Abstract
Purpose:
Hydroxychloroquine (HCQ) is an analogue of chloroquine with well-documented toxic effects on the retina. In addition to its anti-malarial use, HCQ is commonly used in the treatment of systemic lupus erythematosus, rheumatoid arthritis, and other connective tissue disorders. There have been several reports of progression of retinal toxicity after cessation of the medication. In this study, we use multifocal electroretinography (mfERG) to illustrate both improvement and progression of retinal function in patients with toxicity who stopped taking HCQ.
Methods:
A retrospective review of 23 patients with HCQ retinal toxicity were followed for an average of nearly two years after discontinuing the medication. Clinical examinations including both visual fields and mfERGs were done. Evaluation of mfERG ring ratio patterns of 26 patients taking HCQ with no evidence of toxicity was used to establish a normal baseline variation. Following cessation of HCQ, multiple variables were evaluated to identify changes in retinal toxicity including changes in mfERG ring ratio, visual field, visual acuity, and fundus examination.
Results:
Of the 23 patients with HCQ retinal toxicity included in this study the median patient age was 57 years (range 31-82). All patients were female. The average follow-up was 23 months (range 3.5-78). The average cumulative dose of HCQ was 2147 grams (range 1015-3625). Using mfERG ring ratio evaluation, 8/23 (34.8%) worsened, 9/23 (39.1%) had no change, and 6/23 (26.1%) showed improvement during the follow-up period. The initial degree of central involvement was more apparent in the group with a worsening ring ratio pattern. There was no statistically significant difference in the cumulative dose of HCQ or change in visual acuity across these three groups. Follow-up Humphrey visual field testing showed only a 50% correlation in detection of changes found on mfERG.
Conclusions:
Previous studies have shown the value of using mfERG to screen and monitor patients taking HCQ. This study shows that a significant proportion of patients have at least modest improvement in function as measured by the mfERG ring ratio after cessation of HCQ. No previous studies have shown evidence of functional improvement by this measure after cessation of HCQ therapy.
Keywords: 688 retina •
503 drug toxicity/drug effects •
509 electroretinography: clinical