Where is the choroid layer of the eye

The iris controls the amount of light that enters the eye by opening and closing the pupil. The iris uses muscles to change the size of the pupil. These muscles can control the amount of light entering the eye by making the pupil larger dilated or smaller constricted. Posterior chamber: The posterior chamber is between the iris and lens. The lens is behind the iris and is normally clear.

Light passes through the pupil to the lens. The lens is held in place by small tissue strands or fibers zonules extending from the inner wall of the eye.

The lens is very elastic. Small muscles attached to the lens can change its shape, allowing the eye to focus on objects at varying distances. Tightening contraction or relaxing these muscles causes the lens to change shape, allowing the eyes to focus on near or far objects accommodation. Vitreous chamber: The vitreous chamber is between the lens and the back of the eye.

The back two-thirds of the inner wall of the vitreous chamber is lined with a special layer of cells the retina : millions of highly sensitive nerve cells that convert light into nerve impulses. Nerve fibers in the retina merge to form the optic nerve , which leads to the brain. Select basic ads. Create a personalised ads profile. Select personalised ads. Apply market research to generate audience insights.

Measure content performance. Develop and improve products. List of Partners vendors. The choroid is the vascular layer of the eye that lies between the retina and the sclera. The choroid is thickest in the back of the eye, where it is about 0. The choroid forms the uveal tract, which includes the iris and the ciliary body. The dark-colored melanin pigment in the choroid absorbs light and limits reflections within the eye that could degrade vision. The choroidal pigment is what causes "red eyes" when flash photographs are taken.

Besides providing a major supply of oxygen and blood supply to the retina, the choroidal blood flow may cool and warm the retina. The choroid can also change thickness, and these changes can move the retina forward and back, bringing the photoreceptors into the plane of focus. Funding for Cancer Training. Building a Diverse Workforce.

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It is associated with high pressure in the eyes and can occur during surgery. It is usually more painful than a serous detachment. Choroid plexus papilloma — Rare, benign brain tumor that develops in the choroid plexus tissue that makes cerebrospinal fluid.

Chorioretinitis — Inflammation of the choroid caused by infection or an autoimmune disease. Choroideremia — A hereditary, progressive deterioration of the choroid; this condition primarily affects men. During a fundoscopic eye exam , your eye doctor will use a tool that allows them to view the back of the eye, where the choroid is located. Using this method, they can determine the health of the choroid and prescribe treatment if they detect a problem.

National Cancer Institute. Accessed September The multifunctional choroid. Progress in Retinal and Eye Research.