The basic safety of the eyes is guaranteed by the eyelids, which are designed to close lightly at night, allowing the tired eyes to get the most out of their rest. In ancient literature, there are accounts of men who slept at night with their eyes “open in anger”, a representative of “incomplete lid closure”, and whose eyes were actually vulnerable to injury. The eye is protected by the eyelid, although it is only a 24 mm diameter sphere, it is truly perfect: the eye is “made” of water, so that the light zigzags and changes like a dream crystal glass, the main component is the world’s simplest water! Water, with a certain refractive index and the same chemical composition as blood plasma, fills the anterior and posterior chambers, the back four-fifths of the cavity of the eye is vitreous, and 99% of the vitreous composition is water! The human cornea is the most unparalleled photographic lens in the universe, the first one-sixth of the transparent layer of the outermost fibrous membrane of the eyeball wall, making it its mission to penetrate every photon. This exquisite lens is transversely oval in shape, with a horizontal diameter of about 11 mm and a vertical diameter of about 10 mm, a thickness of about 550 microns at the center and just 1 mm at the thicker periphery, and the ability to bend light up to 43 D due to a certain curvature. it is because of the important refractive power of the cornea that most myopic surgery is chosen, whether it is excimer laser or full femtosecond SMILE surgery, the principle is to change the The cornea, the greater the responsibility, the more responsibility! Why is it said since ancient times that “there is no room for a grain of sand in the eye”? The surface of the cornea is under the epithelium is the anterior elastic layer, the anterior elastic layer is traversed by a fine nerve plexus issued by the vertical branch directly to the epithelium, these fine nerves are particularly sensitive, that is why the corneal perception is particularly sensitive! Below the anterior elastic layer is the stroma, which accounts for about 90% of the total thickness of the cornea, the posterior elastic layer and the innermost endothelial layer. The cells of the endothelium are in a beautiful hexagonal shape and act as a “pump”. Corneal transplantation. The junction of the fully translucent cornea and the posterior five-sixths of the fibrous membrane, the porcelain white sclera, is a migrating limbal zone, which is the anterior wall of the anterior chamber angle. The anterior chamber angle is the main drainage pathway for water in the eye. If too much water is produced and not enough is discharged, or if the water production is normal but the drainage channel is blocked, the pressure in the eye will rise and the nerves in the eye will be pressurized and atrophied, resulting in decreased or even lost visual function, leading to “glaucoma”. The second layer of the spherical wall is the uvea, which is divided from front to back into the iris, ciliary body, and choroid. The color of the iris varies from race to race and from individual to individual, from the deep blue of the sea to the mysterious and mysterious “like the night sky” to the dull and misty “like the haze”. The color of the iris changes. The “pupil light” in times of excitement and surprise is the result of the action of the pupil opening muscle and sphincter on the iris. The ciliary body is a workshop for atrial fluid, which is secreted by the ciliary body and nourishes the lens and cornea. The rich vascularity and pigmentation of the choroid determines its function as more than a “dark room”, but also as a valuable nutrient room and one of the keys to information processing in the eye. The innermost layer of the eye wall is the camera “negative” retina, a transparent film thinner than a cicada’s coat, only 13 microns at its thinnest point. The complex structure of the retina is divided into 10 layers, and retinal detachment occurs when the neuroepithelial layer separates from the pigment epithelial layer. Retinal cells, mainly cone cells and rod cells, are far superior to the most delicate and sensitive electronic sensors in their ability to sense and conduct light. There are more than 100 million rod cells, and the closer to the periphery of the retina, the more rod cells perceive dark light, and if there is a problem with the function of the rod cells, you may become “chicken blind” or night blind. The retina has about 65 million cone cells, and the macula has the highest density, with more than 147,000 cone cells per square millimeter in the central macular recess. The excellent visualization of the cone cells depends on the cooperation of all other layers of the retina. The pigment epithelium is specialized in engulfing the membrane discs of the outer segments of photoreceptors, which are essential for maintaining normal visual function. In addition, there is the outer membrane, the outer plexiform layer, the outer nuclear layer, the inner nuclear layer, the inner plexiform layer, the ganglion cell layer and the inner boundary membrane, the layers of which support each other. Only then, each ray of light per reflection, after reaching the retina through the cornea, is transformed into a signal for neural perception, which is then transmitted to the brain through the optic nerve. What does the human eye rely on to adjust its focus? A crystal-like lens hangs in the posterior chamber behind the iris: the lens. It is this lens that adjusts the image by becoming convex or flat when looking close or far, respectively. The refractive power of the lens itself is about 1,900 degrees, so part of the high myopia surgery must target the crystal, for example, for myopia of 1,000 degrees or more, a crystal ICLV4C can be implanted while preserving the crystal, which can precisely and safely achieve clear vision. over the age of 40, the adjustment power of the human lens decreases, and things that are seen near gradually become blurred, which is “aging”. “Over the age of 50, the lens becomes opaque from clear, or becomes opaque due to trauma or other causes, which is called a “cataract. Everyone can develop age-related cataracts, so don’t worry too much! With ultrasound emulsification or femtosecond laser surgery and an IOL implanted in the same location, light is restored. Light reappears, it takes endless efforts to pursue light and spread it …… The blinded mind needs light, the true heart expects light. The thousands of things in the world that are changing in the diffuse earthly world, through light, are reflected on the retina of human eyes, in the minds of human beings, through the refractive interstitial mass of cornea, atrial fluid, lens and vitreous body.