Automated Segmentation Measurements of the Outer Nuclear Layer in Determining Cases of Hydroxychloroquine Toxicity: A Retrospective Study

Purpose: The purpose of this article is to investigate automated segmentation measurements of the outer nuclear layer to differentiate patients with hydroxychloroquine toxicity from healthy individuals. Methods: A 5-year retrospective, case-controlled, interventional study of hydroxychloroquine toxicity patients was conducted. Measurements of the outer nuclear layer were obtained with use of commercially available segmentation software and compared with controls. Results: Seven participants (13 eyes) with toxicity and 16 controls (16 eyes) were included. The data comparing the parafoveal, perifoveal, foveal, and overall regions were significant both in thickness ( P < .0001, P < .0001, P = .0029, and P < .0001, respectively) and volume ( P < .0001, P < .0001, P < .0001, and P < .0001, respectively). The CI indicates there is 95% confidence that toxicity patients have between 147 μm and 201 μm less thickness (average 174 μm) and between 0.39 mm3 and 0.55 mm3 less volume (average 0.47 mm3). Conclusions: The automated segmentation function can correctly differentiate thinner outer nuclear layer measurements in patients with toxicity. This study is the first to establish the ranges of thickness and volume of the outer nuclear layer with commercially available segmentation. These results provide the first step in determining whether automated segmentation measurements of the outer nuclear layer can be used as an objective screening tool for hydroxychloroquine toxicity.