Branch retinal artery occlusion

Branch retinal artery occlusion (BRAO) is a medical condition characterized by the blockage of one of the smaller branches of the central retinal artery, which supplies blood to the retina. This blockage leads to a sudden, painless loss of vision in the area of the retina supplied by the affected artery.

Pathophysiology

BRAO typically occurs due to an embolism or thrombosis that obstructs the blood flow in the retinal artery. The most common sources of emboli are cholesterol plaques (Hollenhorst plaques), calcific emboli, and platelet-fibrin emboli. These emboli often originate from the carotid arteries or the heart.

Symptoms

Patients with BRAO usually experience a sudden, painless loss of vision in one eye. The extent of vision loss depends on the location and size of the occlusion. Peripheral vision may be affected if the occlusion is in a peripheral branch, while central vision may be compromised if the occlusion is in a branch supplying the central retina.

Diagnosis

Diagnosis of BRAO is primarily clinical, based on the patient's history and a thorough ophthalmic examination. Key diagnostic tools include:

• Fundoscopy: This may reveal a pale retina with a visible embolus.
• Fluorescein angiography: This imaging technique can help visualize the blood flow in the retina and identify the site of occlusion.
• Optical coherence tomography (OCT): This non-invasive imaging test provides detailed images of the retina's structure.

Management

There is no definitive treatment for BRAO, but several interventions may be attempted to improve retinal blood flow and prevent further vision loss. These include:

• Ocular massage: Gentle pressure applied to the eye to dislodge the embolus.
• Anterior chamber paracentesis: A procedure to reduce intraocular pressure.
• Hyperbaric oxygen therapy: To increase oxygen delivery to the retina.

Prognosis

The prognosis for BRAO varies. Some patients may experience partial recovery of vision, while others may have permanent vision loss. The outcome largely depends on the duration of the occlusion and the promptness of intervention.

Prevention

Preventive measures focus on managing risk factors for embolism, such as:

• Controlling hypertension
• Managing diabetes mellitus
• Lowering cholesterol levels
• Treating underlying cardiovascular disease

See also

• Central retinal artery occlusion
• Retinal vein occlusion
• Amaurosis fugax
• Ophthalmology