Infectious Retinitis

Infectious retinitis is a serious condition in which an infection causes inflammation and damage to the retina. The retina is the light-sensitive tissue at the back of the eye that is responsible for vision.

Many different infections can affect the retina, including viruses, bacteria, fungi, and parasites. Infectious retinitis can progress rapidly and may lead to permanent vision loss if not diagnosed and treated promptly.

Because this condition can threaten vision quickly, infectious retinitis is considered an ophthalmic emergency.

What Causes Infectious Retinitis?

Infectious retinitis occurs when microorganisms invade the retina and cause inflammation.

Common causes include:

Viral Infections

Viruses are among the most common causes of infectious retinitis.

Examples include:

Cytomegalovirus (CMV)
Herpes simplex virus (HSV)
Varicella zoster virus (VZV), which causes shingles

Bacterial Infections

Bacterial infections may occur from:

Syphilis
Tuberculosis
Bartonella (cat scratch disease)
Lyme disease

Fungal Infections

Fungal infections are less common but can occur in patients with weakened immune systems or bloodstream infections.

Parasitic Infections

Toxoplasmosis is one of the most common parasitic retinal infections worldwide.

Who Is at Risk?

Certain individuals are at higher risk for infectious retinitis, including:

Patients with weakened immune systems
Individuals with HIV/AIDS
Organ transplant recipients
Patients receiving chemotherapy or immunosuppressive medications
Individuals with uncontrolled diabetes
Patients with systemic infections

However, infectious retinitis can also occur in otherwise healthy individuals.

Symptoms of Infectious Retinitis

Symptoms may develop suddenly and often worsen quickly.

Common symptoms include:

Blurred vision
Floaters
Flashes of light
Eye redness
Eye pain
Sensitivity to light
Dark spots or blind spots in vision
Sudden vision loss

Symptoms may affect one or both eyes depending on the infection.

Some infections, such as acute retinal necrosis, can progress very rapidly and cause severe retinal damage within days.

Common Types of Infectious Retinitis

Cytomegalovirus (CMV) Retinitis

CMV retinitis most commonly occurs in patients with severely weakened immune systems, especially advanced HIV infection.

It may cause:

Floaters
Blurry vision
Retinal bleeding
Progressive vision loss

Without treatment, CMV retinitis can lead to retinal detachment and blindness.

Acute Retinal Necrosis (ARN)

ARN is usually caused by herpes viruses and can affect healthy individuals.

This condition often causes:

Severe inflammation
Pain
Retinal destruction
Retinal detachment

Prompt treatment is critical.

Ocular Toxoplasmosis

Toxoplasmosis causes inflammatory retinal scars and active retinal infection.

Patients may experience:

Floaters
Blurred vision
Recurrent episodes of inflammation

How Is Infectious Retinitis Diagnosed?

A retinal specialist diagnoses infectious retinitis through a detailed eye examination and specialized testing.

Dilated Eye Examination

The retina may show:

White retinal lesions
Bleeding
Inflammation
Retinal necrosis
Vitreous inflammation

Optical Coherence Tomography (OCT)

OCT helps evaluate retinal swelling and retinal damage.

Fluorescein Angiography

This imaging test evaluates retinal blood vessels and areas of inflammation or poor blood flow.

Laboratory Testing

Blood tests, imaging, or samples of fluid from inside the eye may help identify the specific infection.

Early diagnosis is extremely important because different infections require different treatments.

Treatment for Infectious Retinitis

Treatment depends on the specific organism causing infection.

Antiviral Medications

Viral infections may require:

Oral antiviral medications
Intravenous antiviral therapy
Antiviral injections into the eye

Antibiotics

Bacterial infections are treated with targeted antibiotics.

Antifungal Medications

Fungal infections require antifungal medications, sometimes including injections directly into the eye.

Anti-Parasitic Therapy

Toxoplasmosis may be treated with combinations of anti-parasitic and anti-inflammatory medications.

Steroid Medications

Steroids may sometimes help reduce inflammation, but they must be used carefully and usually only after infection treatment has begun.

Surgery

Vitrectomy surgery may be needed if:

Severe inflammation develops
Retinal detachment occurs
Bleeding blocks vision

What Is the Prognosis?

Visual outcomes depend on:

The type of infection
How quickly treatment begins
The location of retinal damage
The patient’s immune system

Some patients recover useful vision, while others may experience permanent retinal scarring and vision loss.

Prompt diagnosis and treatment greatly improve the chance of preserving vision.

Living With Infectious Retinitis

Patients with infectious retinitis should:

Keep all follow-up appointments
Take medications exactly as prescribed
Report worsening symptoms immediately
Work closely with both eye doctors and primary care physicians
Maintain management of underlying medical conditions

Patients with immune system disorders may require long-term monitoring.

Frequently Asked Questions

Is infectious retinitis contagious?

The retinal infection itself is not usually spread directly from person to person through eye contact. However, some underlying infections may be contagious in other ways.

Can infectious retinitis cause blindness?

Yes. Without prompt treatment, infectious retinitis can lead to permanent vision loss or blindness.

How quickly should treatment begin?

Treatment should begin as soon as possible because some forms of infectious retinitis can progress rapidly and permanently damage the retina.

More Information

For additional patient information, visit the American Society of Retina Specialists Infectious Retinitis Fact Sheet