.
Eye Health Statistics. American Academy of Ophthalmology.
Astigmatism. American Optometric Association.
Astigmatism. All About Vision.
What Is Astigmatism? American Academy of Ophthalmology.
Facts About Astigmatism. National Eye Institute.
Astigmatism. Mayo Clinic.