Myopia

Myopia is a type of refractive error. When the eye is in a relaxed state of accommodation, parallel light rays from external objects enter the eye, and if their focal point falls precisely on the retina, a clear image is formed, which is called emmetropia. If the focal point does not fall on the retina, it is called ametropia, or refractive error. Myopia is when the focal point falls in front of the retina, resulting in blurred vision for distant objects while near objects appear relatively clear. When symptoms of myopia appear, an ophthalmologist will perform an eye exam and use "myopia degree" to indicate the severity of myopia, with higher degrees indicating greater severity. Mild myopia: ≤300 degrees (≤-3.00 D). Moderate myopia: 300 to 600 degrees (-3.00 D to -6.00 D). High myopia: >600 degrees (>-6.00 D).