Iris and pupil relationship

What are the functions of the cornea, pupil, lens, retina, and optic nerve? | Socratic

iris and pupil relationship

Lens A transparent, biconvex, flexible disc behind the iris. Pupil The pupil is essentially a hole in the center of your iris that controls how much. A visual inspection of a patient's iris is one of your first opportunities to make a diagnosis. Abnormalities of the iris can result from trauma, infection, neoplasm. Cornea: The outer, transparent structure at the front of the eye that covers the iris, pupil and anterior chamber; it is the eye's primary.

The photoreceptor nerve cells present in the macula and concentrated in the fovea the very center of the macula ; enable people to see fine detail and color.

iris and pupil relationship

The outer, transparent structure at the front of the eye that covers the iris, pupil and anterior chamber; it is the eye's primary light-focusing structure. Deposits of yellowish extra cellular waste products that accumulate within and beneath the retinal pigmented epithelium RPE layer. The pit or depression at the center of the macula that provides the greatest visual acuity.

Anatomy of the Eye

The colored ring of tissue behind the cornea that regulates the amount of light entering the eye by adjusting the size of the pupil. The transparent structure suspended behind the iris that helps to focus light on the retina; it primarly provides a fine-tuning adjustment to the primary focusing structure of the eye, which is the cornea.

iris and pupil relationship

The portion of the eye at the center of the retina that processes sharp, clear straight-ahead vision. The bundle of nerve fibers at the back of the eye that carry visual messages from the retina to the brain. The light sensing nerve cells rods and cones located in the retina.

iris and pupil relationship

The adjustable opening at the center of the iris through which light enters the eye. It is the second part of your eye, after the cornea, that helps to focus light and images on your retina. Because the lens is flexible and elastic, it can change its curved shape to focus on objects and people that are either nearby or at a distance.

iris and pupil relationship

The ciliary muscles, which are part of the ciliary body, are attached to the lens and contract or release to change the lens shape and curvature. The lens becomes more rounded to focus on near objects see Figure 1: A more rounded lens can focus on near objects. The lens becomes more elongated or stretched to focus on objects that are far away see Figure 2: This is called presbyopia and explains why people need reading glasses as they become older.

iris and pupil relationship

The Choroid The choroid is a dark brown membrane that is rich with blood vessels, located between the sclera and the retina. It supplies blood and nutrients to the retina and nourishes all of the other structures within the eye.

What are the functions of the cornea, pupil, lens, retina, and optic nerve?

The Vitreous The vitreous is the jelly-like substance that fills the inside of the back part of the eye. Over time, the vitreous becomes more liquid and can detach from the back part of the eye, which can create floaters. If you notice new floaters or flashing lights, it is important to see your eye doctor, because a detached vitreous can cause a hole a condition called a macular hole to develop in the retina. The Retina and Optic Nerve The retina is the light-sensitive tissue that lines the inside surface of the eye, much like wallpaper.

Cells in the retina convert incoming light into electrical impulses. These electrical impulses are carried by the optic nerve which resembles your television cable to the brain, which finally interprets them as visual images. The macula is the small sensitive area in the center of the retina that provides clear central vision.

The fovea is located in the center of the macula and provides the sharpest detail vision. Some Facts about the Retina The retina is the light-sensitive tissue that lines the inside surface of the eye. The retina contains photoreceptor cells that convert or process incoming light into electrical impulses. There are two types of photoreceptors: Rods The specialized, highly light-sensitive retinal processing cells that are able to function in low light levels.

They are less sensitive to color perception.

Anatomy and Structure of the Eye | BrightFocus Foundation

A normal retina contains approximately million rods, primarily in the peripheral, or outer, retina. Rods provide scotopic vision which refers to eyesight in low light conditions. Cones The specialized retinal processing cells that function in bright light levels and provide central or straight-ahead vision, along with sharp visual acuity, detail, and color vision.