【 myopia research 】 the pathogenesis of acquired myopia

original title: [deep exploration of myopia] pathogenesis of acquired myopia

myopia can be divided into different types according to different classification methods. Today, I share with you the relevant contents of acquired myopia.

Acquired myopia refers to high-intensity use of the eyes, refractive state and naked vision are in the normal range, and then myopia occurs. And this myopia will continue to develop in a certain period of time. At present, there is no definite conclusion about the pathogenesis of myopia, and its research is still in the contention and exploration of many theories. The following is a variety of theories

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01 regulation theory

in the research on the mechanism of acquired myopia over the years. The visual signal of near vision work is transmitted through the optic nerve, through the optic center and from the parasympathetic nerve, causing ciliary muscle contraction and regulation reaction. Therefore, near vision work may cause myopia due to regulation reaction. However, it is still controversial whether accommodation lag is the cause of myopia or a result of myopia. There are also theories that long-term near vision work causes continuous regulatory tension, which leads to the growth of ocular axis and the occurrence and development of myopia through the mechanical conduction of ciliary muscle choroid sclera.

02 optical defocus theory

moderate hyperopia defocused retinal image signal leads to compensatory growth of sclera, accelerates the extension of ocular axis, and forms myopia, while focused retinal image slows down the growth of eyeball. This view can explain the emmetropia process and lens induced compensatory growth process with the mechanism of “visual dependence and focusing growth” to a certain extent, but this view can not explain all the results of hyperopia defocus.

03 form deprivation theory “the decrease of contrast of retinal image of

is the main cause of form deprivation myopia. The degree of myopia is directly related to the decrease of contrast of retinal image produced by scattering lens. However, in humans, myopia caused by form deprivation is only seen in secondary myopia caused by congenital ptosis or refractive interstitial opacity, such as corneal scar and cataract. Therefore, it is not the main pathogenesis of acquired myopia in human adolescents.

04 theory of extraocular muscle and eyeball pressure

Greene studied the influence of extraocular muscle contraction and adjustment on sclera with engineering method, and proposed that extraocular muscle will produce mechanical tension on sclera, while adjustment may have little effect. Some researchers believe that continuous adjustment during close eye use will lead to the increase of intraocular pressure, resulting in the growth of eyeball and the occurrence of myopia. However, in some studies, it is found that the intraocular pressure measured by cornea decreases with adjustment. This theory is not the mainstream view of the pathogenesis of myopia, and has not been widely recognized.

05 scleral active shaping theory

Norton et al. Used the method of form deprivation to find that the DNA level of sclera of tree mice covering eyes is consistent with that of control eyes, indicating that there is no excessive proliferation of cells in sclera of form deprivation myopia. The control of ocular axis growth mainly lies in the regulation of scleral resistance rather than scleral growth.

06 bioactive substance action theory

research shows that a variety of bioactive substances in the retina, such as dopamine, vasoactive intestinal peptide, acetylcholine, glucagon and some growth factors, play an important role in the process of eye growth, eye axis elongation and the occurrence and development of myopia.

07 optical defocus theory

in recent years, Pax6 and egr-l genes are considered to be regulatory genes closely related to the process of eye growth and development, which may be related to the occurrence of myopia.