The human eye is like a camera, and external objects need to focus accurately on the negatives in order to get a clear picture. Myopia is a kind of refractive state in which the light emitted by distant objects cannot focus on the retina and focus on the front of the retina when the human eye is adjusting and relaxing, so it can not form a clear image on the retina and cause blurred vision.
According to the severity of myopia is divided into low, moderate and high, high myopia refers to myopia more than 600 degrees of myopia.High myopia is often accompanied by pathological changes of the eye, which can lead to serious visual impairment. The statistics of large sample of Chinese people show that the proportion of high myopia in blind and low vision population is 7- 11, which is the second leading cause after cataract.
High myopia may cause a series of ocular pathological changes, also known as pathological myopia. These changes include: abnormal scleral collagen fibers, scleral thinning and dilatation; ciliary atrophy; vitreous degeneration, liquefaction, destruction of normal reticular structure; Progressive choroidal atrophy and thinning, pigmentation and angiogenesis; retinal atrophy, degeneration and even hiatus.
With the above changes, the clinical manifestations of high myopia and the resulting eye diseases are varied. The continuous prolongation of the axis of the eye leads to the rapid decline of vision and the deepening of myopia, which is different from the simple myopia with stable degree of myopia after a certain age, and the myopia degree of some high myopia patients is still deepening after adulthood. With the continuous lengthening of the axis of the eye, some people have prominent eyeballs, poor visual acuity and damage of binocular visual function will also lead to amblyopia and strabismus; Degeneration, atrophy and traction of the vitreous and retina can lead to retinal rupture or even retinal detachment, and choroidal retinal atrophy will result in neovascularization in the fundus of the eye. Rupture of neovascularization leads to retinal macular hemorrhage and scar formation, resulting in uncorrected loss of vision. In addition, glaucoma is closely associated with high myopia, and cataracts develop earlier than in the general population.
At present, the overall cause of myopia is not clear, it is believed that genetic factors and environmental factors together cause the occurrence and development of myopia. The occurrence of high myopia or even pathological myopia and genetic relationship is greater, parents or one of the high myopia, children will increase the likelihood of myopia. A serious threat to vision.
The basic treatment of high myopia is to improve visual acuity and delay the development of myopia by various means. The methods of improving visual acuity include wearing frame glasses or contact lenses, undergoing excimer laser or femtosecond laser corneal refractive surgery and intraocular lens implantation after the adult and myopia develop steadily. Delaying the development of myopia mainly depends on the daily healthy use of the eyes and the choice of correct refractive correction methods. The technique of posterior scleral reinforcement can also be used to delay and alleviate the pathological changes of sclera, retina and choroid.