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PJ Penrose, A Fu, M Wang, M Menz, MD Menz, A Allen, W Fung, E Sutter; Multifocal Electroretinography (mfERG) Evaluation for Early Detection of Retinal Dysfunction in Patients Taking Hydroxychloroquine (HCQ) . Invest. Ophthalmol. Vis. Sci. 2002;43(13):1158.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To evaluate first and second order effects of mfERG in patients using HCQ. Methods: Nine patients on various daily doses (DD) and cumulative doses (CD) of HCQ were tested with a mfERG protocol and compared against nine age-matched controls. Eight of the subjects had normal clinical exam findings while one patient had bilateral central visual field defects by automated perimetry consistent with HCQ toxicity. Stimulation and analysis were performed using VERIS Science 5.0 (ElectroDiagnostic Imaging, San Mateo, CA, USA). A special stimulation mode enhancing second order effects (global flash paradigm) was used to stimulate an array of 103 densely packed hexagons covering the central 30º of the retina. Pupils were dilated and flash intensitites were 2.66 cd*sec/m2. Retinal responses were derived by means of a Burian-Allen bipolar contact lens electrode. In order to detect the loss of central retinal function characteristic of HCQ toxicity, the amplitude ratio of the central 10º to the perpheral 10-30º was estimated. Patients were evaluated using the mean and standard deviation of the control group. Results: The central to peripheral amplitude ratio of the patient with field defects (DD=6.8 mg/kg/day, CD=1025 g and ratio=1.34) and another patient with normal clinical findings (DD=5.8, CD=657 and ratio=1.71) fell below two standard deviations of the control mean (2.29, SD=0.21). The ratio in the remaining patients (DD=3.4-7.8, CD=280-1594 g and ratios=1.91-2.70) and all controls (ratios=1.82-2.52) were within two standard deviations of the mean. Conclusion: The experimental paradigm used in this small sample detected the patient with clinically evident HCQ toxicity. The paradigm was also suggestive of early central retinal dysfunction in a second, asymptomatic patient with normal clinical findings. This patient will be followed longitudinally for progression while larger cohorts of patients and controls will be evaluated to further determine the value of this mfERG test for early detection of retinal dysfunction associated with HCQ.
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