# Eye diagram with labels

> Free labelled diagram of the human eye with 15 parts, an unlabelled version and a printable worksheet. Learn what each part of the eye does. SVG, PNG, PDF.

URL: https://www.labcanvas.com/diagrams/eye-diagram

The human eye is a fluid-filled ball with a wall of three layers: the tough white sclera (with the clear cornea at the front), the blood-rich choroid, and the light-sensitive retina. Light passes through the cornea, the aqueous humour, the pupil in the iris, the lens and the vitreous humour, and is focused on the retina, where photoreceptors turn it into nerve signals that leave through the optic nerve. This free diagram labels 15 parts and comes unlabelled and as a numbered worksheet with an answer key.

Last updated 26 October 2026

Free download Labelled and unlabelled Printable worksheet CC BY 4.0

Labelled Unlabelled Worksheet

![Labelled diagram of the human eye in side section: eyelids lined by the conjunctiva, cornea, anterior chamber filled with aqueous humour, pupil, iris, lens held by suspensory ligaments from the ciliary body, sclera, choroid, retina with the fovea (macula), optic disc (blind spot), optic nerve and the vitreous humour filling the inside of the eyeball.](https://www.labcanvas.com/diagram-files/eye-diagram/eye-diagram-labeled.svg)

![Human eye diagram without labels](https://www.labcanvas.com/diagram-files/eye-diagram/eye-diagram-unlabeled.svg)

![Human eye labelling worksheet with numbered blanks](https://www.labcanvas.com/diagram-files/eye-diagram/eye-diagram-worksheet.svg)

Human eye diagram by LabCanvas (labcanvas.com), CC BY 4.0

## Download the human eye diagram

[**Labelled (SVG)** Vector, sharp at any size](https://www.labcanvas.com/diagram-files/eye-diagram/eye-diagram-labeled.svg)[**Labelled (PNG)** 3200 px, transparent background](https://www.labcanvas.com/diagram-files/eye-diagram/eye-diagram-labeled.png)[**Unlabelled (SVG)** Vector, sharp at any size](https://www.labcanvas.com/diagram-files/eye-diagram/eye-diagram-unlabeled.svg)[**Unlabelled (PNG)** 3200 px, transparent background](https://www.labcanvas.com/diagram-files/eye-diagram/eye-diagram-unlabeled.png)[**Worksheet (PNG)** 3200 px, transparent background](https://www.labcanvas.com/diagram-files/eye-diagram/eye-diagram-worksheet.png)[**Worksheet + answer key (PDF)** A4, ready to print](https://www.labcanvas.com/diagram-files/eye-diagram/eye-diagram-worksheet.pdf)[**Edit it in LabCanvas** Change colours, labels and layout](https://www.labcanvas.com/editor.html?diagram=eye-diagram)

Free to use in homework, teaching, slides, posters and publications under [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/). Please credit: `Human eye diagram by LabCanvas (labcanvas.com), CC BY 4.0`

## Parts of the human eye and what they do

| # | Part | What it is or does |
| --- | --- | --- |
| 1 | Conjunctiva | Thin mucous membrane that covers the white of the eye and lines the inside of the eyelids, protecting the front of the eye. |
| 2 | Cornea | Clear, curved front part of the outer layer; lets light in and bends (refracts) it towards the retina. |
| 3 | Anterior chamber (aqueous humour) | Space between the cornea and the iris, filled with watery aqueous humour that nourishes the cornea and lens and keeps the eye's shape. |
| 4 | Pupil | The opening in the centre of the iris through which light enters the eye; it looks black because light passing in is absorbed inside. |
| 5 | Iris | Coloured ring of muscle around the pupil; it widens or narrows the pupil to control how much light gets in. |
| 6 | Lens | Clear, flexible structure behind the pupil that changes shape to fine-focus light on the retina (accommodation). |
| 7 | Suspensory ligaments | Fine fibres (zonules) that join the lens to the ciliary body and hold it in place; their tension changes the lens shape. |
| 8 | Ciliary body | Ring of smooth muscle behind the iris; contracting or relaxing it changes the pull on the suspensory ligaments and so the lens shape. It also makes aqueous humour. |
| 9 | Sclera | Tough white outer layer of the eyeball; it protects the eye, keeps its shape and anchors the muscles that move it. |
| 10 | Choroid | Thin layer rich in blood vessels between the sclera and retina; it supplies the retina with blood and its dark pigment absorbs stray light. |
| 11 | Retina | Inner layer of nervous tissue containing the photoreceptors (rods and cones) that turn light into nerve signals. |
| 12 | Fovea (macula) | Small pit at the centre of the macula, packed with cones; the part of the retina that gives the sharpest, most detailed colour vision. |
| 13 | Optic disc (blind spot) | Where the optic nerve fibres and blood vessels leave the retina; it has no photoreceptors, so it cannot detect light. |
| 14 | Optic nerve | Cranial nerve made of the axons of retinal ganglion cells; carries visual signals from the retina to the brain. |
| 15 | Vitreous humour | Clear, jelly-like substance filling the large space behind the lens; it keeps the eyeball round and holds the retina against the choroid. |

## How to label a human eye diagram

**Find the front and back** Light enters on the left. The clear dome at the front is the cornea and the cable leaving the back is the optic nerve.

**Label the three layers of the wall** From outside in: the thick white sclera, the dark red choroid and the pink retina lining the back of the eye.

**Label the front of the eye** Behind the cornea is the anterior chamber of aqueous humour. The blue-grey flaps are the iris and the gap between them is the pupil. The clear oval behind it is the lens.

**Find what holds the lens** The muscle wedges at the edge of the lens are the ciliary body, and the thin fibres from them to the lens are the suspensory ligaments.

**Label the back of the eye** The small pit straight behind the lens is the fovea in the macula. The gap in the retina where the optic nerve leaves is the optic disc, or blind spot.

**Finish with the outside and the inside** The pink membrane over the sclera and inside the eyelids is the conjunctiva, and the gel filling the eyeball is the vitreous humour. Check your answers against the key.

## Rods vs cones

| Feature | Rods | Cones |
| --- | --- | --- |
| Best in | Dim light | Bright light |
| Colour vision | No; vision in shades of grey | Yes; three types respond best to different wavelengths |
| Detail (sharpness) | Low | High |
| Where most are found | Towards the edges of the retina | Concentrated in the fovea |
| In the fovea | No | Yes |
| At the optic disc | No | No |

## How light travels through the eye

Light passes through the **cornea**, the **aqueous humour** in the anterior chamber, the **pupil**, the **lens** and the **vitreous humour** before it reaches the **retina**. The cornea and lens bend the light so that an image is focused on the retina; the image is upside down and reversed, and the brain interprets it. The iris adjusts the size of the pupil: it narrows in bright light and widens in dim light.

In the retina, light even passes through layers of nerve cells before it reaches the photoreceptors at the back. The rods and cones signal to other retinal neurons, and the axons of the retinal ganglion cells gather at the optic disc to form the **optic nerve**.

## The three layers of the eye

The wall of the eyeball has three layers. The outer **fibrous layer** is the white sclera and, at the front, the clear cornea. The middle **vascular layer** is the choroid, the ciliary body and the iris; it carries blood vessels and pigment. The inner **neural layer** is the retina, which contains the photoreceptors.

## Focusing near and far (accommodation)

The lens hangs from the ciliary body by the suspensory ligaments. To look at something far away, the ciliary muscle relaxes, the ligaments pull tight and the lens is stretched flatter. To look at something close, the ciliary muscle contracts, the ligaments slacken and the elastic lens becomes rounder, bending light more strongly. This change in lens shape is called accommodation.

## Quick quiz

**1. Which part of the eye contains the photoreceptors?**

- Choroid
- Retina
- Sclera
- Cornea

**Answer: b) Retina.** The retina contains the rods and cones that turn light into nerve signals.

**2. What controls how much light enters the eye?**

- Lens
- Iris
- Optic nerve
- Vitreous humour

**Answer: b) Iris.** Muscles in the iris change the size of the pupil.

**3. Why can the optic disc not detect light?**

- It is covered by the iris
- It has no photoreceptors
- It is filled with aqueous humour
- It contains only cones

**Answer: b) It has no photoreceptors.** The optic disc is where the nerve fibres leave the eye, and it has no rods or cones.

**4. Which structures hold the lens in place?**

- Suspensory ligaments
- Conjunctiva
- Choroid
- Optic nerve

**Answer: a) Suspensory ligaments.** The suspensory ligaments (zonules) join the lens to the ciliary body.

**5. Where is vision sharpest?**

- Optic disc
- Edge of the retina
- Fovea
- Ciliary body

**Answer: c) Fovea.** The fovea is packed with cones and gives the most detailed vision.

## Frequently asked questions

### What are the parts of the eye?

The main parts of the eye are the conjunctiva, cornea, anterior chamber with aqueous humour, iris, pupil, lens, suspensory ligaments, ciliary body, sclera, choroid, retina, fovea in the macula, optic disc, optic nerve and the vitreous humour.

### What are the three layers of the eye?

The outer fibrous layer (sclera and cornea), the middle vascular layer (choroid, ciliary body and iris) and the inner neural layer (the retina).

### Why is the optic disc called the blind spot?

The optic disc is where the optic nerve and blood vessels leave the eye. It has no rods or cones, so light falling on it is not detected. The brain fills in the gap, so we do not usually notice it.

### What is the difference between the iris and the pupil?

The iris is the coloured ring of muscle; the pupil is the hole in its centre. Muscles in the iris change the size of the pupil to control how much light enters the eye.

### What is the fovea?

The fovea is a small pit in the centre of the macula, directly behind the lens. It is packed with cones and gives the sharpest, most detailed colour vision.

### What is the difference between aqueous humour and vitreous humour?

Aqueous humour is a watery fluid in front of the lens that is constantly made by the ciliary body and drained away. Vitreous humour is a clear jelly that fills the larger space behind the lens and keeps the eyeball in shape.

### Which part of the eye focuses light?

The cornea and the lens together bend light so that it is focused on the retina. The lens can change shape to adjust the focus for near or distant objects.

## Sources

- [OpenStax Anatomy and Physiology 2e, 14.1 Sensory Perception (CC BY 4.0)](https://openstax.org/books/anatomy-and-physiology-2e/pages/14-1-sensory-perception)
- [OpenStax Biology 2e, 36.5 Vision (CC BY 4.0)](https://openstax.org/books/biology-2e/pages/36-5-vision)

Facts on this page follow these introductory textbooks (OpenStax, CC BY 4.0). The diagram is a simplified illustration; organelles are not drawn to scale.

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