How can Laser Vision Correction help?

What is Astigmatism?

Astigmatism is a common and usually treatable vision condition that causes blurred or distorted vision at all distances. It occurs when the cornea (the clear front surface of the eye) or the lens inside the eye has an irregular shape.

In a normal eye, the cornea is shaped like a perfectly round dome, similar to a basketball, allowing light to focus sharply on the retina at the back of the eye.

In astigmatism, the cornea or lens is shaped more like an oval or a football, with one curve steeper than the other. This uneven curvature prevents light from focusing evenly on the retina, resulting in blurred, stretched, or shadowed vision.

Astigmatism can occur on its own or in combination with myopia (near-sightedness) or hyperopia (far-sightedness). It is not a disease but a refractive error, meaning it affects how the eye bends, or refracts, light.

Types of Astigmatism

There are two main types of astigmatism, based on where the irregular curvature occurs:

• Corneal Astigmatism: Caused by an irregular shape of the cornea. This is the most common form.
• Lenticular Astigmatism: Caused by an irregularity in the shape of the lens inside the eye.

For those that seek more technical detail, Astigmatism is also classified by the axis or orientation of the irregular curvature:

• With-the-rule astigmatism: The vertical meridian is steeper.
• Against-the-rule astigmatism: The horizontal meridian is steeper.
• Oblique astigmatism: The steepest curvature lies at an angle between the vertical and horizontal axes.

Causes of Astigmatism

The exact cause of astigmatism is not fully understood, but several factors can contribute as detailed below.

• Genetics: Astigmatism often runs in families.
• Developmental changes: It can be present at birth or develop over time.
• Injury or surgery: Trauma or surgical procedures affecting the cornea can cause scarring or shape changes that lead to astigmatism.
• Eye conditions: Diseases such as keratoconus (a progressive thinning of the cornea) can result in irregular astigmatism.

Symptoms of Astigmatism

People with astigmatism may experience the below impacts to their vision.

• Blurred or distorted vision at any distance
• Eyestrain causing discomfort
• Headaches
• Difficulty seeing at night
• Squinting

These symptoms may be mild in cases of low astigmatism but become more noticeable as the degree of the astigmatism increases.

Diagnosing Astigmatism

Astigmatism is routinely and easily diagnosed through a comprehensive eye exam that may include some or all of the below tests.

• Visual acuity testing – reading letters on a chart
• Keratometry – measuring the curvature of the cornea
• Corneal topography – creating a detailed map of the cornea’s surface
• Refraction tests – to determine the exact prescription needed to correct vision

Traditional Correction Methods

Mild to moderate astigmatism can be effectively corrected with the below ophthalmic treatments.

• Spectacles or glasses: Special cylindrical lenses correct the uneven curvature
• Contact lenses: Toric lenses are designed specifically to correct astigmatism
• Rigid gas permeable or scleral lenses: For more severe or irregular astigmatism, especially in cases like keratoconus.

However, many people seek a permanent solution through the use of Laser Vision Correction technology.

Laser Vision Correction for Astigmatism

Laser Vision Correction can reshape the cornea to correct the irregular curvature that causes astigmatism. The most common types of Laser Vision Correction include the below, all of which are available at Adelaide Eye & Laser Centre and your eye doctor will be able to advise which is best suited to you and your eyes, to achieve your visual goals.

LASIK is effective for mild to moderate astigmatism and is the most widely performed laser eye procedure and involves:

• Creating a thin flap on the surface of the cornea
• Using an excimer laser to reshape the underlying corneal tissue
• Replacing the flap, which heals naturally

How LASIK helps astigmatism:

• The laser is guided by a detailed map of the cornea (topography)
• It selectively removes microscopic layers of tissue to smooth and regularise the corneal surface
• The new shape enables light to focus properly on the retina, correcting astigmatism along with other refractive errors like myopia or hyperopia.
• Offers fast recovery meaning most patients see clearly within 24-48 hours.

SMILE is effective for mild to moderate astigmatism and is a newer procedure where:

• A femtosecond laser creates a small lens-shaped piece of tissue (lenticule) inside the cornea
• The lenticule is removed through a tiny incision, reshaping the cornea

SMILE offers the advantage of creating less disruption to the corneal surface with a lower risk of dry eye symptoms and also offers a fast recovery.

PRK is a surface ablation procedure where:

• The outer layer of the cornea (epithelium) is removed
• The excimer laser reshapes the corneal surface directly
• The epithelium regrows over several days

PRK is used in patients with thin corneas, dry eyes, or certain lifestyle needs (e.g.: that play contact sports). It provides the same visual outcomes as LASIK, but with a longer recovery time.

Your Suitability for Laser Vision Correction

With advances in modern technology, more people are candidates for Laser Vision Correction. At Adelaide Eye & Laser Centre, suitability is determined at a complementary pre-procedure assessment where each patient undergoes a number of tests with our ophthalmic clinicians first, and where you will then meet you eye doctor who will discuss your results and advise your suitability and your best option.

Conclusion

Astigmatism is a common refractive error that distorts vision due to an irregularly shaped cornea or natural lens. While glasses and contact lenses offer effective correction, Laser Vision Correction can provide a permanent, precise solution for many people to successfully correct their astigmatism and reduce their dependence on glasses and contact lenses providing lifestyle convenience.

Would you like to know more?

Adelaide Eye & Laser Centre was the first in South Australia to offer Laser Vision Correction and remains one of its most experienced. With expertise and skill in the treatment of all refractive errors including astigmatism. It offers a complete suite of all laser vision correction technologies including SMILE® Pro, LASIK and PRK.

If you would like a referral to the care of one of our laser vision specialists or have any questions, please do not hesitate to contact a member of our friendly team on 08 8274 7000 or by filling out the contact form here.