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Benjamin Reiss, Lindsay Smithen, Sam Mansour, Rishi Singhal, Tony Chen, Aisha Mumtaz; A Novel Method for Ellipsoid Layer Analysis with Hydroxychloroquine Use. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):255.
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© ARVO (1962-2015); The Authors (2016-present)
To develop a novel method for analyzing the Ellipsoid Zone (EZ) on Optical Coherence Tomography (OCT) for earlier detection of hydroxychloroquine toxicity to the retina.
All patients screened for hydroxychloroquine toxicity at the George Washington University Department of Ophthalmology from January 1, 2012 to November 1, 2014 were identified. Inclusion criteria consisted of having a dilated fundus exam and at least one High Definition Spectralis OCT (HD-OCT, Heidelberg Engineering, Heidelberg, Germany). Exclusion criteria consisted of the presence of any plaquenil unrelated maculopathy or glaucoma. The EZ intensity was analyzed using the National Institutes of Health's Medical Imaging, Processing, Analysis, and Visualization (MIPAV) software. Five volumes of Interest (VOIs) were drawn over the EZ of both eyes 500 microns superior, inferior, nasal, and temporal to the fovea as well as directly subfoveal (Figure 1). Average voxel intensity was recorded. To account for variability in signal quality and intensity from scan to scan, additional VOIs were drawn on the RPE directly beneath each EZ VOI to serve as an internal control for each scan; the ratio of each respective Ellipsoid VOI to RPE VOI was used for calculations.
One hundred ninety-three patients were included in the study. One hundred seventy-three were female, and 20 were male. Average age and duration of hydroxychloroquine use was 61.8 years and 4.6 years, respectively. No patients developed clinical signs of toxicity from routine screening. EZ intensity was plotted for completed years of use as shown in Figure 2. EZ intensity for patients with more than ten years of hydroxychloroquine only decreased by 0.74% compared to those with less than 10 years of use (result not significant).
Routine use of hydroxychloroquine does not cause a detectable change in the ellipsoid zone, signifying no subtle damage to photoreceptors.
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