Effect of Disease Stage on Progression of Hydroxychloroquine Retinopathy

Abstract

The potential for chloroquine phosphate and hydroxychloroquine sulfate retinopathy to progress after cessation of the drug has long been recognized,^1-4 primarily in patients with severe ring scotoma or a visible bull’s-eye lesion in the fundus. Such progression could continue for many years after the drug was stopped. Some of the early studies also suggested^1,2,4 that early or mild disease does not advance after the drug is discontinued. Kellner et al⁵ reported a small series of retinopathy cases in which all those with severe damage progressed over a period of years in contrast to one with minimal fundus autofluorescence (FAF) changes. The progression of retinopathy had been measured traditionally by subjective field testing and relatively insensitive fundus examination. The development of multifocal electroretinography more than 15 years ago introduced an objective test for field measurement. However, multifocal electroretinography has considerable variability and technical challenges that have limited its use and made it poorly suited for monitoring subtle changes over time. Modern spectral density–optical coherence tomography (SD-OCT) provides a critical objective tool for grading severity and judging progression in early cases of retinopathy.