Myopia is caused by a change in the refractive state of the eye, such as an increase in refractive power beyond the normal range. Theoretically, there is no maximum limit to the number of degrees of myopia, and the longer the eye axis, the higher the degree of myopia will be, but the length of the eye will not grow indefinitely. From the clinical reality, the highest degree of myopia that can be seen in clinical practice will not exceed 9,000 degrees. In addition to causing vision loss, this kind of myopia has already produced more serious fundus complications, such as retinal detachment, retinal fissure, macular fissure, macular hemorrhage, etc. For myopia of 3000 degrees or more, it is also difficult to maintain normal corrected vision in general. In order to avoid this situation, you must pay attention to reasonable eye habits in general and try to control the rate of myopia growth.