The term insufficient hyperopic reserve is generally used for children before the age of 8, because under normal circumstances, the eye can develop into an orthophoric state only when the eye is about 8 years old, until then there are different degrees of physiological hyperopia, which is called the hyperopic reserve. If the farsightedness reserve is insufficient, it means that the child’s eyes are more likely to become myopic. For example, a 3-year-old child has about 200 degrees of physiological farsightedness under normal circumstances, which can be used for the child’s eye adjustment and development. If the child’s usual eye habits are not very good, resulting in the early development of the refractive state of the eye, for example, only 100 degrees of hyperopia, it means that the child is approximately 100 degrees more myopic than a normal 3 year old child.