Abstract
Purpose :
Hydroxychloroquine (HCQ), which is used to treat autoimmune diseases, can cause retinal toxicity which manifests photoreceptor loss and damage to the retinal pigment epithelium (RPE), ultimately leading to irrecoverable central vision loss. Structural evidence of retinal toxicity is provided by disruption of the ellipsoid zone (EZ) reflectivity band and change in outer retina thickness (ORT), both of which are detectable on spectral-domain optical coherence tomography (SD-OCT) imaging and display different patterns based on various demographic characteristics. This work investigates spatial differences in retinal susceptibility to these changes to better understand and detect retinal toxicity after HCQ treatment.
Methods :
87 patients (average age, 58.8±12.1 years) on long-term HCQ (14.1±7.3 years) enrolled in a case-control study (NCT01145196) underwent imaging with SD-OCT (Heidelberg Spectralis). Of the 32 patients who demonstrated evidence of toxicity, 20 were White, 6 were Black, 3 were Asian, and 3 were of unknown race. 2D enface maps of EZ loss and ORT were generated with automated algorithms and analyzed within each eye relative to the fovea location and demographic data, including race and ethnicity.
Results :
In eyes without foveal involvement, the pattern of EZ loss demonstrated that the location of EZ loss closest to the fovea occurred most commonly in the inferotemporal sector (17/30). Eyes had a range of EZ loss areas and patterns (EZ loss area, Asian=29.88±21.48 mm2, Black=21.60±16.35 mm2, Caucasian=9.23±9.43 mm2, p=0.000254). For eyes without foveal involvement (EZ loss>250 μm from the fovea), areas of EZ loss were greater in Black and Asian eyes. For eyes with large amounts of EZ loss (>20 mm2), more Asian and Black eyes (6/8) maintained EZ loss further from the fovea (>250 μm). Analyses of ORT in the foveal B scans revealed the differences between affected and unaffected eyes to occur further from the fovea in Black and Asian affected eyes than in Caucasian eyes.
Conclusions :
Quantitative analyses of structural changes in HCQ toxicity can reveal differences in retina spatial involvement within an eye and between patients. Causes for differential involvement may be due to gradients within the retina and differences in cellular distributions between patients which may be affected by race. This has implications for screening participants as well as for the development of interventions.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.