Detection of Hydroxychloroquine toxicity based on AAO 2016 Guidelines

Abstract

Purpose : The 2016 guidelines by the American Academy of Ophthalmology (AAO) on screening for Hydroxychloroquine (HCQ) retinopathy (HCQR) recommend the use of ancillary testing, including Fundus Autofluorescence (FAF) and multifocal electroretinography (mfERG), in addition to the standard use of the clinical exam, visual fields and optical coherence tomography (OCT). At recommended HCQ doses, the risk of toxicity up to 5 years is under 1% and up to 10 years is under 2%, but after 20 years it rises to almost 20%. Next generation ancillary testing modalities may improve sensitivity to detect toxicity. The objective of this study is to estimate the prevalence of HCQ related abnormalities on using the 2016 AAO recommendations on ancillary testing.

Methods : Microperimetry (MP) was used as a substitute for Humphrey Visual Fields (HVF). Ophthalmic exam, MP, OCT, FAF, mfERG were performed on 443 eyes of 222 patients who met the Systemic Lupus International Collaborating Clinics (SLICC) criteria for diagnosing Systemic Lupus Erythematosus (SLE) and were using HCQ. Ophthalmic examinations and testing were interpreted by trained investigators.

Results : The mean duration of treatment with HCQ was 12.5 years in 222 consecutive SLE patients (443 eyes) on whom all four tests were performed. 103 eyes (23 %) had abnormal findings on OCT with 47 (11 %) of them being HCQ related. 121 eyes (27 %) had abnormal findings on MP with 30 (7 %) of them being HCQ related. FAF yielded abnormal findings in 106 eyes (24 %) with 26 (6 %) of them related to HCQ toxicity. For mfERG, 129 eyes (29 %) had abnormal findings with 24 (5 %) of them consistent with HCQ toxicity. Overall, 47 (11 %) eyes were rated as HCQ-related abnormalities on OCT, 30 (7 %) on MP, 26 (6 %) on FAF and 24 (5 %) on mfERG. 32 eyes (7%) demonstrated changes consistent with HCQ retinopathy in two or more tests and 11 eyes (2%) did so in all four tests.

Conclusions : Our findings indicate that ancillary testing shows high sensitivity of HCQR. OCT showed the highest sensitivity in terms of abnormalities, though half of those were not related to HCQ toxicity, demonstrating relatively low specificity. MP, FAF and mfERG may contribute critical additional information for making a decision to continue or stop HCQ in such cases.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.