Myopia, hyperopia, astigmatism, and presbyopia: what exactly causes them?

Phyathai 3

2 Min

Th 18/03/2021

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Myopia, hyperopia, astigmatism, and presbyopia: what exactly causes them?

The most common and significant vision problem is blurry vision caused by corneal abnormalities, whether it is nearsightedness, farsightedness, astigmatism, or presbyopia in the elderly. Today, we will explain the symptoms of blurry vision caused by these conditions and the causes behind each in the eye.

Myopia (Nearsightedness)

This condition occurs when the cornea is too curved or the eyeball is too long, causing light to refract and focus in front of the retina instead of on it, resulting in a blurry image. People with myopia see well at close distances but have blurry vision at far distances, often needing to squint or strain their eyes.

Hyperopia (Farsightedness)

This condition occurs when the cornea is too flat or the eyeball is too short, causing light to refract and focus behind the retina, resulting in a blurry image. People with hyperopia see better at far distances than at close distances and may experience headaches or eye strain, especially when looking at objects up close.

Astigmatism

This condition occurs when the cornea has uneven curvature in different axes, causing two focal points that do not merge into a single image. One focal point is either in front of or behind the retina. People with astigmatism experience blurry vision at both near and far distances.

Presbyopia

This normally occurs in people aged 40 and above, with farsightedness gradually increasing with age. It is caused by weakening of the ciliary muscles around the lens, reducing the lens’s ability to bulge and focus on close objects. This is a natural age-related vision change that can happen to everyone. Symptoms worsen with age and can occur even in people who have had good vision all their lives or coexist with myopia, hyperopia, or astigmatism.

 

Regardless of whether you have eye, vision, or sight problems, you should promptly consult an ophthalmologist for accurate diagnosis and treatment before the condition worsens and becomes difficult to treat.


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