Medical Retina Specialists: Screening role for Hydroxychloroquine Retinopathy
Hydroxychloroquine is used effectively in the treatment of systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA), and there is significant survival benefit of using hydroxychloroquine in patients with SLE. It has an inhibitory effect on the mechanism of cardiovascular disease i.e. thrombosis, diabetes and dyslipidaemia which can kill. It can even be used in some patients in pregnancy with SLE.
In patients with rheumatoid arthritis, Hydroxychloroquine is usually used as part of combination therapy with other antirheumatic drugs. It is largely tolerable and therefore is frequently used, a medical retinal consultant just has to be aware of the risk of retinopathy and therefore screen patients accordingly.
The annual screening criteria for patients on hydroxychloroquine includes; patients who have been on the drug for more than five years, patients who have been taking Chloroquine for more than one year, and all patients taking hydroxychloroquine who have additional risks for retinal toxicity. The final decision to screen has to be decided by the consultant medical retinal specialist. Additional risk factors for retinopathy include concomitant Tamoxifen use and impaired renal function.
At baseline examination, all retinal patients at Clinica London have colour fundus photography and spectral domain optical coherence tomography. If baseline examination demonstrates macular pathology, the baseline Humphrey 10-2 visual field test may be undertaken. The screening protocol includes telling the patient about the risks of hydroxychloroquine and providing them with written information about retinopathy and the need for screening. As well as the spectral domain optical coherence tomography SD-OCT, they require wide-field fundus autofluorescence (FAF), and if there is abnormality on the wide-field fundus autofluorescence with a normal Humphrey 10-2 visual field analysis, they should undergo a Humphrey 32 visual field testing on another date i.e. undilated.
Patients with a significant visual field defect, which is consistent with hydroxychloroquine retinopathy, but without actual structural defects on the SD-OCT or FAF, should be considered for multifocal electroretinography.
The interpretation of screening results is as follows. If there are no abnormalities suggestive of retinal toxicity or there is possible toxicity of one test result (for instance in the case of visual fields, which are reproducible and typical of hydroxychloroquine retinopathy) but without typical abnormalities on the other tests, then observed. Definite toxicity is when two test results, one subjective and one objective are found with abnormalities typical of hydroxychloroquine retinopathy.
Professor Michel Michaelides and Mr Jaheed Khan, the Medical Retinal Specialists at Clinica London can advise further if you have retinal concerns relating to the drug Hydroxychloroquine or visual symptoms from diabetes, hypertension, inherited retinal diseases or age related macular degeneration.