Astigmatism, the vision disorder that affects nearly half of us

 

Is Your Eye Shaped Like a Rugby Ball?

Have you ever left the ophthalmologist's office with this strange image in your head? The image that your eye looks more like a rugby ball than a round marble. Or perhaps, more simply, have you noticed that your vision is becoming increasingly blurry, and that focusing on an object or text requires constant effort? If these situations resonate with you, you're not alone. Far from it. You're probably one of the 40% of the world's population living with astigmatism. It's a word that may seem complicated, but the phenomenon is very common.

What exactly is astigmatism?

To put it simply, imagine your eye as a camera. Light enters through the front surface, called the cornea, and the image is formed on the "film" at the back of the eye, the retina. For the photo to be sharp, all parts of the apparatus (the cornea, the lens, the retina) must have a specific shape and size. When this isn't the case, the image is blurry. This is called a "refractive error." Astigmatism is precisely one of these defects, which occurs when the surface of the eye is not perfectly smooth and round. There are two main types: Regular astigmatism: This is the most common. The cornea is oval in shape, a bit like an egg or a rugby ball. We don't always know why this happens, but it often runs in families and is genetic in origin. Irregular astigmatism: Much rarer. It appears when the cornea is damaged (a scar, a small growth) or when it becomes unevenly deformed. This is the case with diseases like keratoconus, where the cornea weakens and takes on the shape of a cone.

Symptoms that should alert you

With mild astigmatism, it's possible to go unnoticed. But when it becomes more severe, vision deteriorates, and certain signs are unmistakable. The main symptoms are: Blurry or distorted vision, both near and far. Frequent headaches. Eye fatigue, especially after staring at something for a long time, such as a computer screen or a book. Astigmatism is often accompanied by myopia (difficulty seeing far away) or hyperopia (difficulty seeing up close). This can make the diagnosis a little confusing at first, but a good eye exam quickly clarifies things.

A discovery that's nothing new

You might think this is a modern condition, but it's not! As early as 1727, the great scientist Isaac Newton described how an irregular surface could disrupt the path of light. A little later, in 1800, another scientist, Thomas Young, himself astigmatism, described in great detail how this defect affected his own vision. But the real breakthrough comes from an astronomer, Sir George Airy. In 1825, also astigmatism, he noticed that he saw better by tilting his glasses. It was he who had the brilliant idea of using "cylindrical" lenses to correct this. These lenses are still used today! The name “astigmatism” came much later, in 1846. It comes from the Greek “a-” (without) and “stigma” (point), which literally means “without point”, because light does not focus on a single, clear point on the retina.

How to detect it and what are the solutions?

Astigmatism is usually detected during a standard eye exam by an ophthalmologist or optician. For more complex cases of irregular astigmatism, a test called corneal topography creates a 3D map of the cornea to reveal all its defects. Fortunately, there are several solutions to regain clear vision: Glasses or contact lenses: This is the simplest and most common solution. Cylindrical lenses compensate for the curvature of the cornea. Laser surgery: An option for permanently correcting the defect. Orthokeratology (Ortho-K): This involves wearing special rigid lenses overnight. They temporarily reshape the cornea, allowing you to see clearly all day long without glasses. It's a pretty clever system. For irregular astigmatism, rigid lenses are often the best solution. As a last resort, a corneal transplant may be necessary.

Conclusion: What about our children and grandchildren?

This is a question many grandparents ask themselves. Should we be worried if astigmatism is detected in a child? The answer is no, there's no need to panic. Astigmatism itself isn't dangerous. However, if left uncorrected, severe astigmatism can hinder a child's learning, both at school and in sports. It can even lead to other problems, such as strabismus (a squinting eye) or amblyopia, also known as "lazy eye." But don't worry. The solution is simple: regular eye checkups for children (and adults too, for that matter!). This allows the problem to be detected early and easily corrected. A quick visit to the ophthalmologist can be life-changing. According to the source: theconversation.com