How to screen asymptomatic patients taking HCQ

A 65-year-old obese man with systemic lupus erythematosus presents to the ophthalmology clinic, referred from rheumatology for "toxicity screening" after starting therapy with hydroxychloroquine sulfate (HCQ) 400 mg per day (Plaquenil Sulfate). He had prior lupus-related glomerulonephritis but has a stable serum creatinine level. There was no liver dysfunction.

The ocular exam shows 20/20 visual acuity OU but the fundus exam shows a few macular drusen and a few retinal pigment epithelial changes in the macula OU. What visual field test should be performed? Are there any additional tests that are indicated for the screening exam? When should the patient return for follow-up?

In contrast to the AAO guidelines, in the United Kingdom, the Royal College of Ophthalmologists, the British Association of Dermatologists, and the British Society for Rheumatology recommend the following:

2) Inquiry about visual symptoms and recording of near visual acuity at baseline exam.

3) Inquiry about visual symptoms at each visit and measurement of visual acuity annually.

4) Referral to an ophthalmologist for patients with ocular disease at baseline or for those who develop visual symptoms on treatment. Indeed in the UK, some authors have suggested that a baseline eye exam and regular ophthalmologic screening may not be required at all in low-risk patients taking low (<6.5 mg/kg) doses of HCQ.⁷

Case discussion Our patient is older than 60 years and is obese, but has concomitant renal dysfunction and pre-existing macular pathology.