Plaquenil Eye Exam: AAO Screening
Master the plaquenil eye exam for NBEO and OKAP: dosing, screening intervals, OCT, visual fields and Asian pericentral toxicity.
Hydroxychloroquine retinal toxicity screening relies primarily on which imaging finding pattern in early stages?
Plaquenil Eye Exam in 30 Seconds
A plaquenil, or hydroxychloroquine, eye examination screens for retinal toxicity before irreversible central vision loss develops. Toxicity is irreversible and may progress after the drug is stopped. The goal is to detect early functional or structural change before advanced macular damage develops.
Why Hydroxychloroquine Damages the Retina
Hydroxychloroquine accumulates within melanin-containing retinal pigment epithelial cells, leading to progressive photoreceptor and RPE dysfunction. Most patients show parafoveal toxicity, with bull's-eye maculopathy in advanced cases. Asian patients more often show a pericentral pattern. Toxicity is typically bilateral and symmetric, is irreversible, and can progress after drug cessation.
Screening Guidelines (AAO 2016)
- Daily dose greater than 5 mg/kg of real body weight is a major risk factor. Use real body weight for NBEO and OKAP dosing questions.
- At recommended doses, risk remains low during the first 5 years but increases substantially thereafter. Duration determines when routine annual screening begins.
- Renal disease, tamoxifen use and pre-existing retinal disease increase risk. Added risks warrant closer attention before the 5-year mark.
- Obtain a baseline examination within the first year of treatment. Baseline testing primarily excludes pre-existing maculopathy.
- Start annual screening after 5 years for patients without added risk factors. Earlier annual screening is appropriate when major risks exist.
Recommended Screening Tests
- Automated visual fields: 10-2 in most patients, 24-2 or wider in Asian patients. Detects characteristic parafoveal or pericentral functional loss.
- Spectral-domain OCT evaluates parafoveal thinning and ellipsoid zone loss. It is a primary structural screening test.
- Fundus autofluorescence demonstrates parafoveal or pericentral RPE abnormalities and complements OCT. It supports topographic assessment of toxicity.
- Multifocal ERG is an objective functional test when available. It can corroborate suspected toxicity.
- Fundus examination and color vision are insufficient for early detection. A normal appearance does not exclude early retinal toxicity.
4 Facts Exams Always Ask
- The key threshold is greater than 5 mg/kg/day using real body weight, with risk increasing substantially after 5 years.
- The two primary screening tests are automated visual fields and spectral-domain OCT.
- Asian patients may have pericentral toxicity, so use 24-2 or wider visual field testing.
- Toxicity is irreversible and may continue to progress after hydroxychloroquine is stopped.
The Classic Trap
Do not rely on a normal fundus examination or wait for bull's-eye maculopathy. Bull's-eye change is late toxicity and should never be the goal of screening. Modern screening aims to detect preclinical toxicity before visible fundus changes develop, using visual fields and OCT. In the 2016 guidelines, the dose threshold uses real body weight, not ideal body weight.
Clinical Pearl
Remember 5 mg/kg/day of real body weight. Screen Asian patients with wider fields because toxicity may be pericentral rather than parafoveal. Detect toxicity before RPE damage develops, because a visible bull's-eye maculopathy indicates advanced and irreversible injury. Once definite toxicity is detected, prompt communication with the prescribing physician is recommended to discuss the risks and benefits of continuing hydroxychloroquine.
Checkpoint 1
According to the 2016 AAO screening guidelines, which daily dose threshold defines a major risk factor for hydroxychloroquine retinal toxicity?
Checkpoint 2
Why should patients of Asian descent on hydroxychloroquine be screened with a 24-2 or wider visual field rather than 10-2 alone?
A 54-year-old woman with lupus has taken hydroxychloroquine for 7 years. Her dose is 6 mg/kg/day based on real body weight. She has no visual symptoms and a normal fundus examination. OCT shows subtle parafoveal ellipsoid zone loss, while a 10-2 field shows matching parafoveal defects. Which imaging finding represents the earliest and most sensitive indicator of toxicity in such patients?
For patients on long-term hydroxychloroquine therapy, which imaging finding represents the earliest and most sensitive indicator of toxic maculopathy, often preceding visual field or fundus changes?
Sources & Publisher Info
References
- American Academy of Ophthalmology. Recommendations on Screening for Chloroquine and Hydroxychloroquine Retinopathy: 2016 Revision.
- American Academy of Ophthalmology. BCSC Section 12: Retina and Vitreous.
- American Academy of Ophthalmology. EyeWiki: Hydroxychloroquine Toxicity.
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