What vision testing is recommended for patients taking Plaquenil (hydroxychloroquine)?

Vision Testing Recommendations for Patients Taking Plaquenil (Hydroxychloroquine)

For patients taking hydroxychloroquine (Plaquenil), baseline ocular examination should be performed within the first year of use, followed by annual screening after 5 years of treatment for low-risk patients, with more frequent monitoring for high-risk individuals. 1

Baseline Examination

A comprehensive baseline ocular examination should be conducted within the first year of starting hydroxychloroquine therapy and should include:

1. Best corrected visual acuity (Snellen chart) 1, 2
2. Automated threshold visual field testing 1, 2
   • 10-2 pattern for non-Asian patients
   • 24-2 or 30-2 pattern for Asian patients (who often show toxicity beyond the macula) 1
3. Spectral domain optical coherence tomography (SD-OCT) 1, 2
4. Color discrimination testing (Ishihara tests) 1
5. Fundus examination to rule out pre-existing maculopathy 1

Ongoing Monitoring Schedule

Standard Risk Patients:

• Begin annual screening after 5 years of hydroxychloroquine use 1, 2
• Annual examinations include the same tests performed at baseline

High-Risk Patients:

More frequent monitoring (every 6-12 months) is recommended for patients with the following risk factors:

• Daily dosage >5.0 mg/kg of real body weight 1, 2
• Treatment duration >5 years 1, 2
• Renal disease (decreased glomerular filtration rate) 1, 3
• Concomitant tamoxifen use 1, 3
• Pre-existing macular disease 1
• Age >65 years 4
• Liver disease 2

Pediatric Patients

For pediatric patients, annual retinal screening is recommended from the start of treatment rather than waiting 5 years between baseline and subsequent screenings as recommended for adults 1. This is because:

1. Children may receive treatment for prolonged periods
2. Children may not be able to articulate vision concerns
3. Developmental effects of hydroxychloroquine are a concern 1

Recommended Testing Procedures

Primary Screening Tests:

1. Automated visual fields 1

   • White SITA testing with pattern deviation plots
   • 10-2 pattern for non-Asian patients
   • 24-2 or 30-2 pattern for Asian patients

2. Spectral domain OCT 1

   • Objective test that is highly specific
   • Can detect retinal changes before visible damage occurs

Additional/Confirmatory Tests:

• Multifocal electroretinogram (mfERG) - provides objective corroboration for visual fields 1, 5
• Fundus autofluorescence (FAF) - can show damage topographically 1

Patient Education and Monitoring

• Patients should be questioned at each visit about visual disturbances including blurred vision or scotomata 1
• Instruct patients to contact their physician immediately if they experience any change in vision 1
• Check dosage relative to weight at every visit 1
• Ask about changes in systemic status such as weight loss, kidney disease, or tamoxifen use 1

Important Considerations

When to Discontinue Medication

Hydroxychloroquine should be discontinued immediately and permanently if there are any signs of visual toxicity 1. Early detection is crucial because:

• Retinopathy is not reversible 1
• When recognized early (before RPE damage), there is only mild and limited progression after discontinuation 1
• When detected late (bull's-eye retinopathy), damage can progress for years with eventual loss of visual acuity 1

Common Pitfalls to Avoid

1. Relying solely on fundus examination - modern screening should detect retinopathy before it is visible in the fundus 1
2. Using inappropriate visual field patterns - using 10-2 fields for Asian patients may miss peripheral toxicity 1
3. Stopping medication based on uncertain findings - confirm suspicious findings with more than one test or repeat testing 1
4. Delaying initial screening - baseline examination should be performed within the first year of use 1, 2
5. Ignoring patient-reported visual changes - any reported visual changes should prompt immediate evaluation 1

By following these recommendations, clinicians can help prevent serious retinal damage while allowing patients to continue beneficial hydroxychloroquine therapy when appropriate.