Astigmatism changes the way the cornea or lens focuses light. An eye examination can identify it and explain the right correction.
A common difference in focusing
Astigmatism occurs when the cornea, the clear front surface of the eye, or the lens has different curvature in different directions. Light is not brought to a single sharp focus. Vision can look blurred or distorted at both near and far distances. It often occurs alongside short-sightedness or long-sightedness. Astigmatism overview; related focusing conditions.
What you might notice
Signs include squinting, tired eyes, headaches and difficulty seeing clearly at night. Mild astigmatism may cause little difficulty. In children, an uncorrected prescription can affect visual development, reading or concentration, even when they do not complain about their sight. An examination helps distinguish astigmatism from other causes of blur. Symptoms; children’s vision.
Sudden loss of vision or sudden severe eye pain requires immediate emergency assessment. Go to an eye emergency service or emergency department. Do not assume an abrupt change is caused by astigmatism or wait for a new glasses prescription. Urgent vision symptoms.
Why it happens
Astigmatism may be present from birth or develop during childhood or adulthood. Eye injury or surgery can also alter the focusing surfaces. In some people, astigmatism is associated with a corneal condition such as keratoconus. This is one reason an eye-health check matters as well as finding a clearer glasses prescription. Causes; associated conditions.
What an eye test measures
A vision chart checks clarity, while a refraction test compares different lenses to find the most useful correction. The examiner may also measure the cornea’s curvature with an instrument called a keratometer. These tests help characterize the astigmatism and guide lens choices. Assessment.
Treatment choices
Glasses are a common option. Contact lenses can also correct astigmatism, but they need appropriate fitting and careful hygiene. Some adults may be candidates for laser or other refractive procedures after assessment. Surgery has possible side effects and complications, and it is not suitable for everyone. Mild astigmatism that causes no visual difficulty may only need monitoring. Options and trade-offs.
When discussing correction, describe the tasks that are affected: looking between a screen and papers, reading road signs, working in dim light or playing sport. Bring your current glasses and any previous prescription, and explain whether the blur is new, changing or present mainly in one eye. This gives the consultation a practical starting point.
Astigmatism illustrated
Questions to ask
- Is my astigmatism stable, and is the cornea otherwise healthy?
- Would glasses or contact lenses suit my everyday needs better?
- If I am considering surgery, what limitations and risks apply?
- For my child, is the prescription affecting normal visual development?
Frequently asked questions
Can I have astigmatism and myopia together?
Yes. Astigmatism commonly occurs alongside myopia or hyperopia, and the prescription can correct both. Combined focusing errors.
Does every astigmatism prescription need treatment?
No. Mild astigmatism may not need correction if it causes no problems. An eye-care professional can judge what is appropriate. Treatment decisions.
Can contact lenses correct astigmatism?
Yes. Suitable lenses can be prescribed after assessment and fitting. Follow the care instructions because poor hygiene increases infection risk. Contact-lens options.
Related reading: Myopia, hyperopia and keratoconus.
This information is educational and cannot diagnose an eye condition or replace an individual assessment.
Sources and further reading
- National Eye Institute: Astigmatism
- NHS: Astigmatism
- Moorfields Eye Hospital: Astigmatism assessment and treatment
- NHS: Vision loss and urgent symptoms
General educational information prepared October 2026. Treatments described are general options; availability and suitability require an individual assessment.
