Astigmatism

Astigmatism is a common refractive eye condition that causes blurred or distorted vision at all distances. It frequently occurs alongside myopia (short-sightedness) or hyperopia (long-sightedness) in the same eye.

How Does Astigmatism Affect Vision?

For clear vision, the cornea and lens must focus light to a single precise point on the retina. In a normal eye, the cornea is smooth and evenly curved in all directions. With astigmatism, the cornea is irregularly shaped — curving more steeply in one direction than another, similar to the surface of a rugby ball rather than a soccer ball. This irregular curvature causes light to focus at two separate points on the retina instead of one, resulting in blurred, distorted, or slanted vision at all distances.

What Causes Astigmatism?

Astigmatism is often present from birth, but can also develop over time. Known causes and risk factors include:

• Irregular corneal shape from birth: Many people are simply born with a cornea that is not perfectly round.
• Eyelid pressure on the cornea: Persistent pressure from the eyelids can gradually alter corneal shape.
• Corneal scarring: Injury or infection can leave scars that distort the cornea's surface.
• Keratoconus: A progressive condition in which the cornea thins and bulges into a cone shape.
• Genetics: Astigmatism has a hereditary component — if one or both parents have astigmatism, their children have a greater risk of developing it too.

Common Symptoms of Astigmatism

Astigmatism can cause a range of visual and physical symptoms, including:

• Blurred or distorted vision at all distances
• Headaches, particularly after reading or screen use
• Eye fatigue and strain
• Squinting to try to see more clearly
• Eye discomfort or irritation
• Doubled or ghost images, especially at night
• Difficulty focusing on printed words or lines consistently

Astigmatism Treatment Options

An optometrist or ophthalmologist can diagnose astigmatism during a routine eye examination. Treatment depends on the degree of astigmatism, your age, occupation, and lifestyle. Options available in Australia include:

• Prescription glasses: The most common correction method. Specially shaped lenses compensate for the irregular corneal curvature and focus light correctly onto the retina.
• Toric contact lenses: Specifically designed for astigmatism, toric lenses have different powers in different meridians of the lens to correct the uneven curvature of the cornea. Many patients achieve better vision with toric lenses than with standard contact lenses.
• Laser eye surgery (LASIK/PRK): A surgical option that reshapes the cornea to correct the refractive error. Laser surgery is suitable for low to moderate astigmatism and eliminates the need for glasses or contact lenses.

Frequently Asked Questions About Astigmatism

Can astigmatism be corrected with regular contact lenses?

Standard spherical contact lenses are generally not suitable for correcting astigmatism. Toric contact lenses are specifically designed to address the irregular corneal shape associated with astigmatism and typically provide much better vision correction.

Is astigmatism the same as blurry vision?

Astigmatism causes blurry or distorted vision, but not all blurry vision is caused by astigmatism. Myopia, hyperopia, and other conditions can also cause blurred vision. An eye examination is the only way to accurately determine the cause.

Can astigmatism get worse over time?

Astigmatism can change over time, particularly during childhood and adolescence. Regular eye examinations are important to monitor any changes and keep your prescription up to date.

Can astigmatism occur with myopia or hyperopia?

Yes. Astigmatism very commonly occurs alongside myopia (short-sightedness) or hyperopia (long-sightedness) in the same eye. This is why many prescriptions include a correction for both a refractive error and astigmatism.