Under-concentrated intermittent exotropia sometimes occurs after encephalitis, diphtheria with streptococcal infection, macromonocytosis and car accidents. Some patients have a gradual onset over many years, with symptoms slowly worsening. Hypoconcentration with hyporegulation sometimes occurs after encephalitis, streptococcal diphtheria, macromonocytosis and car accidents. Some patients have a gradual onset over many years with a slow worsening of symptoms. There are no specific findings in the medical history. Some have a history of high fever in childhood, so some authors suggest that subclinical encephalitis may be the cause of the disease. These patients have more severe symptoms and, unlike the functional abnormality category, do not respond to orthostatic visual training and rarely resolve. The patient has a distant or even inability to focus the near point of assembly; the near point of accommodation is significantly distant. the AC/A is extremely low9 or even 0. Stimulation of the accommodation mechanism with a negative spherical lens does not induce an assembly response. The treatment mostly uses positive spherical lenses and bottom-inward trigeminal lenses to help reading. The principle of giving prescriptions is to give as few degrees of trigeminal and positive spherical lenses as possible, as long as comfortable reading vision can be obtained. In order to maintain good correction, it is important to review the glasses regularly and adjust the prescription at any time. Therefore, it is convenient to apply trigeminal lenses with pressure on the ortho-phthalmoscope. ”Astigmatism” sounds more mysterious to most people than myopia or farsightedness. Many parents are nervous when they hear that their child has astigmatism. In fact, there are many cases of astigmatism that are physiological in nature and can be treated without special treatment if they do not affect vision. However, astigmatism that is relatively large or growing in magnitude is something that we should pay close attention to. Astigmatism is due to the inconsistency of the refractive power of the whole refractive system in two meridians. In fact, since the cornea and lens occupy the majority of the refractive power of the entire refractive system, the source of astigmatism in the eye is mainly the cornea and the lens, with the cornea being the dominant source. Some studies have reported that the corneal source of astigmatism accounts for 80% of the astigmatism in the eye. The uneven surface curvature of each refractive component of the eye, local changes in the refractive index of the refractive component, and deviation from the optical center of the refractive component can all cause astigmatism. The uneven curvature of the corneal surface is the main factor. Astigmatism is common in infants and children, and some studies have reported that 1/4-1/2 of infants and children younger than 1 year old have more than 1D of astigmatism, and that astigmatism is mainly of corneal origin, which will gradually decrease with age. The astigmatism measured by optometry is the total astigmatism of the eye, including the corneal astigmatism and the intraocular astigmatism. Astigmatism of corneal origin accounts for the majority of all astigmatism, and astigmatism greater than 1D does not disappear on its own and does not change much with age (except for cone corneas). Astigmatism mainly causes vision loss and visual fatigue symptoms. It mainly relies on columnar frame glasses to correct vision. For those with high astigmatism who cannot adapt to frame glasses, if the astigmatism mainly originates from the cornea, gas permeable rigid corneal contact lenses (RGP) can be chosen to correct vision. The way to determine whether the astigmatism is of corneal origin is corneal topography. If the astigmatism continues to grow, corneal topography can also be performed regularly to closely observe the changes in corneal morphology, and corneal topography can also be performed to screen for other corneal diseases. In order to treat astigmatism, the surgery is mostly done by bilateral internal rectus muscle truncation.