If you’ve ever paid a visit to the optometrist and been told your eyes are shaped like a football, you could be one of the people unknowingly living with this eye ‘error.’

An astigmatism is a common refractive error of the eye, where one or sometimes more of the eye’s surfaces aren’t perfectly smooth or round, and is put into two categories – regular and irregular.

As it turns out, around 40% of the population are thought to have this exact differentiation on their eye, and it can come with a few unwanted symptoms.

How to manage astigmatism

According to experts at the Centre for Eye Research Australia and an honorary fellow at the University of Melbourne, mild astigmatism may not cause any problems with your vision.

Although, with increasing levels of astigmatism, you may start to experience reduced vision, eye strain, and fatigue. There is an option to have astigmatism correction for a clearer vision, which will help compensate for the difference in curvatures of the cornea and work to allow any light entering the eye to be focused more clearly on the retina.

An option for doing this is through the use of cylindrical lenses, which can be prescribed as either glasses or contact lenses—or, as a more permanent solution, with laser eye surgery. The research scientists explained in their report: “Orthokeratology can also be used.

“This involves wearing specialised hard contact lenses overnight. These hard contact lenses temporarily reshape the cornea, allowing the wearer to be glasses-free during the day.

“To manage irregular astigmatism, it is important to treat the underlying condition causing astigmatism as well. But often, hard contact lenses are needed for clear vision during the day, as they can sit on the surface of the eye to compensate for local uneven patches in a way that glasses or soft contact lenses cannot.”

Regular vs. Irregular Astigmatism

The most common form is regular astigmatism, which tends to come from any change in the shape of your cornea, the clear outer layer at the front of your eye. Unlike others, it appears in a more oval shape, similar to a football or even an egg and it is yet to be understood exactly why but it is thought to be down to basic genetics.

A rarer form is irregular astigmatism, which occurs when a part of the cornea is no longer smooth, usually caused by scarring or a growth on the cornea, or even if its shape has taken a new uneven form. Eye conditions such as keratoconus, which sees the cornea gradually weaken and transform into a cone-like shape, tend to cause irregular astigmatism.

When a cornea is no longer smooth or round, when light enters the eye, it will scatter across the retina, often causing distorted vision. Along with it comes a lack of sensitivity to high contrasts, shadows, or even double vision and an increased sensitivity to bright lights.

The cause of astigmatism

A perfect analogy to explain how our eyes work is by comparing it to the inner workings of a camera, capturing light through the front surface, which is the cornea, and focusing in on the ‘film,’ which sits at the back, as the retina. The eyeball and all of its layers have to meet a specific size and shape quota in order to get the clearest of pictures, and without it, the vision can be blurred or out-of-focus, like a camera. 

This information is not new to us; in fact, as far back as 1727, Sir Isaac Newton was the first to explain the basic physics of how an irregular surface has the ability to affect the focus of light as it passes through. It wasn’t long before Thomas Young, in 1800, confirmed he himself had astigmatism and was able to describe exactly how it affected his vision.