What is astigmatism?
Disease description:
Recently, my vision has become slightly blurry, especially when looking at lights, where I experience double vision. After an examination, I was told that I have astigmatism. What exactly is astigmatism? Can astigmatism cause visual distortion and decreased vision?
Doctor's answer (1)
Dr. Wang Shuai
Astigmatism is a common refractive error of the eye, primarily caused by irregularities in the shape of the cornea or lens. This irregularity prevents light entering the eye from focusing accurately on the retina, thereby affecting visual clarity.
Under normal circumstances, the front surface of the eye and the internal lens should function like a perfectly spherical mirror, evenly focusing light onto the retina. However, in individuals with astigmatism, these structures may take on an oval or橄榄-shaped form, causing light to focus at different points depending on its direction. Some light rays may focus in front of the retina, while others may focus behind it, or multiple focal points might form at different locations on the retina, resulting in blurred vision, double vision, or distorted vision.
The causes of astigmatism can be broadly categorized into two groups:
1. Congenital factors: These include heredity and inadequate development at birth. Heredity refers to an increased likelihood of astigmatism in children if one or both parents have it. Inadequate development at birth may be related to poor corneal development or incomplete development of intraocular regulatory tissues.
2. Acquired factors: These include eye diseases, eye surgeries or injuries, excessive eyelid pressure, poor visual habits, lack of outdoor activity, and ocular malnutrition. These factors can lead to changes in the curvature of the cornea and lens, subsequently causing astigmatism.
Astigmatism often occurs simultaneously with myopia or hyperopia and can be treated with eyeglasses, contact lenses, or surgical procedures.
