Screening for Retinal Toxicity

The multifocal electroretinogram is considered to be the modern day standard in visual electrodiagnostics of central electroretinal function. The multifocal ERG (mERG) is the simultaneous recording of the central, localized electroretinal function from 61 regions of the central 60° in the posterior pole. This technology allows us to form a functional topographic map where we can assess central electrorintal function in disease states including retinitis pigmentosa, cone dystrophies, as well as assess the effect of retinal toxic medication. One area of research interest has been in applying mERG to assess early chloroquine and hydroxychloroquine toxicity in patients taking these drugs. Chloroquine (CQ) and hydroxychloroquine (HCQ) are used in the long-term treatment of rheumatic and dermatologic diseases. The prevalence of toxicity rises to 1% after 5 years of continuous treatment and greatly increases when patients have used the drug continuously for 2 decades. Early detection of CQ/HCQ retinopathy is paramount as there are no treatment options and vision loss is irreversible, and often progresses despite discontinuation of drug therapy. We are using mERG and as well as spectral domain optical coherence tomography to assess patients on long-term CQ and HCQ therapy.