Thin Outer Nuclear Layer and Retinal Volume Measurements with Automated Segmentation on Optical Coherence Tomography Supports Hydroxychloroquine Toxicity

摘要

Purpose : Hydroxycloroquine (HCQ) is a frequently used medication to treat conditions including rheumatoid arthritis, lupus, and inflammatory joint disease. HCQ toxicity is rare but devastating due to retinal atrophy. Screening guidelines for HCQ toxicity identify optical coherence tomography (OCT) as an important tool with atrophic changes present in the parafoveal macula in confirmed cases. We hypothesize patients with HCQ toxcicity will show low retinal volumes (RV) and thickness measurements of the outer nuclear layer (ONL) on automated segmentation OCT as compared to healthy controls. Methods : We performed a retrospective chart review of patients evaluated at Carle Foundation Hospital with OCT from 2011-2015 (Spectralis HRA+OCT, Heidelberg Engineering, Germany). Subjects had a confirmed diagnosis of HCQ toxicity made by a retina specialist. The mean age of affected subjects was 68 and the control group was 65. Diagnosis was based on clinical exams and ancillary testing (including automated visual field tests, fundus autofluorescence, and OCT). OCT was used for further analysis by dividing the retina into foveal, parafoveal, and perifoveal zones with an EDTRS overlay grid and measurements of retinal thickness and volumes were recorded from each region (Figure 1a). The segmentation function in Heidelberg Eye Explorer (1.9.10.0) automatically isolated the ONL (Figure 1b). Cases with image quality less then 20 were excluded. Age-matched controls were used for comparison. The two groups were compared using a two-sample T-Test. Carle Foundation Hospital Institutional Review Board approved the study. Results : Thirteen eyes from 7 subjects had confirmed HCQ retinopathy. Fourteen eyes from 14 subjects with normal retinas served as controls. Statistical significance between the two groups was observed in all regions for thickness and volume measurements, with 95% confidence interval (Table 1). Conclusions : This study confirms our hypothesis that the ONL is thinner in patients with HCQ toxicity. ONL thickness and overall RV serve as a significant comparison tool for patients with HCQ toxicity as compared to healthy controls. These traits may be a valuable marker for identifying patients with toxicity. Further investigation is needed to explore whether a threshold thickness using automatic segmentation could serve as a screening tool for HCQ retinopathy.This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.??View OriginalDownload Slide.