Abstract
Purpose :
Hydroxychloroquine (HCQ) retinopathy is known to progress after drug cessation, but no studies have described serial changes beyond about three years. Cases without retinal pigment epithelium (RPE) damage appear to stabilize, while those with RPE damage progress. However, it remains unclear whether this stability lasts, or whether progression eventually stabilizes. To answer these questions, we have reviewed the course of HCQ retinopathy over longer periods of time.
Methods :
This is a retrospective review of findings from thirteen patients with HCQ retinopathy classified as early (patchy parafoveal damage, n=3), moderate (ring of photoreceptor thinning without RPE damage, n=2), or severe (visible Bull’s eye maculopathy, n=8). Patients had been off HCQ for up to 240 months at initial examination, and were then followed for up to 93 months. We used fundus autofluorescence (FAF) images to measure RPE damage, and spectral domain optical coherence tomography (SD-OCT) to measure outer nuclear layer thickness (ONL) and length of the ellipsoid zone (EZ) line.
Results :
During the follow up period, early and moderate cases demonstrated mild parafoveal thinning in the first 1-2 years after stopping HCQ, but stable foveal thickness and EZ line length thereafter for as much as 8 years. In contrast, the severe cases (including one who stopped the drug 20 years previously) demonstrated continued progression of foveal thinning and/or EZ line loss throughout the period of follow-up (roughly 6 years or more). The central ONL and EZ line disappeared in several cases.
Conclusions :
We have roughly doubled the length of observation for retinopathy patients who have stopped HCQ. Patients with mild retinopathy showed complete stability for many years. In contrast, patients with RPE damage worsened steadily for many years, and some lost the fovea. It remains unclear whether this process can stop before reaching an end stage. While these findings are disappointing with respect to prognosis, they stress the importance of early detection of HCQ toxicity to minimize progression and visual loss. They also raise questions about how progression occurs long after HCQ drug reservoirs should have been depleted. This may relate to irreversible metabolic compromise of the RPE, since RPE damage seems a prerequisite, so that early intervention with RPE transplantation, stem cell therapy or anti-apoptotic drugs may be of value in the future.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.