What is the physiological structure and function of the eye?

The lens in the eyeball is a transparent tissue, and once the lens is cloudy for any reason, it is called cataract, so cataract is a disease that occurs on the lens in the eyeball. According to this, any opacity of the lens can be called a cataract, but when the opacity of the lens is mild, it does not significantly affect vision without being noticed or ignored and is not included in the cataract category. According to surveys over the years, cataract is the most common cause of blindness and visual disability, and it is estimated that about 25% of humans suffer from cataract, fortunately, it is an eye disease that is prone to**.

What is glaucoma? Glaucoma is a group of eye diseases that permanently damage the optic nerve, which can lead to blindness in severe cases. It is the leading blinding eye disease in adults worldwide.

The visual impairment caused by glaucoma generally starts from both sides of the visual field, and the vision will gradually narrow, most of the glaucoma is ** and difficult to detect in the early stage of the disease, therefore, many patients often do not realize that they have suffered from the disease, until their visual field is only less than 20%. How does glaucoma damage the optic nerve? Glaucoma is mainly caused by an increase in pressure inside the eye (intraocular pressure).

Located in front of the eye is the anterior chamber, where a clear secretion (aqueous humor) flows in and flows out through a spongy curtain at the corner of the anterior chamber, if the flow of aqueous humor is blocked, the intraocular pressure will rise, which may lead to permanent damage to the optic nerve.

The human eye is approximately spherical. The eyeball includes tissues such as the wall of the eyeball, its contents, nerves, and blood vessels.

The eyeball wall is mainly divided into three layers: outer, middle, and inner.

The outer layer is made up of the cornea and sclera. The first 1 6 is a transparent cornea, and the remaining 5 6 is a white sclera, commonly known as the "white of the eye". The outer layer of the eye maintains the shape of the eye and protects the tissues inside the eye.

The cornea is the transparent part of the front of the eye through which light rays enter the eyeball. The sclera is opaque, milky white, and tough in texture.

The middle layer is rich in pigments and blood vessels, including the iris, ciliary body, and choroid.

Iris: Ring-rounded, located in front of the lens. People of different races have different iris colors.

**There is a round hole, called the pupil. The ciliary body is connected anteriorly to the base of the iris, to the choroid, to the lateral sclera, and medially to the lens by the suspensory ligament. The choroid is located between the sclera and the retina.

The blood circulation of the choroid nourishes the outer layer of the retina, and the rich pigment it contains acts as a darkroom.

The inner layer is the retina, which is a transparent membrane and the most acute area for the transmission of nerve information formed by vision. The visual information received by the retina is transmitted to the brain through the optic nerve.

Ocular contents include aqueous humor, lens, and vitreous.

Aqueous humor is produced by the ciliary process, which nourishes the cornea, lens and vitreous humor, and maintains intraocular pressure.

The lens is an elastic, transparent body shaped like a biconvex lens, located behind the iris, behind the pupil, and before the vitreous.

The vitreous is a transparent colloid, and the main component is water. The vitreous humor has a refractive role and also plays a role in supporting the retina.

The eyeball includes tissues such as the wall of the eyeball, the intraocular cavity and contents, nerves, and blood vessels.

1. Eyeball wall: The outer layer of the eyeball plays a role in maintaining the shape of the eyeball and protecting the tissues in the eye.

2. Tear cavity: Aqueous humor is produced by the ciliary process, which has the function of nourishing the cornea, lens and vitreous humor and maintaining intraocular pressure.

3. Optic pathway: the entire nerve impulse transmission pathway from the retina receiving visual information to the visual cortex of the brain to form vision.

4. Eye accessory: The main function is to protect the eyeball, because it is often blinking, it can make tears moisten the surface of the eyeball, keep the cornea shiny, and clean the dust and bacteria in the conjunctival sac.