Anatomy Of The Eye

Iris: Regulates the amount of light entering your eye. It forms the coloured, visible part of your eye in front of the lens. Light enters through a central opening called the pupil.

Pupil: The circular opening in the centre of the iris through which light passes into the lens of the eye.

Cornea: The transparent circular part of the front of the eyeball. It refracts the light entering the eye onto the lens, which then focuses it onto the retina.

Lens: A transparent structure situated behind your pupil. It is enclosed in a thin transparent capsule and helps to refract incoming light and focus it onto the retina. A cataract is when the lens becomes cloudy, and a cataract operation involves the replacement of the cloudy lens with an artificial plastic lens.

Choroid: The middle layer of the eye between the retina and the sclera. It absorbs excess light, preventing blurred vision.

Ciliary Body: Connects the choroid to the iris.

Retina: A light sensitive layer that lines the interior of the eye. It is composed of light sensitive cells known as rods and cones. The retina works much in the same way as film in a camera.

Macula: A yellow spot on the retina that surrounds the fovea, providing detailed central vision.

Fovea: Forms a small indentation at the centre of the macula and is the area with the greatest concentration of cone cells. When the eye is directed at an object, the part of the image that is focused on the fovea is the image most accurately registered by the brain.

Optic Disc: The visible (when the eye is examined) portion of the optic nerve, also found on the retina. The optic disc identifies the start of the optic nerve where messages from cone and rod cells leave the eye via nerve fibres to the optic centre of the brain. This area is also known as the 'blind spot’.

Optic Nerve: Transfers visual information from the retina to the brain.

Sclera: the white part of the eye, a tough covering with which the cornea forms the external protective coat of the eye.

Rod Cells: are one of the two types of light-sensitive cells in the retina of the eye. There are about 125 million rods, which are necessary for seeing in dim light.

Cone Cells: are the second type of light sensitive cells in the retina of the eye. The human retina contains between six and seven million cones; they function best in bright light and are essential for acute vision (receiving a sharp accurate image).