What does ametropia (ametropia) mean??

Absrtact: just like when using the camera, if the focus is not accurate, the picture will be unclear. At this time, if you want to have a clearer image, Glasses (or contact lenses) of appropriate degree must be added to the eyes. The most common refractive abnormalities in clinic include myopia, hyperopia and astigmatism.

Modern people are busy between work and life, and their eyes often feel sore and dry itch. These are the manifestations of eye fatigue. If they are not found and treated in time, they are very likely to cause ophthalmic diseases, such as myopia, hyperopia, astigmatism, etc., which will bring a lot of inconvenience to future work and life.

let’s take a look at the situation of people’s eyes when they suffer from ophthalmic diseases.

what is normal vision?

when our eyes look at things, the external image is focused by the cornea and lens, and then refracted to the retina. The retina receives the image like the negative film of the camera, and then the image signal enters the visual center of the brain through the optic nerve.

the focus of the external image after refraction will just fall on the retina, which is called normal vision.

what are refractive abnormalities?

when the radian of the cornea and the length of the eyeball do not match well, and the distant image cannot be focused on the retina, it will lead to blurred vision, which is called abnormal refraction.

and

are the same as when using the camera, if the focus is not accurate, the picture will be unclear. At this time, if you want to have a clearer image, Glasses (or contact lenses) of appropriate degree must be added to the eyes. The most common refractive abnormalities in clinic include myopia, hyperopia and astigmatism.

about myopia.

after the light enters the eyeball, if the image focus falls in front of the retina, we call it myopia ; The performance of myopia is that distant objects cannot be seen clearly. Generally, it needs to be corrected with concave lens.

about hyperopia

after the light enters the eyeball, if the image focus falls behind the retina, we call it “hyperopia”; Hyperopia is prone to the situation that it is not clear to see far and near, and it is generally necessary to wear convex lenses for correction.

about astigmatism

if the horizontal and vertical radians of the cornea are different, the image forms several different focal points in the eye after focusing through different radians. We call it astigmatism. Astigmatism may form alone or with myopia or hyperopia, which generally needs to be corrected with cylindrical lenses.