J Retin.  2024 May;9(1):62-72. 10.21561/jor.2024.9.1.62.

Longitudinal Changes in Outer Nuclear Layer and Choroidal Thickness in Patients Using Hydroxychloroquine Before Retinopathy

• Min CH
• Jo J
• Lee JY
• Yoon YH

• KMID: 2556468
• DOI: http://doi.org/10.21561/jor.2024.9.1.62

Abstract

Purpose
Early detection of hydroxychloroquine (HCQ)-related retinopathy is important. We aimed to determine whether changes in choroidal thickness (ChT) and outer nuclear layer (ONL) thickness might signal impending HCQ toxicity before development of retinopathy.
Methods
We included patients with systemic lupus erythematosus or rheumatoid arthritis who were treated with HCQ and followed for ≥ 12 months. Patients were categorized into groups with no HCQ-related retinopathy (HCQ continued (group A, n = 49) or HCQ discontinued (group B, n = 9) and with HCQ-related retinopathy (group C, n = 9) groups. Using optical coherence tomography (OCT) images, ChT measurements were obtained at the subfovea and 1.5 mm nasal and temporal to the fovea. ONL thickness was obtained from the fovea using inner and outer rings of the Early Treatment of Diabetic Retinopathy Study (ETDRS) grid.
Results
At baseline, mean ChT was thinner in all of the HCQ intake groups than in normal eyes (n = 35). Among patients with no retinopathy, ChT at all measured locations decreased in group A (average ChT, p < 0.001), whereas the average ChT significantly improved in group B after HCQ discontinuation (p = 0.038). In all HCQ groups, ONL thicknesses in the outer ETDRS ring area continued to show a significant decrease during follow-up, regardless of HCQ continuity (p ≤ 0.050). The association between an average of the outer ETDRS ONL thickness and ChT changes in group A was also statistically significant after adjusting for daily dose per kg and duration of HCQ use (p = 0.042).
Conclusions
Among patients without HCQ-related retinopathy, ChT continued to decrease during HCQ treatment but stopped thinning and was partially recovered following HCQ discontinuation. ONL thinning was observed progressively regardless of HCQ continuity. ChT and ONL measurements might be used for early detection of HCQ retinal toxicity.

Keyword

Choroid; Hydroxychloroquine retinopathy; Optical coherence tomography; Outer nuclear layer thickness