The human eye is not perfect. If the cornea is curved at a certain angle and flat at other angles, the light cannot be focused on the retina accurately. This situation is called astigmatism. Astigmatism patients find it more difficult to see the scenery in detail when they see things. In general, astigmatism does not appear alone, and patients' eyes are usually accompanied by myopia or hyperopia.
The correction method of astigmatism is mainly to wear glasses, which have a special curvature at a certain angle to correct the astigmatism of patients' eyes at that angle; Contact lenses or laser correction surgery can also correct astigmatism.
In addition to cornea, the different curvature of lens is another cause of astigmatism.
Astigmatism is caused by the different ability of eyeball to bend light in different directions. The refraction of myopia, hyperopia or normal eyes is like football and basketball, while the refraction of astigmatism eyes is like football. Some directions are tortuous, and some directions are tortuous, so imaging cannot be a point. If you look at the eye chart, you may also find that some directions are easier to identify and some directions are harder to identify. Seeing far and near vision will be affected, and in severe cases, there will be double vision.
Astigmatism is usually innate. If your astigmatism is relatively high and you didn't wear glasses when you were a child, you will see things vaguely from childhood, but because you don't compare yourself, it is more difficult to detect than myopia and farsightedness. When people are born, their eyesight is relatively poor. In order to get full development, they rely on the refractive system to project clear images to the retina to stimulate the development of the fundus. People with high astigmatism have blurred vision, and the fundus is not fully stimulated, which will lead to hypoplasia and amblyopia. If you can't see 1. by optometry and wearing enough glasses, then you have amblyopia. If you are over 1 years old, you are beyond the period of visual development, and amblyopia treatment is basically ineffective.
with or without amblyopia, you can correct it by wearing glasses or contact lenses. If you are wearing astigmatism glasses for the first time, and you are not young, it is best not to over-match the astigmatism at one time (unless you are under 1 years old and need amblyopia treatment), otherwise it is easy to cause the discomfort of visual distortion. Because your brain has accepted the state of astigmatism for a long time, for example, people who are used to watching old TV will feel things concave when they change to flat screen.
If you choose to wear contact lenses, you'd better choose hard contact lenses, which have better correction effect on astigmatism than ordinary contact lenses. However, due to the hard material, long adaptation time and complicated fitting, they are usually available in specialized optical shops and hospitals, but the advantage is good ventilation.
most people's astigmatism will not deepen or decrease. And myopia will deepen. If you are an adult and your myopia is stable, you can also choose to go to the hospital for excimer laser surgery after examination. This type of surgery can not only correct myopia, but also correct astigmatism by designing appropriate patterns and data for you. Under normal circumstances, astigmatism is required to be below 6 degrees, but the effect is better below 2 degrees.