Astigmatic Keratotomy (AK) Eye Surgery

Medically Reviewed on 12/13/2022
Astigmatic Keratotomy
Although a reduction in astigmatism is often observed immediately after astigmatic keratotomy, it might take a few weeks before the results stabilize.

Astigmatic keratotomy (AK) is a safe and effective eye surgery used to correct astigmatism, an imperfection in the curvature of the eye's cornea or lens.

AK has a better success rate of obtaining normal vision in people with mild eyeglasses or contact lens prescriptions. People with severe astigmatism may require glasses or contact lenses even after AK.

What is astigmatic keratotomy eye surgery?

Astigmatic keratotomy (AK; also known as limbal relaxing incision) is an eye surgery that corrects astigmatism.

The normal curvature of the cornea is spherical (resembling a basketball), and astigmatism causes a change in the corneal curvature making it football- or oval-shaped, leading to misshaping of the curvature (one end being flat and the other steep).

AK is a type of corneal relaxing incision surgery that helps correct astigmatism by making one or two incisions at the steepest part of the cornea, relaxing it, and turning it into a more rounded shape.

Who is a candidate for astigmatic keratotomy eye surgery?

Astigmatic keratotomy (AK) may be ideal for people who have:

  • A quest to reduce their dependence on glasses or contact lenses
  • Mild to moderate astigmatism
    • Congenital astigmatism
    • Residual corneal astigmatism
    • Post-traumatic astigmatism
    • Astigmatism after corneal transplantation
  • Stable glasses or lens prescription for at least a year
  • Good general health
  • No other eye problems affecting recovery, such as severe dry eyes

In some cases, AK is performed on people who have residual astigmatism after previously undergoing any of the following:

  • Cataract surgery
  • Corneal transplants (penetrating keratoplasty or partial thickness)
  • Radial keratotomy

How is astigmatic keratotomy eye surgery done?


  • A doctor evaluates the patient’s thorough medical history and tests their eyes to measure corneal thickness, refraction, corneal mapping, eye pressure, and pupil dilation.
  • On the day of surgery, the patient is advised to eat a light meal and take all of the prescribed medications.
  • The patient must avoid wearing eye makeup or bulky accessories in the hair that may interfere with the positioning of the head under the laser.


  • Under topical (anesthetic eye drops) anesthesia, the doctor makes one or two incisions using a diamond surgical blade at the steepest part or parallel to the edge of the cornea.
  • These incisions help change the football shape of the cornea into a rounded shape for better vision.
  • The entire procedure usually lasts not more than 10 minutes for both eyes. 


  • The eye may remain sensitive to light for a few hours after the surgery or give a feeling of a foreign object. 
  • It is an outpatient procedure, which means the patient can go home shortly after the surgery.
  • The patient may be asked to use eye shields/patch to protect the eyes.
  • The doctor may prescribe antibiotic eye drops to prevent infection and inflammation and reduce irritation.
  • Although a reduction in astigmatism is often observed immediately after surgery, it might take a few weeks before the stabilization of results.


The colored part of the eye that helps regulate the amount of light that enters is called the: See Answer

What are the pros of astigmatic keratotomy eye surgery?

Some of the pros of astigmatic keratotomy eye surgery include:

  • A safe, effective, and quick way to correct astigmatism
  • It can be used in conjunction with other vision-correction procedures
  • A good option for older patients
  • Corrects higher levels of astigmatism
  • More affordable than laser refractive surgery

What are the cons of astigmatic keratotomy eye surgery?

A few cons of astigmatic keratotomy eye surgery are as follows:

  • Mild discomfort (usually lasting one to two days)
  • Fluctuating vision (for the first few months post-surgery)
  • Infection
  • Red or itchy eyes
  • Weaker corneal structure, making it more vulnerable to rupture (if injured)
  • Higher risk of overcorrection
  • Extended healing time is around three months
  • The outcome is irreversible
  • Glare/halos/starburst around lights (sometimes permanent)
  • Light sensitivity

What are the alternative treatment options to correct astigmatism?

Although glasses and contacts are the most common treatment options for astigmatism, other procedures that may help correct astigmatism include:

  • Laser in-situ keratomileusis: A laser eye surgery that corrects refractive errors, including astigmatism, myopia, and hyperopia
  • Photorefractive keratectomy: Another type of laser refractive surgery done in people with thinner corneas or high prescriptions
  • Refractive lens exchange: Astigmatism correcting procedure that removes the natural lens in the eye and replaces it with an intraocular lens (IOL) implant 
  • Cataract surgery: Recommended for older patients who have cataracts along with astigmatism
  • Phakic IOL implant surgery: A procedure that involves placing an implant in front of the iris (anterior chamber) or behind the iris (posterior chamber)

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Medically Reviewed on 12/13/2022
Image Source: Getty image

Limbal Relaxing Incisions and Astigmatic Keratotomy Eye Surgery. WebMD:

Astigmatic Keratotomy (AK). Vision Center:

Astigmatic Keratotomy: Eye Surgery for Astigmatism Correction.

Femtosecond Laser-Assisted Astigmatic Keratotomy: A Review. NIH: