Astigmatism: Meaning, Causes, Symptoms, Diagnosis, and Treatment

If objects or people seem blurry or distorted even when you are not far away, you could be dealing with astigmatism. This is a common vision condition. Astigmatism isn’t something to worry about—it’s simply how your eye is shaped. 

It can impact your daily activities. With the right treatment, you can improve your vision and live life clearly. 

Meaning of Astigmatism

Astigmatism is a refractive error. It means that the shape of your eye prevents light from focussing correctly on the retina. Normally, the cornea or lens of the eye is evenly curved. This allows light to enter and focus at a single point. 

In individuals with astigmatism, the cornea or lens has an irregular shape, like a football rather than a basketball. This results in multiple focus points and blurry or distorted vision at various distances.

People with astigmatism may experience difficulty seeing clearly at night, headaches, or eye strain after long periods of focusing on tasks like reading or working on a computer. It’s a common condition that can be present from birth or develop later due to eye injuries or surgeries. 

Astigmatism can affect both children and adults and can occur in conjunction with myopia (nearsightedness) or hypermetropia (farsightedness).

The good news is that modern treatments are effective and accessible, helping millions of people correct their vision.

What are the causes of Astigmatism

Astigmatism is not caused by reading in dim light, sitting too close to the television, or poor posture while using digital devices. Primary astigmatism causes include the following:

• Genetics: Many people inherit astigmatism from their parents. If you have family members with astigmatism, you are more likely to have it, too.
• Eye Injuries or Surgery: Damage to the cornea or eye surgeries can change its shape, leading to astigmatism. For instance, cataract treatment in the form of surgery may sometimes cause or worsen astigmatism.
• Keratoconus: This condition where the cornea becomes progressively thinner and more cone-shaped over time, leading to severe astigmatism.
• Natural Changes with Age: As you age, changes in the shape of the eye’s lens can also contribute to the development of astigmatism.

Understanding these astigmatism causes can help you seek timely eye care and avoid confusion with other vision problems.

What are Astigmatism symptoms?

Astigmatism symptoms can vary from person to person, depending on the severity of the condition. In mild cases, individuals might not even notice the symptoms. Others may experience noticeable discomfort in everyday activities. 

Blurred or Distorted Vision: This is the most obvious symptom of astigmatism. Objects, both near and far, can appear out of focus, wavy, or stretched.

Eye Strain: Because the eyes are working harder to focus, you might experience discomfort or a tired sensation in the eyes after prolonged visual tasks like reading or using digital devices.

Headaches: Constantly correcting your focus can lead to frequent headaches, especially after activities that demand visual concentration.

Difficulty Seeing at Night: Night driving or low-light situations can be particularly challenging for individuals with astigmatism, as the eyes may struggle more to focus in these conditions.

Squinting: People with astigmatism often squint to try and bring objects into clearer focus, though this can only provide temporary relief.

If you are noticing these astigmatism symptoms, it’s important to get an astigmatism test. 

How Does Astigmatism Affect Vision?

Astigmatism affects vision by distorting how light is focused onto the retina, the light-sensitive layer at the back of the eye. This can make it difficult to see fine details, both up close and at a distance. Some people with astigmatism report that their vision is clearer when they squint, but this isn’t a sustainable solution. Additionally, because the eyes are constantly trying to compensate for the misfocus, people with astigmatism may experience eye strain, fatigue, or even headaches after prolonged periods of concentration.

Astigmatism can also affect night vision, making activities like driving more challenging. Street lights, headlights, and other bright lights may appear streaky or haloed, further complicating vision in low-light conditions. 

Types of Astigmatism

There are two main astigmatism types, depending on which part of the eye is affected. 

Each type affects how light is refracted and can cause varying vision distortion.

Corneal Astigmatism

Corneal astigmatism occurs when the cornea, the eye’s clear front surface, has an irregular curvature. Here, the cornea may be shaped more like an oval instead of round. This uneven curvature causes light to refract unevenly, leading to blurred or distorted vision. 

It is the most common form of astigmatism. This astigmatism type can be inherited or result from eye injuries. People with this condition often find their vision blurry at all distances. They are known to experience headaches and strain as their eyes work harder to focus.

Lenticular Astigmatism

Irregularities in the shape of the lens inside the eye cause lenticular astigmatism. Even if the cornea is perfectly shaped, the lens distorts the light entering the eye. While less common than corneal astigmatism, lenticular astigmatism can occur naturally or due to age-related changes in the lens. 

People with lenticular astigmatism might have difficulty seeing clearly up close and far away. This happens when their lens becomes less flexible over time.

Astigmatism Diagnosis and Test

Astigmatism can be easily diagnosed during a routine eye exam. Eye doctors use several astigmatism tests to measure the degree of astigmatism and determine the best course of treatment. 

1. Visual Acuity Test: This is the classic eye chart test. This astigmatism test helps assess how well you can see at different distances and is one of the basic tests used to detect refractive errors, including astigmatism.
   
   2. Keratometry: This astigmatism test measures the curvature of the cornea. A keratometer shines a light on the cornea and measures how it reflects. By analysing this reflection, doctors can identify the degree of corneal astigmatism.
   
   3. Corneal Topography: Corneal topography provides a 3D image of its shape and surface for a more detailed cornea map. This astigmatism test is particularly useful if irregular astigmatism or conditions like keratoconus are suspected.
   
   4. Refraction Test: In this astigmatism test, a series of lenses are placed in front of your eyes while you look at a chart. You’ll be asked which lens helps you see more clearly. This helps determine the exact prescription needed to correct your vision.
   
   5. Auto refractor: This device automatically measures how light is refracted in the eye, helping detect the presence and degree of astigmatism quickly.

How to treat Astigmatism

Treating astigmatism depends on the severity of the condition and your lifestyle needs. Fortunately, several effective ways exist to correct the blurred or distorted vision caused by astigmatism, allowing you to see clearly again.

Eyeglasses are the simplest and most common astigmatism treatment for people with mild to moderate astigmatism. Special lenses are designed to counterbalance the irregular curvature of the eye, helping light focus correctly on the retina. Eyeglasses can correct both corneal and lenticular astigmatism, and they’re an affordable, non-invasive option.

Toric contact lenses are specifically designed for people with astigmatism who prefer not to wear glasses. These lenses have different focusing powers in various parts of the lens, helping correct the refractive error. While contact lenses offer a wider field of view and are more cosmetically appealing, they require proper care to avoid infections or discomfort.

For a more permanent astigmatism treatment, procedures like LASIK or PRK reshape the cornea, correcting the curvature and improving vision. These surgeries are popular among people with moderate to severe astigmatism who want to reduce their dependence on glasses or contact lenses. 

Orthokeratology (Ortho-K), an advanced astigmatism treatment, involves wearing specially designed rigid contact lenses overnight to reshape the cornea temporarily. The lenses correct astigmatism while you sleep, providing clear vision during the day without needing glasses or contacts. However, the effects are temporary, and the lenses must be worn regularly to maintain results.

Advanced eye care units like Nethradhama Super Specialty Eye Hospital offer state-of-the-art treatments for astigmatism, providing tailored solutions based on individual needs. 

Conclusion

Astigmatism may cause blurry vision and discomfort, but it’s a highly treatable condition. There’s a solution for everyone, with options ranging from eyeglasses and contact lenses to advanced laser surgeries. Regular eye exams are crucial for early detection, especially if you’re experiencing symptoms like eye strain or difficulty seeing at night.

Whether you choose a simple fix like glasses or a more permanent option like LASIK, managing astigmatism is easier than ever. For specialised care, trusted institutions like Nethradhama Super Specialty Eye Hospital offer comprehensive diagnosis and treatment options to help you see clearly and comfortably.