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Munir Iqbal, Wai T Wong, Emily Y Chew, Catherine A Cukras; Comparison of Choroidal and Retinal Thicknesses in Patients With and Without Hydroxychloroquine Toxicity.. Invest. Ophthalmol. Vis. Sci. 2019;60(9):5715. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Hydroxychloroquine (HCQ) has the potential to cause severe retinal dysfunction and vision loss by inducing outer retina degeneration. We evaluated choroidal and retinal thickness to detect differences between eyes affected with toxicity and unaffected eyes, both cross-sectionally and longitudinally.
Patients with a previous or current history of HCQ treatment of more than 5 years' duration were assessed with the AAO recommended testing and divided into two groups based on the presence of toxicity. Spectral domain optical coherence tomography enhanced depth imaging was obtained in all patients. Choroidal thickness was measured subfoveally (SFCT) and at 1 mm nasal and temporal to the fovea. Longitudinal analyses of tracked SD-OCT scans were performed to evaluate choroidal and retinal changes over time.
86 participants divided into affected (A) (n=36) and unaffected (UA) (n=50) groups with a mean age of 63.2±11.9 years and 56.7±12.5 years, and a mean duration on HCQ of 14.5±7.4 and 14.2±7.4 years were included in the analyses. Comparison of choroidal thickness between the affected (n = 71 eyes) and unaffected groups (n = 99 eyes) revealed no significant differences at all 3 locations assayed (SFCT median: 298±132.4μm (A) vs 289±102.4μm (UA), p=0.87). Nasal and temporal retinal thickness (1mm from fovea) were significantly thinner in the affected group than the unaffected group (nasal median: 257±39.8μm (A) vs 346±20.1μm (UA), p< 0.05; temporal median: 244±39.4μm (A) vs 327±17.6μm (UA), p<0.05).A subset of patients, affected (n=16) and unaffected (n=11), were followed longitudinally for a mean of 3.3±2.6 and 5.5±1.4 years respectively. In both groups, choroidal measurements demonstrated a trend of thinning over time. In contrast, only retinal measurements in the affected group demonstrated a small but statistically significant thinning over time with no change detected in unaffected eyes.
Eyes affected by retinal toxicity demonstrate retinal thinning that is progressive even following HCQ cessation, while eyes from unaffected participants show higher retinal thicknesses that are stable across treatment. Choroidal thicknesses do not appear to be influenced by the presence of retinal toxicity. These findings help illuminate the differential involvement of the retina and choroid in HCQ-related toxicity.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
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