Retina: the ten layers, rods and cones !

Organ

The retina is nerve tissue that turns light into signals. Under the microscope it shows ten layers, with the light sensors at the outer edge.

Updated 2026-11-01

See it in 3D: Retina

What it is

The retina is the neural tunic of the eye and, in fact, an outgrowth of the central nervous system. It is described in ten layers that alternate nuclei and synapses: light crosses almost its whole thickness before reaching the rods and cones, which sit on the outside next to the pigment epithelium. This layout explains retinal detachment, macular degeneration and diabetic retinopathy.

Structure

On H&E you see three bands of nuclei (outer nuclear, inner nuclear and ganglion cell layers) separated by two pale plexiform layers, where the synapses are.
Direct signal path: photoreceptor → bipolar cell → ganglion cell; horizontal and amacrine cells make the side connections.
Müller cells are the glia that span the full thickness; their processes form the outer and inner limiting membranes.
Fovea: a central pit with cones only, where the inner layers are pushed aside; the site of sharpest vision.
Optic disc: the exit of the ganglion cell axons; it has no photoreceptors (the blind spot).

Function

Pigment epithelium: engulfs the discs shed by the outer segments, recycles retinal (from vitamin A), absorbs stray light and forms the outer blood-retina barrier.
Rods: contain rhodopsin, are very sensitive in dim light and do not see colour.
Cones: three types of opsin for colour vision; they need brighter light and are concentrated in the macula.

The ten layers of the retina (outer to inner)

Layer	What it holds
1. Pigment epithelium	Simple cuboidal epithelium with melanin, attached to Bruch's membrane
2. Photoreceptor layer	Outer and inner segments of rods and cones
3. Outer limiting membrane	Junctions between Müller cells and photoreceptors
4. Outer nuclear layer	Nuclei of rods and cones
5. Outer plexiform layer	Synapses of photoreceptors with bipolar and horizontal cells
6. Inner nuclear layer	Nuclei of bipolar, horizontal, amacrine and Müller cells
7. Inner plexiform layer	Synapses of bipolar and amacrine cells with ganglion cells
8. Ganglion cell layer	Cell bodies of the ganglion cells
9. Nerve fibre layer	Ganglion cell axons running to the optic disc
10. Inner limiting membrane	Basal lamina of the Müller cells, facing the vitreous

Clinical notes

Age-related macular degeneration: drusen build up between the pigment epithelium and Bruch's membrane; in the wet form new vessels grow in from the choroid.
Diabetic retinopathy: capillary pericytes are lost, microaneurysms form and, later, fragile new vessels grow.
Once separated from the pigment epithelium, photoreceptors lose their metabolic support; that is why retinal detachment is an emergency.

Test yourself

Think of the answer, then tap the question to see it.

Which nuclei make up the outer nuclear layer of the retina?

The nuclei of the photoreceptors, that is, the rods and cones.

Between which layers does the retina split in a detachment?

Between the neural retina (photoreceptor layer) and the pigment epithelium.

Why is the optic disc the blind spot?

Ganglion cell axons leave the eye there and there are no photoreceptors.

Which glial cell spans the full thickness of the retina and forms its limiting membranes?

The Müller cell.

Add to my cards (4)

See it in 3D

The structures of Durgical's 3D anatomy where it is found.

Retina

← All of histology

Educational content on normal microscopic structure and its clinical relevance; no substitute for studying slides or for a health professional's advice.

Sources: 14.1 Sensory Perception (OpenStax, Anatomy and Physiology 2e, 2022); How the Eyes Work (National Eye Institute (NIH), 2026); Retinal Detachment (National Eye Institute (NIH), 2026).

Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake

Representative model, for educational purposes only.