Posterior segment of eyeball

Posterior segment of eyeball refers to the back two-thirds of the eye that includes the anterior vitreous, vitreous body, retina, choroid, and optic nerve. It is a crucial part of the visual system, responsible for receiving and processing light to create visual images.

Anatomy

The posterior segment is primarily composed of the following structures:

• Anterior vitreous: This is the front part of the vitreous body, a clear gel that fills the space between the lens and the retina.
• Vitreous body: The vitreous body is a clear, jelly-like substance that fills the space between the lens and the retina. It helps to maintain the shape of the eye and transmit light to the retina.
• Retina: The retina is a thin layer of tissue that lines the back of the eye. It contains millions of light-sensitive cells (rods and cones) and other nerve cells that receive and organize visual information.
• Choroid: The choroid is a layer of blood vessels and connective tissue between the sclera and the retina. It provides oxygen and nutrients to the outer layers of the retina.
• Optic nerve: The optic nerve is a bundle of more than one million nerve fibers that transmit visual signals from the retina to the brain.

Function

The primary function of the posterior segment is to convert light into neural signals and send these signals to the brain for visual recognition. The retina plays a crucial role in this process. When light enters the eye, it is focused onto the retina by the cornea and the lens. The light-sensitive cells in the retina then convert the light into electrical signals. These signals are sent to the brain through the optic nerve, where they are interpreted as the images we see.

Diseases and Disorders

Several diseases and disorders can affect the posterior segment of the eyeball, including:

• Retinal detachment: This is a serious condition where the retina pulls away from the blood vessels that supply it with oxygen and nutrients.
• Macular degeneration: This is a disease that destroys the sharp, central vision needed for seeing objects clearly and for tasks such as reading and driving.
• Glaucoma: This is a group of eye conditions that damage the optic nerve, often caused by abnormally high pressure in the eye.
• Diabetic retinopathy: This is a diabetes complication that affects the eyes and is caused by damage to the blood vessels of the light-sensitive tissue at the back of the eye (retina).

See Also

• Eye
• Visual system
• Ophthalmology