Astigmatism

Most astigmatism is mild and gradual. Common signs include:

• Blurry or stretched vision both up close and far away — letters can look like they have a shadow or ghost.
• Double or ghost images in one eye.
• Squinting or tilting the head to see clearly.
• Eye strain and headaches after reading or screen time.
• Trouble seeing at night — lights look streaky, starry, or have halos.
• Children sitting close, squinting, or tilting their head, or doing worse on classroom work that needs sharp vision.

Children with moderate or high astigmatism may not say anything is wrong because the blurry view is all they know. A first full eye exam between ages 3 and 5 catches most cases before they cause a lazy eye (amblyopia) ⁶.

When astigmatism is changing fast:

• If your glasses prescription is jumping every year — especially the cylinder (astigmatism) number — ask for a corneal topography map.
• Fast-changing astigmatism with new halos, starbursts at night, or trouble seeing even with new glasses can be an early sign of keratoconus, especially in teens and young adults who rub their eyes or have allergies. A corneal topography test can separate regular from irregular astigmatism ⁸.

Astigmatism happens when the cornea (the clear front of the eye) or the lens inside the eye is not shaped like a round ball. Instead, it is steeper in one direction than the other, like an American football. Light entering the eye splits into two focal points, so the image on the retina is blurry or stretched ².

There are two main types:

• Regular astigmatism — the steep and flat directions are 90 degrees apart. Most astigmatism is regular and is fixed with glasses or toric contact lenses.
• Irregular astigmatism — the corneal surface is uneven or warped. Glasses do not give sharp vision. Causes include keratoconus, corneal scarring from infection or injury, or past eye surgery. These eyes usually need rigid, hybrid, or scleral contact lenses, or a corneal procedure ³.

Things that can cause or raise the risk of astigmatism:

• Genes. Astigmatism runs in families. A child with one or both parents who have astigmatism is more likely to have it too.
• Age. The shape of the cornea slowly changes through life. Rates of astigmatism climb above 50% in people over 70 ¹.
• Keratoconus and other corneal diseases. Conditions that thin or warp the cornea cause irregular astigmatism.
• Eye rubbing and eye allergies. Hard, repeated rubbing — often driven by allergies, eczema, or asthma — has been linked to keratoconus, which causes fast-changing astigmatism.
• Eye injury or surgery. A scar on the cornea or a healed cataract or transplant wound can leave behind regular or irregular astigmatism.
• Contact lens warpage. Years of poorly-fitted or overworn rigid contact lenses can change corneal shape and cause astigmatism that may improve when the lenses are taken out.
• A heavy upper eyelid (ptosis) or a lid bump (chalazion). Pressure from the lid on the cornea can shift its shape.

Most astigmatism is easy to correct. The right choice depends on how much astigmatism you have, whether it is regular or irregular, your age, and what you want to do day to day ².

Glasses

• Simple, safe, and work for almost all regular astigmatism.
• The prescription has a cylinder number (the amount of astigmatism) and an axis number (the direction of the steep meridian).
• Children with moderate or high astigmatism should wear glasses full-time to prevent lazy eye (amblyopia).

Contact lenses

• Toric soft contact lenses — soft contacts shaped to correct regular astigmatism. Good for sport, school, and most everyday activities.
• Rigid gas-permeable (RGP) contact lenses — small hard lenses that sit on the cornea. They smooth out irregular astigmatism and are often the best vision option for keratoconus or post-surgery corneas.
• Hybrid lenses — rigid center with a soft outer skirt for comfort.
• Scleral contact lenses — large rigid lenses that vault over the cornea and rest on the white of the eye. Often the best comfort and vision for advanced irregular astigmatism.
• Orthokeratology ("ortho-K") — rigid lenses worn overnight that gently reshape the cornea so the wearer can see during the day without lenses. Best for mild-to-moderate astigmatism with myopia.

Laser eye surgery (for stable adult astigmatism)

• LASIK, PRK, and SMILE all reshape the cornea with a laser to correct regular astigmatism along with nearsightedness or farsightedness. Most candidates see well without glasses in the weeks after surgery. A large review of LASIK studies from 2016-2023 found high rates of 20/20 vision and few serious complications ⁷.
• One study of LASIK for mixed astigmatism found that more than 70% of eyes had 20/20 vision or better at 3 and 12 months after surgery ¹⁰.
• Best for adults whose prescription has been stable for at least a year and whose corneas pass screening. Standard LASIK is not safe for eyes with keratoconus or suspected keratoconus.

Astigmatism correction during cataract surgery

• Toric intraocular lens (toric IOL) — a special replacement lens placed inside the eye during cataract surgery that corrects astigmatism at the same time. A systematic review and meta-analysis found toric IOLs give better uncorrected distance vision and more spectacle independence than standard non-toric lenses ⁴.
• Limbal relaxing incisions (LRI) — tiny cuts at the edge of the cornea made during cataract surgery to flatten a small amount of astigmatism.
• A typical cost for a toric IOL is roughly $1,500-$3,000 per eye on top of the cataract surgery fee, though insurance coverage varies. Ask the surgery center for a written breakdown before scheduling.

For irregular astigmatism from corneal disease

• The first goal is to stop the underlying disease — for example, corneal cross-linking to stop keratoconus from getting worse, or treating allergies and stopping eye rubbing.
• Specialty contact lenses (rigid, hybrid, or scleral) give the sharpest vision in most cases.
• A small number of eyes need intracorneal ring segments or a corneal transplant for the best long-term vision.

Most people with astigmatism see well for a lifetime with the right glasses or contact lenses. A few habits help:

• Get a full eye exam every 1-2 years (yearly for kids, anyone with a fast-changing prescription, or anyone with high astigmatism).
• Wear up-to-date glasses or contacts. An old prescription causes headaches, eye strain, and blurry distance.
• Treat eye allergies and dry eye so your eyes do not itch — and do not rub your eyes hard. Repeated hard rubbing can lead to keratoconus, which causes irregular astigmatism that is much harder to fix.
• Take screen breaks. The 20-20-20 rule (every 20 minutes look about 20 feet away for 20 seconds) eases eye strain.
• Practice good contact lens hygiene. Always wash your hands. Never sleep in soft lenses unless approved. Replace lenses on schedule. Never use tap water on contacts.
• Have your child's eyes checked by age 3-5. Children with moderate or high astigmatism need glasses full-time to prevent a lazy eye ⁶.
• If you are thinking about laser eye surgery, ask the surgeon to share corneal topography and tell them about any family history of keratoconus.