2 English reference cloth [Chinese medicine terminology Committee]. Terminology of Traditional Chinese Medicine (2004)]
3 Overview Clothing is the general name for the middle and inner layers of the eyeball wall, which has the functions of supplying nutrition, shading and producing vision [1]. Corresponding to what western medicine says about choroid and retina [2]. See Ophthalmology of Traditional Chinese Medicine edited by Guangzhou College of Traditional Chinese Medicine.
4 choroid choroid is located at the back of uvea, starting from the serrated edge in front and ending around the optic disc, between retina and sclera [3]. Rich in blood vessels and pigments.
The choroid is mainly composed of blood vessels. It is divided into five layers from outside to inside: ① suprachoroidal space; ② Great vascular layer; ③ Middle vascular layer; ④ Capillary layer; ⑤ Glass film. It is the most abundant tissue of eyeball blood vessels, accounting for 65% of the total blood of eyeball. It can nourish the outer retina and vitreous body.
There is a space between choroid and sclera, called suprachoroidal space, from which choroidal detachment is separated clinically.
There are no sensory nerve fibers in the choroid, so there is no pain when it is inflamed.
5 retina retina is called optometry in Chinese medicine [3]. It is the inner layer of the eyeball wall. It is located between choroid and vitreous body, before serrate margin, and then reaches optic nerve [3].
The retina is divided into pigment layer and photosensitive layer. The photosensitive layer is a transparent film, but the pigment layer is pigment epithelium. It plays an important role in sensing and conducting nerve impulses.
The serrated edge is the terminal part of the front end of the retina, which looks like a sawtooth, hence the name. It is the end of retinal blood vessels, so its nutrition is poor and it is prone to degeneration.
At the posterior pole of the retina, about 3mm away from the temporal side of the retina, there is a shallow funnel-shaped fovea, called macula, with a range of about 2 mm. There are no blood vessels here, and there is a fovea in the center, which is the most sensitive part of the retina. The pigment epithelial cells in this area contain more pigment, so the color is darker under ophthalmoscope.
There is a disc-shaped area with a diameter of about 1.5 mm and about 3 mm on the nasal side of the macula, which is called optic nerve * * *, or optic disc for short. It is the part where retinal nerve fibers pass through the eyeball, and its center is funnel-shaped, which is called physiological depression.
There is a dark gray point in the depression where the optic nerve passes through the sclera, which is called the scleral cribriform plate. Because there are only nerve fibers and no photoreceptor cells, there is no vision, so it is a blind spot of vision, which is called a physiological blind spot.
The color of optic nerve is red, and there are more microvessels on the optic nerve, and the nasal side is slightly redder than the temporal side. The visual margin is clear, but due to the concentration of optic nerve fibers, the upper, lower and nasal margins are not as clear as the temporal side.
Sometimes a white scleral ring can be seen at the optic margin, because the choroid and pigment epithelium have not yet reached the optic margin.
Retinal tissue can be divided into 10 layers from outside to inside. Namely ① pigment epithelium; ② Visual cell layer (rod body, vertebral cell layer); ③ adventitia; ④ outer granular layer; ⑤ outer plexiform layer; ⑥ Inner granular layer; ⑦ Inner plexiform layer; 8 ganglion cell layer; Pet-name ruby nerve fiber layer; Attending the internal limiting membrane. Pigment epithelium is closely connected with choroid and is not easy to be separated. Clinical retinal detachment is the separation of retina from its own pigment epithelium.
Pigment epithelium is a monolayer hexagonal cell, which is arranged in order. The pigment epithelium in the macula is thick and the periphery is thin, which has many complex biochemical functions and pigment barrier functions to support the activity of photoreceptors. It also has the function of transmitting choroidal nutrition, preventing choroidal blood vessels from leaking into the retina normally, and playing the role of external retinal barrier.
Visual information forms visual nerve impulses in the retina, which are transmitted by three neurons, namely, photoreceptor bipolar cells-ganglion cells. Axons of ganglion cells, that is, nerve fibers, transmit visual information to the visual center along the visual pathway, forming vision.
The first neuron is a photoreceptor cell, which is a specially differentiated neuroepithelium. It consists of two kinds of cells. One is conical, which has the function of feeling strong light and distinguishing colors. Mainly distributed in the macular area, so the vision in the macular area is the most acute. Another kind of cells, such as rod-shaped cells, have the function of sensing weak light, mainly distributed around the retina, and the closer to the macula, the less such cells are, and there is no such cell when the macula is fovea. Normal people have a certain vision in the dark, which is the function of this rod cell. However, the photosensitive pigment of this rod cell is rhodopsin, which needs vitamin A to synthesize. When vitamin A is deficient, the function of rod cells is weakened and objects can't be seen clearly in the dark, which is called night blindness. The second neuron and the third neuron mainly conduct nerve impulses, that is, after the light reaches the visual cell, it generates light pulses through chemical changes, which are transmitted to the bipolar cell (the second neuron), then to the ganglion cell (the third neuron), and then transmitted to the brain by the ganglion cell along the visual pathway to produce vision.