Ask the Expert: What Causes Astigmatism to Worsen​?

Astigmatism is a common eye condition caused by an irregularly shaped cornea or lens, leading to blurred or distorted vision at all distances. While many people have stable astigmatism, some may notice worsening and wonder, whether an astigmatism can get worse over time and the short answer is: yes, it can. And this can happen for several reasons. Our experts will unpick these reasons, highlight what signs to look out for, and when it’s time to seek professional help.

How Does Astigmatism Affect Your Eyesight?

Astigmatism is caused by the cornea (the clear front surface of the eye) or lens having an irregular shape. We would like it to be perfectly round like a football, but instead it’s more like a rugby ball, and this is what leads to distorted or blurred vision.

Common symptoms of astigmatism include:

• Increased blurriness or distortion of vision
• Frequent changes in glasses or contact lens prescriptions
• Greater difficulty seeing at night
• More frequent headaches or eye strain

Despite these symptoms, many people live comfortably with mild astigmatism. It’s a common eye condition and doesn’t usually interfere with daily life. However, if your symptoms start to change or become worse, it’s worth exploring why that might be happening. Find out more about astigmatism to learn more about it and how it’s diagnosed.

What Causes Astigmatism to Worsen?

No one thing can cause astigmatism to worsen. Lifestyle factors, changes in health and eye conditions can all affect a change to your astigmatism.

• Natural ageing, which changes the shape and flexibility of the eye’s lens and cornea
• Eye injuries or surgeries that alter corneal shape
• Progressive eye conditions like keratoconus, which thins and bulges the cornea
• Incorrect or outdated vision correction, including improper contact lens use
• Genetic predisposition and family history

Genetic predisposition

Astigmatism has a strong genetic component. Children with one or both parents having astigmatism are more likely to develop it themselves, and genetic factors influence corneal shape and eye development. This inherited tendency can contribute to the onset and progression of astigmatism over time.

Eye Injuries

Trauma or surgical procedures (like cataract surgery or corneal transplants) can alter the cornea’s smooth, regular shape. Scarring, swelling, or changes in corneal curvature from these events can induce or worsen irregular astigmatism by disrupting the normal corneal surface.

Ageing

As we age, the cornea and lens of the eye gradually change shape and lose flexibility. The cornea may flatten or shift its curvature, especially in the vertical meridian, causing a shift from “with-the-rule” to “against-the-rule” astigmatism, which tends to increase overall astigmatism magnitude. Changes in eyelid pressure and muscle tone around the eye also affect corneal shape, contributing to these shifts.

Can Keratoconus Cause Astigmatism to Worsen?

Keratoconus is a disease where the cornea progressively thins and bulges outward into a cone shape. This irregular protrusion causes highly asymmetrical, irregular astigmatism that worsens over time as the cornea weakens and its collagen structure breaks down6. The condition typically starts in adolescence or early adulthood and can severely distort vision if untreated.

What Causes Astigmatism to Get Worse in One Eye?

Astigmatism will not necessarily appear the same in both eyes, and astigmatism can worsen in just one eye. This could be caused by:

• An injury or infection affecting one eye
• Asymmetrical corneal shape changes with age
• Localised conditions such as keratoconus
• Previous surgeries (e.g., LASIK in one eye only)

In summary, ageing and structural changes to the cornea or lens naturally alter eye shape, injuries or surgeries physically disrupt corneal smoothness, keratoconus causes progressive corneal deformation, improper correction affects symptom perception, and genetics influence baseline risk and progression of astigmatism. Regular eye exams help monitor these changes and guide timely treatment.

Treatment Options for Astigmatism

Fortunately, there are many effective treatments for astigmatism, depending on its severity. These can include:

• Prescription glasses and/or contact lenses
• Toric contact lenses – designed specifically for astigmatism
• Orthokeratology – overnight lenses that reshape the cornea
• Laser eye surgery, such as LASIK or LASEK
• Lens replacement surgery for more complex cases

For expert guidance on your options, explore  whether laser eye surgery can fix astigmatism to understand more.

Discuss Laser Eye Surgery Requirements with Our Experts

If you’re seeking vision correction treatment, like laser eye surgery, contact us today to book a consultation with one of our expert surgeons and start your journey to clearer, more comfortable vision.