Background:The purpose of this study was to evaluate and compare full-field electroretinography (ERG) and multifocal electroretinography (mfERG) results in detecting retinal dysfunction in a large number of asymptomatic patients treated with hydroxychloroquine (Hy). Methods: Fifty eyes in 50 patients with rheumatic diseases who had been using Hy for a period of time ranging from 30 months to 15 years, and 25 eyes in 25 healthy controls, were evaluated. Receiver operator characteristic (ROC) curves were calculated to determine the sensitivity and specificity of abnormal values in patients compared to the normal controls. Results: Signal depression was observed on the mfERG of Hy-treated patients. The most prevalent pattern was pericentral loss (19 eyes, 54.3 per cent), followed by full-field loss (11 eyes, 31.4 per cent), and central loss (five eyes, 14.3 per cent). Conversely, depression of the amplitude responses to the full field ERG was observed in only 16 per cent of the cases. The areas under the ROC curves ranged from 0.4056 to 0.9012, with the mfERG values having the largest areas, whereas the full-field ERG curves had the smallest area. The mfERG responses yielded the greatest sensitivity and specificity. In particular, the P1-N1 wave amplitude (ring 2) and root mean square (RMS) amplitude (ring 1) had specificities of 76 and 88 per cent, respectively, at sensitivities of 90 and 86 per cent. Conclusion: A statistically significant retinal functional impairment was demonstrated by mfERG in the central two to 10 degrees in Hy-treated patients. Therefore, mfERG may provide an objective measurement of retinal dysfunction in patients receiving Hy therapy. Key words: electroretinography, hydroxychloroquine, multifocal electroretinography, retinal toxicity, rheumatic diseasesThe most common uses of hydroxychloroquine sulphate (Hy) are in the management and prophylaxis of malarial fever, rheumatoid arthritis, lupus erythematosus, Sjögren syndrome, systemic vasculitis, and mixed connective tissue disease.1-3 Hy is in a class of drugs called antimalarials and has a prolonged half-life of up to 30 days in plasma and can persist for months after therapy.3-5 Side-effects may include ocular, gastrointestinal, dermatological, auditory, cardio-circulatory, haematological and neuromuscular alterations. Hy has a high affinity for binding to melanin granules and therefore tends to accumulate in the iris, choroid, ciliary body and retinal pigment epithelium (RPE). Atrophic, pigmentary retinal changes of the periphery and the macula (bull's eye), attenuated retinal vessels and optic atrophy may be seen in rare cases of chronic retinal toxicity. The symptoms include difficulty in reading, photophobia, blurred distance vision, The purpose of this study was to investigate and compare the results of electroretinography (ERG) and mfERG in a large cohort of Hy treated patients. We also aimed to ascertain whether this relatively new test might be used as a screening examination for patients under prolonged treatment with Hy and to ...
