Pediatric myopia is myopia, a type of refractive error that differs from the characteristics of adult myopia. Myopia (nearsightedness) refers to a refractive state in which parallel light rays pass through the refractive system of the eye and fall in front of the retina when the eye is relaxed. Pediatric myopia refers to the onset of myopia in childhood and is characterized by abnormal regulation, progressivity, and susceptibility to multifactorial interference. What are the precursors before myopia occurs in adolescents? 1, eye fatigue symptoms: manifested as reading a book is, there is a feeling of heavy handwriting, floating unstable or frowning phenomenon of looking at things. Some people move to near objects after looking at far objects for a long time, or move to far objects after looking at near objects for a long time, there will be a brief blurring phenomenon in front of the eyes. This is a manifestation of sluggish regulation of the ciliary muscle of the eye, which is caused by eye fatigue. As the degree of eye fatigue increases day and night, the day of myopia is gradually approaching, these children usually frown when looking at things, like to sit forward. 2, perceptual allergy symptoms: This refers to the eye sensory nerve fatigue type perceptual allergy, many people will also be accompanied by eye dryness, burning, itching and eye swelling pain, some people swelling pain can spread to the deep part of the eye orbit, some even cause migraine, and even neck, shoulder and back parts of the pain. 3, systemic nerve disorder symptoms: some students who had good grades become bored with learning, do not pay enough attention when listening to lectures, and their reactions are also a bit slow, their temper also becomes impatient, and they lack interest in their favorite things, their academic performance decreases, they have insomnia and dreaminess at night, their bodies are easily tired, and they have symptoms such as vertigo and loss of appetite. These are the manifestations of central and vegetative nerve dysfunctions caused by eyestrain, and are also the information that myopia is about to arise.