Astigmatism is a common focusing error in which the cornea or, less often, the lens is curved more steeply in one direction than the other, more like a rugby ball than a football. Light is focused at two points instead of one, blurring vision at all distances. It usually occurs together with short sight or long sight.
Small amounts are normal and need no treatment. Larger amounts are corrected with glasses, toric contact lenses, laser eye surgery or a toric lens implant. Astigmatism that keeps increasing, particularly in a teenager or young adult, should be checked for keratoconus, which is managed differently.
Symptoms
- Blurred or distorted vision for both near and distance
- Eye strain and tired eyes after reading or screen use
- Headaches, especially around the brow
- Squinting or tilting the head to see clearly
- Glare, haloes or streaks around lights and difficulty driving at night
- Letters that look doubled or shadowed
- In young children, no complaints, only a failed vision screening
Causes and risk factors
Most astigmatism is present from early life and relates to the inherited shape of the cornea; it often changes little in adulthood. It tends to shift in axis with age. It can also be acquired: from keratoconus and other corneal thinning disorders, corneal scars after injury or infection, a pterygium pulling on the cornea, eyelid lumps pressing on the eye, or after eye surgery such as cataract surgery or corneal transplantation. Irregular astigmatism, in which the surface is unevenly distorted, cannot be fully corrected with ordinary glasses. Reading in poor light or sitting close to screens does not cause it.
How it is diagnosed
- Refraction: An optometrist or ophthalmologist measures the power and axis of the astigmatism, with drops to relax focusing in children.
- Keratometry and corneal topography: Map the curvature of the front of the cornea, distinguish regular from irregular astigmatism and detect early keratoconus.
- Corneal tomography: Scheimpflug or OCT-based scans measure the back surface and thickness of the cornea. Mandatory before any laser surgery.
- Full eye examination: Checks the lens, retina and eye pressure, and looks for cataract as a cause of changing prescription.
Treatment options
- Glasses: Cylindrical lenses correct regular astigmatism. New or changed prescriptions can make floors seem tilted for a week or two.
- Toric contact lenses: Soft toric lenses for regular astigmatism, and rigid gas permeable or scleral lenses for irregular astigmatism and keratoconus.
- Laser vision correction: LASIK, PRK or lenticule extraction reshape the cornea, generally treating up to about 5 to 6 dioptres of astigmatism in eyes with healthy corneas and stable prescriptions.
- Toric implantable contact lens: A lens placed in front of the natural lens, for high prescriptions or corneas too thin for laser.
- Toric intraocular lens at cataract or lens surgery: Corrects astigmatism at the same time as removing a cataract. Rotation of the lens after surgery occasionally requires repositioning.
- Corneal cross-linking: Stabilises progressive keratoconus. It stops the astigmatism worsening but does not remove it.
When it is urgent
Astigmatism itself is never an emergency. Seek urgent local eye care for sudden loss or distortion of vision, a painful red eye, especially in a contact lens wearer, or flashes and a shower of new floaters. After laser or lens surgery, increasing pain, redness or falling vision need the operating team or a local eye casualty the same day.
Travelling to Türkiye for treatment
Laser vision correction and toric lens surgery are planned procedures that suit a short visit: assessment and treatment of both eyes usually take 3 to 5 days for laser, and about a week for lens implants, with checks before you fly. Stop soft contact lenses 1 to 2 weeks and rigid lenses 3 to 4 weeks before the measurements. Arrange follow-up at 1 month and 3 months with an eye specialist at home. Children's astigmatism and progressive keratoconus need regular monitoring locally.
Send your reports, scans and a short history and a Clinic-Y coordinator replies within 24 hours with suitable teams and written, all-inclusive proposals side by side. Reviewing your case is free.
Frequently Asked Questions
Does astigmatism get worse over time?
Usually it changes slowly, if at all. A prescription that keeps rising in the teens or twenties should prompt corneal topography to look for keratoconus.
Can laser surgery correct it completely?
It corrects most regular astigmatism well, though a small residual amount is common with high prescriptions. An enhancement is sometimes needed. Irregular astigmatism is not suitable for standard laser treatment.
Do I need a toric lens for my cataract operation?
If you have more than about 1 dioptre of corneal astigmatism and want good distance vision without glasses, a toric lens is worth discussing. Otherwise glasses will correct it afterwards.
My child has astigmatism. Must they wear glasses all the time?
If the amount is significant, yes, because uncorrected astigmatism in early childhood can lead to amblyopia. Small amounts are just monitored.