A condition in which one eye is very nearsighted and the other eye is not nearsighted or has mild myopia is called refractive parallax. The cause of myopia is due to unreasonable eye habits, so if you favor one eye in your reading habits, this eye will be more myopic than the other eye, so this is a very common condition in ophthalmology. For refractive disparity, it is important to go to the hospital for an early optometric examination and wear glasses, which can firstly improve vision and maintain clear visual quality; it can avoid the occurrence of strabismus or amblyopia, especially children should correct it early, because the difference between the refractive power of two eyes is very easy to lead to strabismus or amblyopia these diseases.