An astigmatism often begins early in life, unlike many other vision problems that develop later. In fact, most people are believed to have at least a small degree of astigmatism in one or both eyes.
In a recent study of 2,523 American children ages 5 to 17 years, more than 28 percent had a degree of astigmatism that required treatment, such as corrective glasses or contact lenses. Surprisingly, astigmatism seems to be tied to ethnic background; Asian and Hispanic people tend to have the highest rates, followed by Caucasians.
A slight astigmatism isn’t always a problem, however, and doesn’t necessarily change someone’s vision. You only need to see your doctor when the astigmatism becomes bad. Factors may include scarring in the eye or genetics.
Is an astigmatism preventable, or can you lower your risk for developing one in any way? Experts think that genetics, uncorrected eyesight as a child, eye disease, or an impact to the eye raise the odds of an astigmatism. The most common treatments for astigmatism include early intervention to prevent vision from getting worse and glasses or contact lenses. In a small percentage of cases, specialists recommend LASIK surgery. If you already have vision problems, or a family history of astigmatism, eat a nutrient-dense diet with lots of vitamins and antioxidants that protect the eyes.
What Is Astigmatism?
The definition of astigmatism is “a defect in the eye or in a lens caused by a deviation from spherical curvature. This results in distorted images, as light rays are prevented from meeting at one common focus.”
In other words, vision problems that result from an astigmatism are due to a “refractive error,” or how light hits the eye. Astigmatism is not an eye disease, such as glaucoma, because the affected eye itself can be perfectly “healthy.” (01) It’s also not usually age-related, as it can affect younger people who otherwise have no nerve damage, such as neuropathy due to diabetes, which often damages the eyes.
An astigmatism is due to nerve damage or other causes. Light reflects and focuses abnormally, so images are not as crisp or clear as they could be.
Common Astigmatism Symptoms
The most common signs and symptoms of astigmatism include: (02)
- Blurred vision, especially around the edges of an object. Blurred vision can affect both near and distant vision.
- Double images or distorted images. When an astigmatism is bad, some people describe seeing as if they are viewing image through glass that has an irregular surface.
- Headaches, especially when squinting often.
- Eye strain or eye fatigue.
- Inability to see both near and distant objects without squinting. This can cause pain in the head or near the eyes after reading, being on a computer, or trying to focus.
- Blurring and pain usually become worse when reading small print and towards the end of the day, after trying to focus for many hours.
- Letters or shapes can appear thin or thinner than normal, compressed, stretched, or tilted. You might see better in some directions than others (vertically, horizontally or diagonally) or recognize some letters or shapes more easily than others (O versus X).
Risk Factors and Causes For Astigmatism
Here’s an overview of how an abnormal eye shape and eye function causes an astigmatism:
- The astigmatism causes light not to focus to a single point on the part of the eye called the retina. This causes eyesight that is irregular and distorts images. The American Academy of Ophthalmology states, “Normally, the cornea and lens of the eye are smooth and curved equally in all directions, helping to focus light rays sharply onto the retina at the back of your eye. However, if your cornea or lens isn’t smooth and evenly curved, light rays aren’t refracted properly.” (03)
- The retina usually focuses light in one single, small location to produce clear vision; however, due to the shape of an eye that has an astigmatism, many focal points occur. These focal points can develop in both the front of the retina or behind it, or sometimes both, all of which cause blurriness.
- Most people with an astigmatism have an abnormally shaped cornea that is not symmetrical like a “normal” eye is. Eyes that produce clear vision have a mostly uniform, round shape much like a ball or sphere. Astigmatic eyes are shaped “more like a football;” there’s a bigger curve in one part of the eye than the other. This is called “Corneal astigmatism.”
- The steepest and flattest meridians of an astigmatic eye are the “principal meridians.” The steeper/flatter they are, the more that vision will be affected.
- Some people have “Lenticular astigmatism,” an abnormal shape of the eye’s lens, rather than the cornea. This is less common than corneal astigmatism.
What causes either the cornea or lens to become abnormally shaped in some people, causing an astigmatism? Root causes and risk factors for astigmatism include:
- Genetics. The VisionWeb website states: “Most people have some degree of astigmatism, which is usually present at birth and is believed to be hereditary.” (04)
- An eye injury, which can cause scarring in the eyes and abnormal development of eye muscles.
- Scarring on the cornea (located at the front of the eye) for other reasons, such as healing poorly after eye surgery. Cases of severe astigmatism are sometimes due to surgical procedures that involve cutting the cornea, such as those made by laser to correct nearsightedness (myopia). Other causes can be scarring after operations carried out on the extra-ocular muscles to correct squinting or headaches.
- Accidents that don’t directly involve the eyes, such as car accidents or impacts that cause whiplash, can also trigger astigmatism in some patients. The way the eyes work can change if injuries affect the neck muscles that are connected with the extra-ocular muscles.
- Keratoconus, a disease that causes a gradual thinning of the cornea. (05) Over time this can make your normally round cornea more cone-shaped.
Will habits like reading in dim light, using a computer screen for many hours, or watching too much TV raise your risk for an astigmatism? While there’s debate over how much these habits may get worse or contribute to common vision problems, most experts think it’s “a myth” that they cause an astigmatism. (06) What does seem likely is that these factors will make symptoms like eyestrain or even headaches worse.
Nearsighted vs. Farsighted: How Are They Different?
According to the Wilmer Eye Institute at John Hopkin’s University, nearsightedness (also called myopia) is a condition that makes it difficult to see objects far away. Farsightedness is the opposite; it means difficulty seeing images close up. (07)
- Nearsightedness is a very common condition that affects tens of millions of Americans, even many from a very young age. An elongation of the eyeball that occurs over time, distorting the normal “sphere” shape of the eyeball, usually causes the condition. It’s estimated that about half of those with myopia (nearsightedness) also have an astigmatism and that the conditions are linked.
- Farsightedness (also called hyperopia) is the opposite of myopia. A shortening of the eyeball usually causes it.
- Astigmatism can be due to either nearsightedness/myopia or farsightedness/hyperopia. Sometimes both can contribute at the same time, depending on the specific slope and shape of the eye.
- Both nearsightedness and farsightedness cause changes in how the cornea and retina receive and reflect light from the environment. This results in blurred areas, termed “refractive errors,” trouble reading text and so on.
The diagnosis will be one of three primary types of astigmatism, depending on nearsightedness or farsightedness:
- Myopic astigmatism: Caused by nearsightedness, with both primary meridians of the eye being myopic (although sometimes to different degrees).
- Hyperopic astigmatism. One or both principal meridians of the affected eye are farsighted.
- Mixed astigmatism. One principal meridian is nearsighted, but the other is farsighted.
- Most astigmatisms are a “regular corneal astigmatism.” The shape of the cornea causes blurred vision. The principal meridians of the eyes are “regular” because they are 90 degrees apart (perpendicular to each other, as opposed to abnormally aligned or “irregular”). The prevalence of myopic astigmatism is believed to be much higher than hyperopic; in fact studies have found that double the amount of people are likely have myopic astigmatism.
Conventional Treatment For Astigmatism
Slight astigmatisms are very common and usually don’t need to be corrected until they start causing vision changes. Symptoms are normally treatable using contact lenses or surgery; however, the condition itself is chronic and therefore usually life-long.
Patients who think they might have an astigmatism should always see an ophthalmologist, a medical professional who specializes in vision and treating the eyes, in order to discuss treatment options.
- Treatments such as special eyeglasses or contact lenses that can help correct sight in those with vision problems will require a medical diagnosis and prescription.
- Usually no invasive lab tests are needed to make a diagnosis; however, other tests like taking close-up photos of the affected eyeball will likely be performed.
- The patient reads rows of increasingly smaller letters of The Snellen Test Chart. Many ophthalmologists also diagnose a decline in vision using refraction and retinoscopy tests or computerized devices that find the slope/shape of the eyes.
- Refractive surgery using a laser rarely is performed. This laser surgery changes the shape of your cornea, but the patient must have a healthy retina and limited scarring for it to work. LASIK surgery is one procedure in which a surgeon slices a flap into the cornea. Then a laser removes some tissue from beneath the sliced area to reshape the cornea and avoid light scattering.
Natural Treatments For Astigmatism
1. Early Detection & Keeping Up With Doctor’s Visits
Even children can have symptoms of an astigmatism, so it’s important to schedule an annual eye exam to detect one early and correct vision. The American Academy of Ophthalmology encourages vision screening in schools or at regular check-ups: “While adults with a higher degree of astigmatism may realize their vision isn’t as good as it should be, children who have astigmatism symptoms may not be aware they have this condition, and are unlikely to complain about blurred or distorted vision.”
Untreated astigmatism can become worse over time and contribute to problems like regular headaches, fatigue and lethargy. It can even cause difficulty concentrating and learning at school. Treat the problem in younger patients as early as possible; untreated vision problems are linked to poor performance in school and sports.
2. Eye Glasses & Contact Lenses
Although many patients today prefer to wear contact lenses over glasses, an astigmatism can be tricky to correct using contacts. If you already wear glasses for another vision problem (such as nearsightedness or farsightedness) then ideally your lenses also will be corrected for your astigmatism. Sometimes it takes some trial and error using different prescription glasses or contact lenses; not every patient reacts well at first to contact lenses or even glasses for astigmatism.
A special type of soft contact lens called soft torics is most often used to treat astigmatism symptoms. In the past only rigid contact lenses (RGPs, also called GP lenses) were used; however, newer toric lenses usually feel more comfortable.
Two of the most commonly used brands of toric contact lenses for treating astigmatism include Acuvue Oasys or Air Optix, both of which can be foun online with a prescription or at most doctors’ offices. However, toric lenses may be appropriate for people with mild-to-moderate cases, but not severe astigmatism. For severe cases, rigid contacts or glasses may be the best long-term option. (08)
Astigmatism lenses can be thick and uncomfortable in some cases. The eye doctor will choose a contact lens for the patient that balances the ideal correction level with what the patient can stand. There is no official prescription for a certain degree of astigmatism, so it’s really up to the eye specialist to decide which type of lenses will be best.
3. Preventing Worsening By Taking Care Of The Eyes
Most experts think that astigmatisms can not be prevented. Symptoms can become worse if the eyes are damaged or vision is not treated. (09) Reasons that astigmatism can progress include: (010)
- Eating a poor diet that causes inflammation or health conditions such as diabetes, blood pressure changes, etc.
- Exposure to the eyes of lots of UV light or blue light from electronic devices, which can make eye strain or headaches worse. Wear sunglasses or a hat while your face is in the sun to protect your eyes.
- Lack of nutrients in key vitamins, minerals and antioxidants that support eye health.
- Other factors that cause faster aging like a sedentary lifestyle, toxicity, drug use or smoking, etc.
Be sure to take care of your eyes by eating a nutrient-dense diet. Vitamins for your eyes include:
- Lutein and zeaxanthin
- Antioxidants like vitamin C, vitamin E and vitamin A
- Omega-3 fatty acids
- Other antioxidants like carotenoids, lycopene, glucosamine, etc.
All of these help stop free radical damage; prevent macular degeneration; lower the risk for cataracts; reduce glaucoma, eye fatigue, flare and light sensitivity; and make tissues in the eyes and other areas stronger. Some of the best foods that provide eye vitamins include: carrots, leafy greens, cruciferous vegetables, citrus fruits, sweet potatoes, green beans, eggs, all berries, papaya, mango, kiwi, melon, guava, corn, red bell peppers, peas, nuts, seeds, wild-caught seafood, grass-fed meat, bone broth and pasture-raised poultry. (011)
Precautions When Treating Astigmatism
See a doctor if your eyesight changes, or if you have headaches you think are tied to your vision. Prompt doctor’s visits are important. If your astigmatism gets worse quickly, you may be experiencing the start of a more serious eye disease. This can include keratoconus, when the center of the cornea thins and develops a cone-shaped bulge. It’s also best to rule out another problem like age-related macular degeneration, glaucoma, cataracts, scarring or neuropathy.
Final Thoughts On Astigmatism Symptoms, Causes & Remedies
- Astigmatism is a common vision problem that results from a “refractive error,” or how light abnormally hits the eye. Causes include an eye shape that is not symmetrical and round. Scarring in the eye or damage to the cornea and retina are other reasons.
- The most common signs and symptoms of astigmatism include blurred vision, seeing double images or distorted images and suffering from headaches, squinting and eyestrain.
- Astigmatism runs in families, can develop in childhood, often affects those with other vision problems (like nearsightedness) and tends to get worse when left untreated.
- Natural ways to treat astigmatism include contacts or glasses, early intervention to lower symptoms and preventing damage to the eyes that can come along with age or an unhealthy lifestyle.