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Ophthalmic artery

The ophthalmic artery is the primary arterial supply to the orbit and its contents, including the globe (eye), extraocular muscles, eyelids, lacrimal gland, and part of the face and nose. As a branch of the internal carotid artery, the ophthalmic artery plays a critical role in maintaining the visual and structural integrity of the eye by delivering oxygenated blood to the ocular tissues and surrounding structures. Understanding its origin, course, branches, and imaging appearance is vital in clinical, surgical, and radiological practice.

Synonyms

  • Arteria ophthalmica (Latin)

  • Orbital artery (less commonly used)

Origin

  • The ophthalmic artery arises from the internal carotid artery (ICA).

  • It typically branches off the ICA just after it emerges from the cavernous sinus, at the level of the anterior clinoid process, near the optic canal.

Course

  • Passes anteriorly, entering the orbit via the optic canal along with the optic nerve (CN II).

  • Travels inferolateral (below and to the side) to the optic nerve at entry, then crosses over or under the nerve, usually moving to a superomedial (above and toward the midline) position within the orbit.

  • Continues anteriorly along the medial wall of the orbit, giving off multiple branches to the eyeball and orbital structures.

  • Ultimately, it supplies terminal branches to the forehead and dorsum of the nose (e.g., supratrochlear and dorsal nasal arteries).

Function

  • Supplies arterial blood to:

    • The eye (including retina via the central retinal artery).

    • Extraocular muscles.

    • Eyelids.

    • Lacrimal gland.

    • Parts of the forehead, nose, and ethmoid sinuses.

  • Maintains visual function and nourishment of orbital and periorbital tissues.

MRI Appearance

  • The ophthalmic artery is a small, tubular vascular structure.

  • Normally appears as a flow void (dark signal) on T1- and T2-weighted images due to rapid blood flow.

  • May be visualized using MR angiography (MRA), especially with high-resolution techniques and gadolinium enhancement.

  • Can be identified in the orbital apex, medial to the optic nerve, as it enters the orbit.

  • In cases of vascular pathology (e.g., aneurysm, thrombosis), may see abnormal signal, enhancement, or absence of normal flow void.

CT Appearance

  • On non-contrast CT, the ophthalmic artery is usually not clearly visible due to its small size.

  • CT angiography (CTA) allows visualization as a small, enhancing vessel running parallel to the optic nerve at the orbital apex, then curving medially within the orbit.

  • May be traced from its origin at the internal carotid artery to its intraorbital branches.

  • Calcification or abnormalities (e.g., occlusion, aneurysm) may sometimes be identified in pathological cases.

MRI image

Ophthalmic artery MRI TOF axial image

CT image

Ophthalmic artery CT axial anatomy image -img-00001-00001