With the development of society, the knowledge we need is constantly increasing, the probability of using eyes greatly increases, and the chance of myopia also increases. In medicine, according to the diopter (D), which is the unit indicating refractive power, myopia is divided into three types. Among them, high myopia has a diopter over 6.00D, that is, the degree of myopia is greater than 600 degrees, femtosecond laser.
Common myopia generally has a degree lower than 600 degrees. Myopia belongs to polygenic inheritance, meaning patients have multiple causative genes, but environmental factors also play a role, which is more obvious in common myopia. Environmental factors include poor lighting, bad reading and working habits, such as long-time reading and close-range work, where the eye's adjustment muscles are in a continuous state of tension and contraction, thereby weakening the adjustment ability and causing myopia. But under the same conditions, not all people develop myopia, and some myopic patients do not engage in close-range work or rarely read newspapers and books, so it is the result of the interaction of both factors.
High myopia refers to myopia with a degree greater than 600 degrees, accompanied by elongation of the eye axis, atrophy of the retina and choroid, and other degenerative lesions as the main characteristics of refractive errors. Less than 300 degrees is mild myopia, while between 300 to 600 degrees is moderate myopia. If you want to consider laser myopia correction treatment, it is recommended to come to the hospital first to check the corneal thickness and corneal curvature rate and other ocular conditions. Usually, laser surgery is suggested to retain more corneal thickness and improve visual quality.
The causes, pathogenesis, treatment, and prevention of high myopia are different from common myopia. In our country, high myopia is autosomal recessive inheritance. It manifests as myopia appearing during the school-age (pre) period of children, progressive increase in myopia degree, and annual aggravation of retinal and choroidal lesions in the fundus, thus producing many serious complications. Therefore, high myopia is also called pathological myopia, malignant myopia, degenerative myopia, progressive myopia, and hereditary myopia.
Source: http://www.kjwm.com/jinshi-ask/jinshi-1897.html