It is said that the eyes are the windows of the soul, but also the window for us to watch this vast and prosperous world, don't look at the eyes in our bodies only a small proportion, but it contains complex structures and huge mysteries.
Structure of the eye:
The human eye is a spheroid organ located in the orbit, and the composition of the eyeball consists of the eyeball wall, the intraocular cavity and contents, nerves, blood vessels and other tissues. The simple classification of the structure of the eyeball is mainly divided into two parts: the wall of the eyeball and the contents of the eyeball:
1． Eyeball wall: can be divided into outer membrane, middle membrane and inner membrane.
(1) The outer membrane is composed of a colorless, transparent, colorless cornea rich in nerve endings that can pass through light and a white and tough scleral membrane that protects the eyeball; (2) the middle membrane is composed of an iris that can adjust the brightness of the light entering the eye, a ciliary membrane that regulates the curvature of the lens, and a choroid that can block light to form an anechoic chamber; (3) The inner membrane is what we usually call the retina, which is the light-sensitive system of the eye, and there is the most visually sensitive macula in the center.
2． The contents of the eye include aqueous humor, crystals, and vitreous bodies, all of which are transparent in color and act as refractive media along with the cornea.
Now that we have a brief understanding of the structure of the eye, let's take a look at how our eyes perceive light:
Our eyes are like a precision camera, the cornea on the surface of the black eyeball is like a lens on the camera, the middle pupil is like a circle of light that controls the amount of light entering the eye, the lens behind is like a zoom that adjusts the clarity of the object, the inner retina is like a film that senses the light source, and finally the object is imaged on the retina. Light signals are transmitted to the visual center of the brain through the visual nerve, and after the processing of the visual center, we can see clear and beautiful things. [1]
So how does myopia form?
Myopia is a type of refractive error. It is when our eyes are in a state of adjustment and relaxation, parallel light enters the eye, it can not focus on the retina to form a clear image, myopia is thus formed. Myopia can be divided into mild myopia (≤ 300 degrees), moderate myopia (300 degrees to 600 degrees) and high myopia (600 degrees).
What are the causes of myopia?
(1) Genetic factors, some people are born with an eye axis that is too long, and they are myopic at birth. This may be related to parental myopia, and studies have shown that if one parent has myopia greater than 600 degrees, the probability of inheritance to the next generation is about 20%; if both parties are myopic, the next generation myopia rate is as high as 40%. Therefore, for the sake of the next generation's eye health and reduce the chance of suffering from myopia, please protect our eyes.
(2) Light factor: "The mobile phone emits dim light, and the small characters on the mobile phone are densely packed, and they stare for several hours." "The lights are good, the tone is the brightest, otherwise the writing can't be seen clearly." When the light is too weak, in order to see clearly, the thing will be held very close, and the ciliary muscle will enter tension mode. The light is too strong to illuminate the pupil, it will make the pupil narrow, and will make the ciliary muscle tense, the crystal wants to change a flat posture, but it is tightly restricted by the ciliary muscle, and myopia will come to the door.
(3) Bad posture: Some people like to lie down, play with mobile phones or read books, how comfortable the posture is, completely do not consider the feeling of the eyes, long-term so will make the ciliary muscles in a tight state, so that myopia is not far away from us.
(4) Lack of eye relaxation: "Stay up late to chase the drama until 12 o'clock in the middle of the night, iapd, computer, mobile phone like not to fall" This should be a portrayal of the daily life of modern young people, everyone likes to relax themselves at night against electronic products, a chase drama or play a game is a whole night, there is no time and opportunity for the eyes to relax, so the intensity of the eyes so that the eyes can not be relaxed, the final end is also myopia.
(5) Vitamin deficiency:: Vitamin B1 is a kind of optic nerve nutrition if there is a long-term lack of vitamin B1, which will lead to vision loss due to insufficient nutrition of the eyeball.
(6) Lack of calcium: Calcium is the "protector" of the eye, if calcium is lacking, the ciliary muscle will lose its elasticity, which is very easy to cause our eyes to appear myopia.
The eyes are an indispensable part of our daily life, but we do not pay attention to the protection of the eyes, resulting in a higher and higher rate of myopia, I hope that everyone can pay attention to eye protection and reduce the occurrence of myopia.
References:[1] Cypress Shuling, editor-in-chief. Systematic Anatomy (Seventh Edition), People's Medical Publishing House, 2010