Have you ever wondered about the anatomy of your eye?  If so, here’s a little reminder, or a whole lot of a lesson for those who don’t know.

Our lovely little eye globe sits in two bony sockets, called orbits of the skull.   Inside these orbits, our eye globes are embedded in orbital fat, for their own protection.  Around that, there is a membrane known as the Tenon’s capsule, which separates the globe from the orbital fat, but lets the globe move around freely.

To move our eyes, four rectus and two oblique muscles work to move the globes in different directions.

Eye Globe

How is it made up?

Conjunctiva

The mucus membrane lining the inner surface of the eyelids.

Cornea

The transparent and domed part of our eyeballs that also covers the iris and pupil, letting the light into the eye.

Iris

A muscular diaphragm suspended in the front lens of the eye.   This is the part that gives colour to the eyes, knows as pigment, and excludes light, apart from what is allowed through the pupil.

Lens

The lens sits behind the pupil and focuses incoming light rays onto the retina.

Macula

At around the centre of the retina, this almost all consists of retinal cones, responsible for colour.

Optic Nerve

This nerve carries the necessary electrical impulses from the visual information received by the retina.

Pupil

In the iris, the pupil lets light through to the lens of the eye, allowing it to react with the retina.

Retina

Nervous tissue at the back of an eyeball.  Light hits the tissue and initiates an electrochemical reaction, where electrical impulses are sent to the brain.

Vitreous Humor

Gelatinous mass that occupies space between the lens and retina, compused of 99% water.

Our Vision

Our eyes act similar to a camera, as vision starts when light enters the eye through the cornea.  Light travels through aqueous fluid and passes through the pupil.  As muscles in the iris relax or constrict, the pupil changes size to adjust to the amount of light entering the eye.  When light rays land on the retina, they form an upside down image.  The retina coverts the image to an electrical impulse, travelling along the optic nerve to the brain, where it is interpreted as an upright picture.

Corneal Thickening

Vision is affected if the cornea is thickened and loses transparency due to swelling or fluid build up in the cornea.  This happens after eyes have been closed or had pressure applied for a period of time.  Once eyes opened, air dehydrates the cornea, reducing thickness and restoring vision.