Retinal edema

Retinal Edema

Retinal edema, also known as macular edema when it affects the macula, is a condition characterized by the accumulation of fluid in the retinal layers of the eye. This fluid buildup leads to swelling and can significantly impair vision. Retinal edema is often associated with various ocular and systemic conditions, most notably diabetic retinopathy and retinal vein occlusion.

Pathophysiology

The retina is a thin layer of tissue lining the back of the eye, responsible for converting light into neural signals that are sent to the brain. Retinal edema occurs when the blood-retinal barrier is disrupted, allowing fluid to leak from the retinal blood vessels into the interstitial space. This leakage can be due to:

• Increased vascular permeability: Often caused by inflammatory mediators such as vascular endothelial growth factor (VEGF).
• Vascular occlusion: Blockage of retinal veins can lead to increased hydrostatic pressure and fluid leakage.
• Diabetes mellitus: Chronic hyperglycemia can damage retinal blood vessels, leading to diabetic macular edema.

Clinical Presentation

Patients with retinal edema may experience:

• Blurred or distorted vision
• Difficulty reading or recognizing faces
• Dark or empty areas in the center of vision
• Colors appearing washed out or different

The severity of symptoms often correlates with the extent and location of the edema.

Diagnosis

Diagnosis of retinal edema typically involves:

• Ophthalmoscopy: Direct visualization of the retina to assess swelling and other changes.
• Optical coherence tomography (OCT): A non-invasive imaging test that provides cross-sectional images of the retina, allowing for detailed assessment of retinal thickness and fluid accumulation.
• Fluorescein angiography: An imaging technique that uses a fluorescent dye to highlight blood vessels in the retina, helping to identify areas of leakage.

Treatment

Treatment of retinal edema depends on the underlying cause and may include:

• Anti-VEGF therapy: Intravitreal injections of anti-VEGF agents (e.g., ranibizumab, aflibercept) to reduce vascular permeability and edema.
• Corticosteroids: Intravitreal or periocular injections to reduce inflammation and fluid accumulation.
• Laser photocoagulation: Focal or grid laser treatment to seal leaking blood vessels and reduce edema.
• Surgical intervention: In cases of severe or persistent edema, vitrectomy may be considered.

Prognosis

The prognosis for retinal edema varies depending on the cause and the timeliness of treatment. Early detection and management are crucial for preserving vision. Chronic or untreated edema can lead to permanent vision loss.

Also see

• Diabetic retinopathy
• Macular degeneration
• Retinal vein occlusion
• Optical coherence tomography