Anatomy of the Eye

Front view of both eyes showing the eyelids, eyebrows, and surrounding facial forms.

The eyes are one of the most important parts of the human face. They reflect a character’s emotions and mood. In many drawing styles, the eyes are the main focus.

You can see this effect in anime-style eye drawings, for example.

Here we will tell you about the anatomy of the eye. More precisely, we will focus on those aspects of eye anatomy that are important for artists.

Some basic knowledge of anatomy is useful for artists, doctors, and scientists alike. First of all, it is necessary to understand that the eye consists of the eyeball and the accessory organs of the eye. These include the eyelids, lacrimal apparatus, eyebrows, and eye muscles.

This basic article will give you important knowledge that will be useful for drawing eyes and constructing convincing portraits.

Eyeball Anatomy

The eyeball consists of three membranes that surround the inner parts of the eye. Now we will talk a little about each of these three membranes.

Fibrous Membrane

This is the outermost layer. The fibrous membrane of the eye is quite dense and forms a protective outer layer for the other parts of the eyeball.

The fibrous membrane consists of two parts. The transparent front part is called the cornea. The cornea must be transparent because light passes through it on its way into the eye.

The second part of the fibrous membrane is called the sclera and is an opaque layer. It forms the white part of the eye that surrounds the cornea.

Choroid

The choroid is the middle layer of the eyeball. For artists, an important part of this layer is the iris, which gives the visible eye its color. The iris contains melanin, and differences in the amount and distribution of this pigment contribute to different eye colors.

At the center of the iris is an opening called the pupil. Contrary to a common misconception, the pupil is not an independent part of the eye but an opening that allows light to enter the eye.

Eyeball anatomy with the cornea, iris, choroid, pupil, and sclera labeled.

Retina

The retina is the light-sensitive layer of the eye. The other parts of the eye help direct and focus light onto the retina. The retina contains receptors that detect light and convert it into nerve signals.

The Nucleus of the Eye

The inner part of the eye contains several transparent, light-refracting media through which light passes before it reaches the retina.

Anterior Chamber

The anterior chamber is the space between the cornea and the iris and is filled with a small amount of intraocular fluid called aqueous humor. In a healthy eye, aqueous humor is transparent.

Lens

The lens is a small, flexible, transparent part of the eye. It is connected by fibers to the ciliary body. Changes in the shape of the lens allow the eye to focus on objects at different distances.

Posterior Chamber

The posterior chamber is a small space behind the iris and in front of the lens and ciliary body. It contains the same clear aqueous humor found in the anterior chamber.

In this illustration, the anterior chamber of the eye is highlighted in red and the posterior chamber is highlighted in blue.

Cross section of the eye showing the anterior and posterior chambers.

Vitreous

The vitreous fills the large space behind the lens and helps maintain the rounded shape of the eyeball. It has a gel-like consistency and, like the other light-transmitting media of the eye, is transparent.

Accessory Organs of the Eye

The accessory organs of the eye are anatomical structures that protect the eye and support its functions. In this article, we will only cover those that are important for plastic anatomy.

Eyebrows

Eyebrows are areas of short, coarse hair located above the eye sockets. They help protect the eyes from sweat and also play an important visual role in the face.

Eyebrows can have a variety of shapes. Some people have very light eyebrows that may be difficult to see, while others have thick, dark, or gray eyebrows. The position and shape of the eyebrows also help convey different emotions.

External eye anatomy with the eyebrow, eyelashes, upper eyelid, and lower eyelid labeled.

Eyelids

The eyelids are movable folds located above and below the eyes. They protect the eyes from dust and other foreign particles and can close completely over the eyeballs when necessary.

The eyelids are also important for conveying emotion. Wide-open eyes can suggest strong emotions such as surprise, fear, or anger, while half-closed eyelids can create a calmer or more relaxed expression.

Lacrimal Apparatus

The lacrimal apparatus is a group of structures involved in the production and drainage of tears. Many parts of the lacrimal apparatus are not visible in a living person, but artists can see the lacrimal lake and the lacrimal caruncle at the inner corner of the eye.