Evaluation of optical coherence tomography angiography parameters in patients treated with hydroxychloroquine

Abstract

Background One of the major side effects of hydroxychloroquine is retinopathy. The aim of this study was to evaluate the Optical coherence tomography angiography (OCTA) parameters in a group of patients who have hydroxychloroquine-induced retinopathy based on Multifocal electroretinography (mfERG) with a group who do not have retinopathy.Method This is a Cross-Sectional Study. In this study, patients with RA or SLE who had been taking HCQ for at least 7 years were included. MfERG and OCTA imaging were performed for all patients. Patients were divided into Normal mfERG and Abnormal mfERG groups based on mfERG results. OCTA parameters were studied in these two groups.Result 61 patients (61 eyes) were included. 41 patients had SLE and 20 patients had RA. 40 patients (66.7%) had Abnormal mfERG. The mean VD in SCP layer was not significantly different between Normal mfERG and Abnormal mfERG groups (P-Value> 0.05). Mean VD in SCP layer was not significantly different between Normal mfERG and Abnormal mfERG groups (P-Value> 0.05). In RA subgroup, mean VD in SCP layer in PeriFovea region in Abnormal mfERG group was significantly lower than normal group (P-Value <0.05). Mean VD in DCP layer in Whole Image, Superior Hemi, Inferior Hemi, PeriFovea area in Abnormal mfERG group was significantly lower than normal group (P-Value <0.05). This discrepancy was also observed in the RA subgroup but not in the SLE subgroup. The mean of none of the parameters of FAZ (mm2), Flow Area of Outer Retina (mm2) and Flow Area of Choriocapillaris (mm2) were not statistically significant between the groups Abnormal mfERG and Normal mfERG. (p-value>0.05). Conclusion VD in the DCP layer decreased in abnormal mfERG patients compared to patients with normal mfERG. But it seems that VD in SCP layer, FAZ Area and Flow Area are similar in both groups. OCTA may be used as a non-invasive tool in the diagnosis of early stages of HCQ-induced retinopathy, especially in RA patients, but further studies are needed.

New insights in pathogenic mechanism of hydroxychloroquine retinal toxicity through optical coherence tomography angiography analysis

“…Nevertheless, the diagnosis of HCQ retinopathy should be made conclusively, as cessation of treatment can lead to reactivation of systemic disease. 1,3,5 The American Academy of Ophthalmology (AAO) published recommendations for screening of HCQ retinopathy in 2016. The patients should be screened at the start of medication and annually after 5 years of treatment.…”

“…These results agree with previous research. 1,3,4,6,11,13,18,22,23 It is known that tall RPE cells with increased melanin contribute to the formation of FAZ. We suggest that the binding of HCQ to melanin of RPE cells may enlarge the FAZ area.…”

“…Nonetheless, retinal toxicity is a major and potentially irreversible side effect of this drug, occurring in approximately 6% of patients receiving HCQ therapy for more than 5 years. 1–5…”

“…Risk factors associated with the development of HCQ retinopathy include daily dose greater than 5 mg/kg, cumulative dose greater than 1000 g, duration of use over 5 years, elderly age, kidney or liver dysfunction, preexisting maculopathy or concomitant use of tamoxifen. 1,6–8…”

“…Nonetheless, retinal toxicity is a major and potentially irreversible side effect of this drug, occurring in approximately 6% of patients receiving HCQ therapy for more than 5 years. [1][2][3][4][5] The mechanism of retinal toxicity is not well understood. HCQ is likely to bind to melanin within retinal pigment epithelium (RPE) and choroid, which are melaninrich ocular tissues.…”