Ophthalmic artery

Medically Reviewed by Anatomy Team

The ophthalmic artery is a crucial artery that arises from the internal carotid artery and supplies blood to the structures of the eye, orbit, and surrounding areas. It is the primary source of oxygenated blood for the eye and its associated structures, making it vital for maintaining proper ocular function and health.

Location

The ophthalmic artery originates from the internal carotid artery as it emerges from the cavernous sinus within the skull. It enters the orbit through the optic canal, traveling alongside the optic nerve. Once inside the orbit, the artery branches into several smaller vessels, including the central retinal artery and the lacrimal artery, which supply blood to the retina, optic nerve, extraocular muscles, and surrounding structures. The ophthalmic artery’s course within the orbit is highly variable, adapting to the complex anatomy of the region.

Structure and Anatomy

The ophthalmic artery is a key vessel in the ocular and orbital blood supply. It has a complex course with numerous branches that serve the eye, orbit, and nearby facial structures. Below is a detailed description of the anatomy of the ophthalmic artery.

Origin

The ophthalmic artery arises from the internal carotid artery (ICA). It typically originates just as the ICA exits the cavernous sinus, in the region where the ICA transitions from its horizontal to vertical segments, which is referred to as the supraclinoid portion of the ICA. The artery originates medially and inferiorly to the optic nerve.

Course

The ophthalmic artery follows a complex anatomical path as it enters the orbit. After branching off from the internal carotid artery, it passes into the orbit through the optic canal, traveling inferior and lateral to the optic nerve. Once it enters the orbital cavity, it crosses over the optic nerve, moving to a more medial position. The artery then travels anteriorly within the orbit, supplying various ocular and orbital structures through its numerous branches.

Segments

The course of the ophthalmic artery can be divided into several segments based on its location:

  • Intracranial Segment:This is the segment where the ophthalmic artery originates from the internal carotid artery and runs within the cranial cavity before entering the optic canal. It is located in close relation to the optic nerve and the cavernous sinus.
  • Intraorbital Segment:After passing through the optic canal, the ophthalmic artery enters the orbit. In the intraorbital segment, it first runs inferior to the optic nerve, then crosses over it to continue medially, running alongside the medial wall of the orbit. This segment gives off multiple branches that supply the eye, extraocular muscles, lacrimal apparatus, and orbital structures.

Branches of the Ophthalmic Artery

The ophthalmic artery gives rise to numerous branches that supply the eye, orbit, and surrounding areas. These branches are divided into orbital and ocular branches:

Orbital Branches:

  • Lacrimal Artery:One of the largest branches, the lacrimal artery runs along the lateral aspect of the orbit, supplying the lacrimal gland, the conjunctiva, and the eyelids. It also gives off branches that supply the lateral rectus muscle and portions of the zygomatic area.
  • Supraorbital Artery:The supraorbital artery exits the orbit through the supraorbital foramen or notch and supplies blood to the forehead, scalp, and upper eyelid. It runs with the supraorbital nerve and provides additional supply to the frontal bone and underlying tissues.
  • Ethmoidal Arteries:The ophthalmic artery gives off the anterior and posterior ethmoidal arteries. These arteries exit the orbit through the ethmoidal foramina and supply the ethmoidal air cells, nasal cavity, and the dura mater in the anterior cranial fossa.
  • Dorsal Nasal Artery:This branch exits the orbit medially and supplies the upper part of the nose, particularly the nasal bridge and adjacent skin areas.

Ocular Branches:

  • Central Retinal Artery:One of the most important branches, the central retinal artery enters the optic nerve and travels within it to supply the inner layers of the retina. Its branches are critical for retinal nourishment and function.
  • Ciliary Arteries:The ophthalmic artery gives off several short and long posterior ciliary arteries. These arteries supply the choroid, ciliary body, and parts of the optic nerve. The long posterior ciliary arteries run forward to supply the iris and the ciliary muscle, while the short posterior ciliary arteries primarily supply the choroid.
  • Muscular Branches:The ophthalmic artery gives off several muscular branches that supply the extraocular muscles, including the superior, inferior, lateral, and medial rectus muscles, as well as the superior and inferior oblique muscles.
  • Anterior Ciliary Arteries:These arteries are branches from the muscular arteries. They follow the extraocular muscles to the anterior segment of the eye, where they help supply the conjunctiva, sclera, and cornea.
  • Palpebral Arteries:The superior and inferior palpebral arteries supply blood to the upper and lower eyelids, respectively. They contribute to the vascularization of the eyelids and conjunctiva.

Anatomical Relations

  • Optic Nerve: The ophthalmic artery is closely related to the optic nerve. After entering the orbit through the optic canal, it crosses over the optic nerve from a lateral to medial position. The central retinal artery, one of its branches, directly enters the optic nerve.
  • Orbit: The ophthalmic artery runs medially within the orbit, traveling along the medial orbital wall. It provides blood to the extraocular muscles, the lacrimal gland, the globe of the eye, and the orbital fat.
  • Ethmoidal Structures: The ethmoidal arteries branch off medially, passing through the ethmoidal foramina to supply the ethmoidal air cells and nasal cavity.

Termination

The ophthalmic artery terminates by dividing into two main branches—the dorsal nasal artery and the supratrochlear artery—which exit the orbit and supply the forehead, scalp, and the upper parts of the nose.

Function

The ophthalmic artery plays a crucial role in providing blood supply to the eye, orbit, and surrounding structures. Its numerous branches ensure the delivery of oxygenated blood to essential tissues involved in vision, eye movement, and facial sensation. Below is a detailed description of the functions supported by the ophthalmic artery.

Blood Supply to the Retina

  • Central Retinal Artery:The central retinal artery, a branch of the ophthalmic artery, supplies blood to the inner layers of the retina. This artery enters the optic nerve and travels within it to reach the retina. It provides oxygen and nutrients to the retinal ganglion cells, which are responsible for transmitting visual information to the brain via the optic nerve. The retina is highly metabolically active, and disruption of the central retinal artery’s blood flow can result in vision loss.
  • Support for Visual Function:The function of the central retinal artery is critical for visual acuity. It supplies the central portion of the retina, including the macula, which is responsible for detailed central vision. Any compromise to this artery can lead to retinal ischemia and conditions such as central retinal artery occlusion (CRAO), resulting in sudden blindness.

Blood Supply to the Choroid and Ciliary Body

  • Posterior Ciliary Arteries
    • The short and long posterior ciliary arteries, which are branches of the ophthalmic artery, supply the choroid and ciliary body. The choroid is a vascular layer of the eye that nourishes the outer retina, particularly the photoreceptors responsible for capturing light.
    • The long posterior ciliary arteries extend forward to supply the ciliary body and iris, which are involved in controlling the lens shape for accommodation (focusing) and regulating pupil size.
  • Nourishment of Photoreceptors:The posterior ciliary arteries ensure that the photoreceptors in the retina (rods and cones) receive the necessary blood supply to function correctly. These cells are responsible for capturing visual information and initiating the process of sight. Without adequate blood flow from the ciliary arteries, photoreceptors can degenerate, leading to impaired vision.

Blood Supply to the Extraocular Muscles

  • Muscular Branches:The ophthalmic artery gives off muscular branches that supply blood to the extraocular muscles, including the superior, inferior, medial, and lateral rectus muscles, as well as the superior and inferior oblique muscles. These muscles are responsible for controlling eye movement, allowing the eye to move in different directions.
  • Support for Eye Movement:By supplying the extraocular muscles, the ophthalmic artery supports the function of eye movement and coordination. This enables smooth tracking of moving objects, stabilization of the visual field, and accurate focus on visual targets. Disruption of blood supply to these muscles can result in double vision (diplopia) or strabismus (misalignment of the eyes).

Blood Supply to the Lacrimal Gland

  • Lacrimal Artery:The lacrimal artery, one of the largest branches of the ophthalmic artery, supplies the lacrimal gland, which is responsible for producing tears. The lacrimal gland plays a key role in maintaining the moisture and health of the cornea and conjunctiva by producing the aqueous component of the tear film.
  • Support for Tear Production:The blood supply provided by the lacrimal artery ensures that the lacrimal gland functions properly in tear production. Tears help lubricate the eye, protect it from foreign particles, and prevent dryness. A compromised blood supply to the lacrimal gland could lead to dry eye syndrome and an increased risk of eye infections.

Blood Supply to the Eyelids and Conjunctiva

  • Palpebral Arteries:The superior and inferior palpebral arteries are branches of the ophthalmic artery that supply blood to the upper and lower eyelids. These arteries ensure that the delicate tissues of the eyelids, including the skin, conjunctiva, and tarsal plate, receive adequate nourishment.
  • Support for Eyelid Function:The eyelids play a vital role in protecting the eye, spreading tears across the surface of the eye, and preventing damage from foreign particles. The palpebral arteries help maintain the health of the eyelid structures, ensuring proper function in blinking and eye protection.

Blood Supply to the Nasal Cavity and Forehead

  • Dorsal Nasal Artery:The dorsal nasal artery, a terminal branch of the ophthalmic artery, supplies the upper part of the nose, particularly the nasal bridge and surrounding skin. This branch plays a role in the vascularization of the nasal region, supporting the health of the nasal tissues and skin.
  • Supraorbital and Supratrochlear Arteries:The supraorbital and supratrochlear arteries are branches that exit the orbit and travel to the forehead and scalp, supplying the skin, muscles, and tissues of these regions. These arteries run alongside their corresponding nerves, ensuring that the forehead and scalp are well supplied with oxygenated blood.

Blood Supply to the Ethmoidal Sinuses and Nasal Mucosa

  • Ethmoidal Arteries (Anterior and Posterior):The anterior and posterior ethmoidal arteries branch from the ophthalmic artery and exit the orbit through the ethmoidal foramina. They supply the ethmoidal sinuses and the nasal mucosa. These structures are part of the paranasal sinuses and nasal cavity, and their proper vascular supply is essential for respiratory function and mucosal health.
  • Support for Respiratory Function:By supplying the nasal mucosa, the ethmoidal arteries contribute to the humidification and warming of inhaled air. They also support the function of the ethmoidal sinuses, which play a role in reducing the weight of the skull and enhancing vocal resonance.

Blood Supply to the Optic Nerve

  • Central Retinal Artery and Ciliary ArteriesThe central retinal artery and the posterior ciliary arteries also provide critical blood supply to the optic nerve. The optic nerve is responsible for transmitting visual information from the retina to the brain. The vascularization of the optic nerve ensures that it functions properly, supporting clear and uninterrupted transmission of visual signals.
  • Support for Visual Signal Transmission:The blood supply provided by the ophthalmic artery branches to the optic nerve helps maintain its function in transmitting visual information. Any disruption in blood flow to the optic nerve can lead to optic neuropathy, which can result in vision loss.

Clinical Significance

The ophthalmic artery is clinically significant because it is the primary source of blood supply to the eye, orbit, and surrounding structures. Any disruption in its blood flow can lead to severe vision impairment or even blindness. One of the most critical conditions associated with the ophthalmic artery is central retinal artery occlusion (CRAO), where a blockage in the central retinal artery, a branch of the ophthalmic artery, results in sudden, painless vision loss and can cause permanent blindness if not treated promptly.

Additionally, the ophthalmic artery can be involved in ischemic events such as ophthalmic artery occlusion or embolism, which can cause loss of vision, extraocular muscle dysfunction, or ischemia to the orbital and facial structures. Due to its proximity to the internal carotid artery, it may also be affected in carotid artery disease, where stenosis or plaque buildup can compromise blood flow to the ophthalmic artery and its branches.

In cases of aneurysms or tumors within the orbit or cavernous sinus, the ophthalmic artery and its branches may be compressed, leading to a variety of ophthalmic and neurological symptoms, including vision disturbances, ocular pain, and reduced eye movement. Its importance in ocular and orbital health makes the ophthalmic artery critical in the diagnosis and management of various vascular and neurological conditions.

Also Read:

  1. Anterior ethmoidal nerve
  2. Nasociliary nerve
  3. Anterior ethmoidal foramen
  4. Posterior ethmoidal nerve
  5. Superior ophthalmic vein

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  • Last updated on November 8, 2024