Chloroquine retinopathy

A condition caused by the use of chloroquine, affecting the retina of the eye

Chloroquine retinopathy

Fundus photograph showing changes in the retina due to chloroquine retinopathy

Chloroquine retinopathy, also known as hydroxychloroquine retinopathy, is a retinal disorder caused by the use of the antimalarial drugs chloroquine and hydroxychloroquine. These medications are commonly used in the treatment of rheumatoid arthritis, systemic lupus erythematosus, and other autoimmune diseases. The condition is characterized by damage to the retina, particularly the macula, which can lead to vision loss if not detected early.

Pathophysiology

Chloroquine and hydroxychloroquine are known to bind to melanin in the retinal pigment epithelium (RPE), leading to toxic effects on the retina. The accumulation of these drugs in the RPE can cause damage to the photoreceptor cells and the RPE itself, resulting in the characteristic "bull's-eye" maculopathy seen in advanced cases.

Clinical features

Patients with chloroquine retinopathy may initially be asymptomatic. As the condition progresses, they may experience symptoms such as:

• Blurred vision
• Difficulty reading
• Decreased color vision
• Paracentral scotomas (blind spots)

The classic "bull's-eye" maculopathy is a late finding and indicates significant retinal damage.

Diagnosis

The diagnosis of chloroquine retinopathy is primarily clinical, supported by various imaging techniques. These include:

• Fundus photography: To document changes in the retina.
• Optical coherence tomography (OCT): To detect early structural changes in the retina.
• Visual field testing: To identify functional deficits.
• Fundus autofluorescence: To detect early RPE damage.
• Multifocal electroretinography (mfERG): To assess retinal function.

Management

The primary management strategy for chloroquine retinopathy is the early detection and cessation of the offending drug. Once significant retinal damage has occurred, it is often irreversible. Regular screening is recommended for patients on long-term chloroquine or hydroxychloroquine therapy to detect early signs of retinopathy.

Prevention

Preventive measures include:

• Baseline ophthalmologic examination before starting therapy.
• Regular follow-up examinations, typically annually, after five years of therapy or sooner if risk factors are present.
• Dose adjustment based on ideal body weight to minimize risk.

Prognosis

The prognosis of chloroquine retinopathy depends on the stage at which it is detected. Early detection and drug cessation can prevent progression and preserve vision. However, once advanced retinopathy has developed, the visual prognosis is poor.

Related pages

• Retinal disease
• Maculopathy
• Antimalarial drugs