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Optic nerve

Nervus opticus

The second cranial nerve, the optic nerve carries visual information from the retina to the brain, conveying roughly 1.2 million fibers from the retinal ganglion cells to the lateral geniculate nucleus and superior colliculus. It begins at the optic disc, where the ganglion cell axons converge, exits the orbit through the optic canal, and joins its counterpart at the optic chiasm, where the nasal fibers cross before continuing as the optic tract to the lateral geniculate body and visual cortex. Optic neuritis causes acute loss of vision and is associated with multiple sclerosis, while papilledema, swelling of the optic disc, signals raised intracranial pressure. Glaucoma damages the nerve progressively, and a pituitary tumor compressing the optic chiasm produces bitemporal hemianopia.

Begins at the optic disc where retinal ganglion cell axons converge. It exits the orbit through the optic canal and joins the opposite nerve at the optic chiasm, where nasal fibers cross. The optic tract continues to the lateral geniculate body and visual cortex.

On this page
Тип Nerve
Система органов Nervous
Область тела Eye
Латинское название Nervus opticus
FMA ID 50863

Функция

The second cranial nerve (CN II) that transmits visual information from the retina to the brain. It carries approximately 1.2 million nerve fibers from retinal ganglion cells to the lateral geniculate nucleus and superior colliculus.

Клиническое значение

Optic neuritis causes acute vision loss and is associated with multiple sclerosis. Papilledema (optic disc swelling) indicates raised intracranial pressure. Glaucoma causes progressive optic nerve damage. Pituitary tumors can compress the optic chiasm causing bitemporal hemianopia.

Frequently Asked Questions

What is the optic nerve?

The optic nerve is the second cranial nerve (CN II), formed by the axons of retinal ganglion cells converging at the optic disc. It transmits visual information from the retina to the brain's visual processing centers.

Where is the optic nerve located?

The optic nerve exits the posterior orbit through the optic canal and travels to the optic chiasm, where nasal fibers from each eye cross to the opposite side. The optic tract then continues to the lateral geniculate body and visual cortex.

What is the function of the optic nerve?

The optic nerve carries visual signals—in the form of action potentials from retinal ganglion cells—from the eye to the brain. This pathway enables the brain to process and interpret visual images.

What conditions may be associated with the optic nerve?

The optic nerve may be involved in conditions such as optic neuritis, glaucoma, and compressive lesions at the optic chiasm. Damage at the chiasm may be associated with visual field defects such as bitemporal hemianopia.

What does the optic nerve look like?

The optic nerve appears as a cord-like white structure about 5 cm long, surrounded by meningeal sheaths. On fundoscopy, its origin is visible as the optic disc—a pale, circular region at the back of the eye where retinal fibers converge.

References

  1. Foundational Model of Anatomy — FMA:50863 Reference anatomy ontology (University of Washington)
  2. Wikipedia — Optic nerve Encyclopedia article (verified cross-reference)

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Educational Disclaimer

This content is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider for medical decisions.

Data sources: Terminologia Anatomica, Foundational Model of Anatomy, Wikidata.