Astigmatism: Symptoms, Causes & Treatment Options — Complete Guide
Updated: 2 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Quick Answer: What Is Astigmatism?
Astigmatism is a common, generally treatable imperfection in the curvature of the eye. The cornea or lens is egg-shaped rather than round, so light does not bend equally and vision is blurred at all distances. It often occurs with nearsightedness or farsightedness and is usually present from birth. Treatment is corrective lenses or refractive surgery such as LASIK. [1]
What the research says
Laser surgery corrects astigmatism well, and SMILE and LASIK perform alike. In a meta-analysis of 17 studies (1,985 eyes), both SMILE and LASIK gave effective, predictable correction of severe astigmatism with generally equivalent outcomes, although SMILE tended toward undercorrection and LASIK carried a greater chance of postoperative spherical aberration. (Song et al., Am J Ophthalmol, 2022) [3]
No single laser procedure wins on efficacy. Across 17 studies (5,686 treated eyes) comparing transepithelial PRK with LASIK and SMILE, there were no significant differences in efficacy or predictability, and LASIK showed a safety advantage over transepithelial PRK in the astigmatism and low-to-moderate myopia subgroup. The authors conclude the choice should rest on patient characteristics, laser availability, complication risk, and surgeon experience. (Serfözö et al., Eur J Ophthalmol, 2026) [4]
Astigmatism is common in children, though less so than nearsightedness. In 43 studies of Indian school children, the pooled prevalence of refractive errors was 11%: myopia 8%, astigmatism 3%, and hyperopia 1%. (Kumar et al., Ophthalmic Epidemiol, 2025) [5]
Astigmatism at a Glance
What it is: Imperfection in the eye's curvature — cornea or lens egg-shaped instead of round.
What it causes: Blurred distance and near vision; a type of refractive error.
Symptoms: Blurred/distorted vision, eyestrain, headaches, night vision trouble, squinting.
When it starts: Often present at birth; can develop after eye injury, disease, or surgery.
Types: Corneal (cornea mismatched) or lenticular (lens mismatched); often combined with nearsightedness or farsightedness.
Not caused by: Reading in poor light, sitting too close to the TV, or squinting.
How diagnosed: Complete eye exam + refraction measuring how the eyes bend light.
Treatment: Corrective lenses (glasses, contacts) or refractive surgery (LASIK and similar).
What Is Astigmatism?
Astigmatism (uh-STIG-muh-tiz-um) is a common and generally treatable imperfection in the curvature of the eye that causes blurred distance and near vision.
It occurs when either the front surface of the eye (cornea) or the lens inside the eye has mismatched curves. Instead of having one curve like a round ball, the surface is egg-shaped. This causes blurred vision at all distances.
Astigmatism is often present at birth and may occur in combination with nearsightedness or farsightedness. Often it's not pronounced enough to require corrective action. When it is, the treatment options are corrective lenses or surgery.
What are the five warning signs of astigmatism?
Astigmatism may cause five warning signs: blurred or distorted vision, eyestrain or discomfort, headaches, difficulty with night vision and squinting.
Blurred or distorted vision
Eyestrain or discomfort
Headaches
Difficulty with night vision
Squinting
When to See a Doctor
See an eye doctor if your eye symptoms detract from your enjoyment of activities or interfere with your ability to perform everyday tasks. An eye doctor can determine whether you have astigmatism — and if so, to what degree — and then advise you of your options to correct your vision.
Children and Adolescents
Children may not realize their vision is blurry, so they need to be screened for eye disease and have their vision tested by a pediatrician, an ophthalmologist, an optometrist, or another trained screener at these ages and intervals:
During the newborn period
At well-child visits until they reach school age
During school years, every 1 to 2 years — at well-child visits, at the eye doctor, or through school or public screenings
What Causes Astigmatism?
The eye has two structures with curved surfaces that bend (refract) light onto the retina, which makes the images:
The cornea — the clear front surface of the eye along with the tear film
The lens — a clear structure inside the eye that changes shape to help the eye focus on near objects
How a Perfect Eye Focuses
In a perfectly shaped eye, each of these elements has a round curvature, like the surface of a smooth ball. A cornea or lens with such curvature bends all incoming light equally to make a sharply focused image directly on the retina at the back of the eye.
A Refractive Error
If either the cornea or the lens is egg-shaped with two mismatched curves, light rays aren't bent the same way — which means that two different images form. These two images overlap or combine and result in blurred vision. Astigmatism is a type of refractive error.
Astigmatism occurs when the cornea or lens is curved more steeply in one direction than in another. The two types:
Corneal astigmatism: The cornea has mismatched curves.
Lenticular astigmatism: The lens has mismatched curves.
Either type can cause blurred vision, and the blur may occur more in one direction: horizontally, vertically, or diagonally.
When Does It Develop?
Astigmatism may be present from birth, or it may develop after an eye injury, disease, or surgery. Importantly, astigmatism isn't caused or made worse by:
Reading in poor light
Sitting too close to the television
Squinting
Astigmatism Alongside Other Refractive Errors
Astigmatism may occur in combination with other refractive errors:
Nearsightedness (myopia): The cornea is curved too much or the eye is longer than usual; light is focused in front of the retina. Result: distant objects seem blurry.
Farsightedness (hyperopia): The cornea is curved too little or the eye is shorter than usual; light never comes to a focus at the back of the eye. Result: nearby objects seem blurry.
What are the risk factors for astigmatism?
Risk factors for astigmatism include genetics, an eye injury, the eye condition keratoconus and previous eye surgery.
Genetics: Astigmatism can be hereditary — passed down from parents.
Eye injury: Trauma to the eye can change its curvature.
Keratoconus: Risk is higher in people with keratoconus — an eye condition in which the cornea thins and bulges outward.
Eye surgery: Astigmatism can happen after eye surgery.
How is astigmatism diagnosed?
Astigmatism is diagnosed with an eye exam. A complete eye exam involves two parts:
A series of tests to check eye health
A refraction — a test that determines how the eyes bend light
Your eye doctor may use various instruments, aim bright lights directly at your eyes, and ask you to look through several lenses. These tests examine different aspects of your eyes and vision and determine the prescription needed to provide clear vision with eyeglasses or contact lenses [2].
How is astigmatism treated with lenses or surgery?
The goal of treating astigmatism is to improve vision clarity and eye comfort. There are two treatment paths: corrective lenses or refractive surgery [2].
Corrective Lenses
Wearing corrective lenses treats astigmatism by counteracting the uneven curvatures of your cornea or lens:
Eyeglasses: Lenses compensate for the uneven shape of the eye and bend light into the eye properly. They can also correct other refractive errors such as nearsightedness or farsightedness.
Contact lenses: Like eyeglasses, can correct most astigmatism; available in a variety of types and styles. Wearing contact lenses for extended periods increases the risk of infection — ask your eye doctor about the pros, cons, and risks to find what's best for you.
Refractive Surgery
Refractive surgery improves vision and reduces the need for eyeglasses or contact lenses. An eye surgeon uses a laser beam to reshape the curves of the cornea, correcting the refractive error. Before surgery, doctors will evaluate you to determine if you're a candidate.
LASIK (laser-assisted in-situ keratomileusis): A thin, hinged flap is made in the cornea; an excimer laser sculpts the cornea's shape; the flap is repositioned.
LASEK (laser-assisted subepithelial keratectomy): No flap — the cornea's thin protective cover (epithelium) is loosened with a special alcohol; an excimer laser changes the curvature; the epithelium is repositioned.
PRK (photorefractive keratectomy): Similar to LASEK, except the surgeon removes the epithelium; it grows back naturally, conforming to the cornea's new shape; a bandage contact lens may be needed for a few days.
Epi-LASIK: A variation of LASEK — a mechanized blunt blade (instead of alcohol) separates a very thin sheet of epithelium; a laser reshapes the cornea; the epithelium is repositioned.
SMILE (small-incision lenticule extraction): A newer procedure — a laser makes a lens-shaped bit of tissue (lenticule) below the cornea's surface, removed through a very small incision; approved only for treating mild nearsightedness for now.
Other types of refractive surgeries include clear lens extraction and implantable contact lenses.
There is no one best method for refractive surgery. You should make a decision only after a complete evaluation and a thorough discussion with your surgeon.
Possible Complications After Refractive Surgery
Be sure to discuss the potential risks and benefits with your eye doctor:
Undercorrection or overcorrection of your initial problem
Visual side effects, such as a halo or starburst appearing around lights
Dry eye
Infection
Corneal scarring
Rarely, vision loss
How should you prepare for an astigmatism appointment?
Preparing for an astigmatism appointment means knowing which eye specialist you'll see and listing your symptoms, personal information, medications and questions.
Ophthalmologist (M.D. or D.O.): Full eye care: complete eye evaluations, prescribing corrective lenses, diagnosing and treating common and complex eye disorders, performing eye surgery.
Optometrist (O.D.): Eye health examinations, prescribing corrective lenses, diagnosing and treating some eye conditions.
Optician (licensed in some states): Helps fit people for eyeglasses following prescriptions — not trained to diagnose or treat eye disease.
What You Can Do
List any symptoms you're experiencing, including any that may seem unrelated to the reason for your appointment
List key personal information, including any major stresses or recent life changes
Make a list of all medications, vitamins, or supplements you're taking, including doses
List questions to ask your doctor
Questions to Ask the Doctor
What is likely causing my symptoms?
Other than the most likely cause, what are other possible causes for my symptoms?
What kinds of tests do I need?
Is my condition likely temporary or chronic?
What is the best course of action?
What are the alternatives to the primary approach that you're suggesting?
I have other health conditions — how can I best manage them together?
Are there any restrictions that I need to follow?
Should I see a corneal specialist?
Will my insurance company pay for surgical procedures?
Do you have any brochures or other printed material I can take home? What websites do you recommend?
Questions the Doctor Will Likely Ask
When did you first begin experiencing symptoms?
Have your symptoms been continuous or occasional?
How severe are your symptoms?
What, if anything, seems to improve your symptoms?
What, if anything, appears to worsen your symptoms?
FAQ: Astigmatism Questions People Also Ask
What is astigmatism?
Astigmatism is a common and generally treatable imperfection in the curvature of the eye, where the cornea or lens is egg-shaped instead of round, causing blurred vision at all distances. It is a type of refractive error and is often present from birth.
What are the symptoms of astigmatism?
The main symptoms are blurred or distorted vision, eyestrain or discomfort, headaches, difficulty with night vision, and squinting. If these symptoms interfere with everyday tasks, see an eye doctor.
What causes astigmatism?
Astigmatism occurs when the cornea or the lens has two mismatched curves instead of one round curve, so light rays form two overlapping images rather than one sharp focus. It can be present from birth or develop after an eye injury, disease, or surgery.
Does reading in the dark or sitting close to the TV cause astigmatism?
No. Astigmatism isn't caused or made worse by reading in poor light, sitting too close to the television, or squinting.
How is astigmatism diagnosed?
Astigmatism is diagnosed with a complete eye exam that includes a series of eye health tests and a refraction, which measures how your eyes bend light. These tests determine the exact prescription needed for clear vision with glasses or contact lenses.
How is astigmatism treated?
The goal of treatment is clearer vision and greater eye comfort, using corrective lenses (eyeglasses or contact lenses) or refractive surgery such as LASIK, LASEK, PRK, Epi-LASIK, or SMILE, in which a laser reshapes the cornea.
Can children have astigmatism?
Yes — astigmatism is often present at birth, and children may not realize their vision is blurry. That's why they should be screened during the newborn period, at well-child visits until school age, and every 1 to 2 years during the school years.
Conclusion
By now, you understand the essentials of this common, treatable condition:
It's about shape, not disease. Astigmatism is simply an egg-shaped cornea or lens — two mismatched curves that split one image into two overlapping ones, blurring vision at every distance.
It's nothing you did wrong. It's often present from birth or triggered by genetics, injury, keratoconus, or surgery — not by reading in dim light or sitting too close to the TV.
The fix is well-proven. Corrective lenses counteract the uneven curvature, and laser surgery reshapes it — so most people see clearly again.
This guide has walked you through the symptoms, the round-versus-egg mechanics, the risk factors, the eye exam and refraction, the full treatment menu, and how to prepare for your appointment.
The information in this article is for general educational purposes only and does not replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider about your individual condition.
Related Reading
SMILE Eye Surgery: How It Works, Candidates and Recovery explains SMILE laser eye surgery.
LASIK Eye Surgery: Procedure, Recovery and Results explains how LASIK corrects vision.
Learn more in our guide to Eye Exam: What Happens, Tests Included and How Often to Go.
Visual Acuity Test (Snellen Chart): How It Works and What 20/20 Means explains the eye-chart test that measures how sharply you see.
Retinoscopy: How Eye Doctors Measure Your Prescription explains the light-reflex eye test used to measure a glasses prescription.
Corneal Topography: Mapping the Cornea and Reading the Results explains the eye test that maps the shape of the cornea.
Keratometry: Measuring Corneal Curve for Astigmatism and Cataract Surgery explains the test that measures the curve of the cornea.
References
Mayo Clinic Staff. Astigmatism - Symptoms and causes. Mayo Clinic. April 30, 2025. https://www.mayoclinic.org/diseases-conditions/astigmatism/symptoms-causes/syc-20353835
Mayo Clinic Staff. Astigmatism - Diagnosis and treatment. Mayo Clinic. April 30, 2025. https://www.mayoclinic.org/diseases-conditions/astigmatism/diagnosis-treatment/drc-20353838
Song J, Cao H, Chen X, et al. Small Incision Lenticule Extraction (SMILE) Versus Laser Assisted Stromal In Situ Keratomileusis (LASIK) for Astigmatism Corrections: A Systematic Review and Meta-analysis. Am J Ophthalmol. 2022;247:181-199. PMID: 36410469. DOI: 10.1016/j.ajo.2022.11.013.
Serfözö A, Abu Dail Y, Munteanu C, et al. The efficacy, safety and predictability in transepithelial photorefractive keratectomy versus LASIK/SMILE: A meta-analysis. Eur J Ophthalmol. 2026;36(4):837-855. PMID: 41734035. DOI: 10.1177/11206721261425379.
Kumar V, Soni M, Rajagopal V, et al. The Prevalence of Refractive Errors in Indian School Children: A Systematic Review and Meta-Analysis. Ophthalmic Epidemiol. 2025;33(2):162-171. PMID: 39998413. DOI: 10.1080/09286586.2025.2450346.
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