The eyeball gathers the light from the outside and bends it, so that the object can be seen clearly by focusing on it. However, if the refractive index of eyeball to light is abnormal, it will fall into a state of myopia, hyperopia and astigmatism.
Extended data
Computer optometry can be used as a diagnostic optometry for fitting soft contact lenses, which can quickly measure refractive power without mydriasis. The optometry results of computer optometry instrument are all printed automatically without conversion. Generally, a patient can be measured within a few seconds to a few minutes, and the degree of ametropia can be quickly determined, providing more accurate refractive power and pupillary distance for lens correction.
The accuracy of brain optometry is affected by many factors, such as the patient's poor head-eye coordination, walking around, and insufficient eye focus on the target in the optometry instrument, which leads to insufficient relaxation and adjustment, which will inevitably affect the accuracy of diopter examination results, and even the degree of repeated examination is quite different.