Hyperopia below 200 (+2.00D) degrees is generally referred to as low hyperopia, above 500 degrees as high hyperopia, and intermediate values as moderate hyperopia. Low farsightedness usually has no clinical manifestations such as physiological farsightedness, which is generally small, and in the physiological state, it is possible to use the extra adjustment ability normally and freely to increase the refractive power of the eye to focus the light on the retina, so as to obtain clear vision in the near and far, but long-term, excessive use may make the symptoms of visual fatigue more obvious. However, for high hyperopia, or at a relatively young age, without giving proper correction, refractive amblyopia can easily form. This is when correction is needed and proper visual training is given. In addition, there are some cases of high farsightedness that use more adjustments when working at close range in order to obtain clear vision, and this is when internal amblyopia or internal strabismus can develop.