Astigmatism, a high frequency word often heard in daily life, many people will confuse it with myopia, thinking it is the same disease, in fact, although they belong to the same refractive error, but they are very different, myopia refers to the parallel light from a distance into the eye focus to the front of the retina, so see the distance is blurred, but see the near place can be adjusted to become clear, while astigmatism refers to the eye on different meridians Astigmatism refers to the difference in refractive power of the eye on different meridians, and the refraction of parallel light rays through the refractive system of the eye does not form a focal point, but two focal lines, which simply means that the light rays through the eye are not focused, forming a scattered object, so there will be double vision. There are many causes of astigmatism, including genetics, trauma, surgery, eyelid pressure, poor eye habits, lack of outdoor activities, etc. Mild astigmatism does not affect vision and can be left untreated, but moderate to high astigmatism has a significant impact on vision and may lead to amblyopia, so glasses are needed. Surgery is also possible after the age of 18. Astigmatism can also be divided into regular astigmatism and irregular astigmatism, the common is regular astigmatism, that is, the eye maximum and minimum refractive power of the two meridians perpendicular to each other, the eye compared to a camera, can be understood as the lens regular, smooth, through the regular astigmatism lens can be corrected, and irregular astigmatism is in the meridian or different parts of the same meridian refractive power is different, can be understood as the lens It is not easy to correct with conventional astigmatism lenses. There are many causes of irregular astigmatism, such as cone cornea, corneal trauma, corneal ulcer, corneal scar, pterygium, cataract, etc. Among them, cone cornea is a common disease that plagues adolescents and causes high astigmatism. Cone keratoconus is a disease that manifests as a localized (usually central) cone-like protrusion of the cornea and thinning of the corneal stroma in the protrusion area, often causing severe irregular astigmatism, high myopia, and progressive vision loss, which may lead to blindness in severe cases. Cone keratoconus occurs in adolescents between 15 and 25 years of age, is more common in males, and has a higher prevalence in Asians. The cause of cone keratoconus is still unclear, and is often related to genetic factors, Down syndrome, Marfan syndrome, pregnancy and other systemic factors, as well as long-term eye rubbing, allergic conjunctivitis, eyelid laxity syndrome and other ocular factors that can easily trigger cone keratoconus. Adolescents with myopia, astigmatism, irregular astigmatism and poor vision correction with conventional glasses should be investigated for cone keratoconus, and should go to the ophthalmology department for corneal topography, corneal thickness, corneal curvature and other examinations. If the results are not good, corneal collagen cross-linking surgery can be performed, and in severe cases, corneal transplantation surgery is required. In daily life, we should try to avoid rubbing the eyes, use anti-allergic eye medication when allergic conjunctivitis occurs, avoid contact with allergic substances, etc. In addition, we should follow the doctor’s instructions for regular review and active treatment to avoid aggravation of the disease.