Myopia and astigmatism are both refractive errors of the eye and are two common vision problems. However, astigmatism and myopia affect vision differently. Astigmatism causes blurred vision at all distances, while myopia leads to blurry vision only at a distance. Additionally, there are other key differences between them, and understanding these distinctions is crucial for anyone who wears glasses or contact lenses.
What’s the Myopia & Astigmatism?
What is Refractive Error?
To understand myopia and astigmatism, it’s important to first grasp what a refractive error is. A refractive error occurs when parallel light rays pass through the eye’s refractive surfaces but are not properly focused on the retina, instead forming an image either in front of or behind it. This results in a blurred image. Refractive errors include hyperopia (farsightedness), myopia (nearsightedness), and astigmatism. As one of the most common eye problems, over 1.5 billion people worldwide have a refractive error, accounting for about 30% of the population.
What is Myopia?
Myopia, also known as nearsightedness, is a condition where you can see close objects clearly, but distant objects appear blurry. It occurs when the eyeball is too long or the cornea is too curved, causing light to focus in front of the retina instead of directly on it, leading to blurry vision when looking at distant objects. Myopia is most common among teenagers and is often caused by poor visual habits. Typically, myopia stabilizes between the ages of 25 and 35.
Causes of Myopia
Myopia is usually related to both genetic and environmental factors. If one or both parents have moderate to severe myopia, there’s a higher chance their children will develop it too. Additionally, excessive near work or prolonged screen time, such as reading, using computers, or mobile devices, can lead to myopia, especially in children.
Common Symptoms of Myopia
- Blurred vision when viewing distant objects
- Squinting to see distant objects
- Eye strain or headaches, especially after trying to focus on distant objects for extended periods
- Poor night vision (night blindness)
What is Astigmatism?
Astigmatism is another common refractive error, but unlike myopia, it causes blurred vision at all distances—near, far, and in between. Astigmatism occurs due to an irregularly shaped cornea or lens. Normally, the cornea is evenly curved, but in people with astigmatism, the cornea has more of an oval shape, like a football. This irregularity causes light to focus on multiple points in the eye, resulting in blurred or distorted vision. Mild astigmatism (less than -0.50) may not require correction, but higher degrees of astigmatism typically need treatment.
Causes of Astigmatism
Astigmatism is usually present at birth and can occur alongside other refractive errors such as myopia or hyperopia. While the exact cause is not always clear, genetics play a significant role. Eye injuries or surgeries that change the shape of the cornea can also lead to astigmatism.
Common Symptoms of Astigmatism
- Blurred or distorted vision at all distances
- Eye strain or discomfort after prolonged visual tasks
- Headaches
- Difficulty seeing at night or sensitivity to glare
What’s the Differences Between Myopia & Astigmatism?
Although both myopia and astigmatism are refractive errors that affect vision, they differ in several ways:
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Vision Problem
Myopia causes distant objects to appear blurry while close objects remain clear. Astigmatism causes blurred or distorted vision at all distances and can occur alongside myopia or hyperopia.
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Cause
Myopia is caused by an elongated eyeball or excessively curved cornea, which results in light focusing in front of the retina. Astigmatism is due to an irregularly shaped cornea or lens, which causes light to focus on multiple points within the eye.
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Symptoms
Myopia often manifests as difficulty seeing distant objects clearly, squinting, and eye strain. Astigmatism results in vision distortion at all distances, accompanied by eye discomfort and headaches.
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Developmental Age
Myopia usually develops during adolescence and stabilizes by the age of 25-35.Astigmatism can develop or worsen at any age.
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Treatment
Myopia can be corrected with standard lenses or surgical procedures. Astigmatism requires specially designed corrective lenses (such as cylindrical lenses or toric contact lenses) or surgery to reshape the cornea.
Can Myopia and Astigmatism Coexist?
Yes, myopia and astigmatism can coexist, and this is quite common. When both conditions are present, a person may experience blurry vision at all distances due to astigmatism, along with difficulty seeing distant objects due to myopia. In such cases, custom corrective lenses or surgery may be necessary to address both refractive errors.
Eye Health and Lifestyle
Both refractive errors can worsen over time, particularly in children and young people. To slow the progression of myopia, doctors may recommend reducing screen time, increasing outdoor activities, and adopting good eye care habits. For people with astigmatism, regular eye exams and wearing the correct prescription lenses can prevent symptoms from worsening.
