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Raul Fernando Membreno, Tharindu de silva, Tiarnan D L Keenan, Henry Wiley, Wai T. Wong, Emily Chew, Catherine A Cukras; Quantitative Analysis of Optical Coherence Tomography Scans in Patients with Hydroxychloroquine Toxicity. Invest. Ophthalmol. Vis. Sci. 2020;61(7):4287.
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Hydroxychloroquine (HCQ) is a first-line treatment for many autoimmune diseases but causes retinopathy in some long-term users. We explored how OCT imaging may aid detection of retinopathy in patients by quantitative comparisons between affected and unaffected patients.
87 subjects exposed to HCQ for >5-year duration were classified into affected (N=32) and unaffected (N=55) cohorts using multi-modal screening tests, including multifocal ERG. For affected eyes, foveal horizontal and vertical OCT scans were graded using the following severity scale: stage 1- <100 mm disruption in ellipsoid zone (EZ), stage 2- EZ loss of 100 mm to 1 mm, stage 3- EZ loss >1 mm, and stage 4- <500 mm of a foveal island of EZ remaining. For all eyes, central macular scans were segmented into inner (ILM to OPL) and outer (OPL to RPE) layers; mean thicknesses and mean signal intensities for each layer in each of the 9 ETDRS subfields were computed and compared.
In affected eyes, severity grading for horizontal scans were: 16/64 (25%) as stage 1, 7/64 (11%) as stage 2, 28/64 (44%) as stage 3, and 13/64 (20%) as stage 4. The majority 40/64 (63%) had agreement between vertical and horizontal grades. Comparing all affected and unaffected eyes, total retinal thickness (ILM to RPE) was significantly lower in affected vs. unaffected eyes for all ETDRS subfields (p<0.0001). Comparing only stage 1 affected eyes to unaffected eyes, outer retinal thickness in stage 1 eyes were significantly lower than unaffected eyes in all ETDRS subfields (p<0.01) except the foveal subfield, with the highest discrimination observed for the inner temporal subfield (AUC=0.96). Mean signal intensities in the outer retina, but not in the inner retina, were significantly lower in stage 1 eyes compared with unaffected eyes in all inner ETDRS subfields, but not in the foveal or outer subfields. Stages 2-4 had more significant changes compared to unaffected eyes.
Quantitative analysis of OCT scans revealed significant differences in retinal thickness and signal intensities between unaffected and affected eyes, even for those in the lowest severity category, suggesting its potential utility in HCQ toxicity screening in pre-symptomatic patients.
This is a 2020 ARVO Annual Meeting abstract.
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