En Face Optical Coherence Tomography Imaging of the Photoreceptor Layers in Hydroxychloroquine Retinopathy

Abstract

To investigate the application of en face optical coherence tomography (OCT) imaging in eyes with hydroxychloroquine (HCQ) retinopathy. Retrospective case series. Setting: Institutional. Sixty-two eyes of 31 Asian patients with HCQ retinopathy. Macular volume scanning using swept-source OCT was performed in 6× 6-mm and 9× 9-mm areas centered on the fovea. Segmentation of the photoreceptor layers was automatically performed between the inner border of the ellipsoid zone and that of the retinal pigment epithelium-Bruch membrane complex to obtain en face OCT images. Findings from the en face images were qualitatively and quantitatively evaluated; they were analyzed and correlated with the fundus autofluorescence and visual field findings. En face OCT findings. All eyes with HCQ retinopathy had a beaten-bronze appearance in the areas with photoreceptor defects, whereas those with intact photoreceptors had areas with smooth surfaces, which were occasionally demarcated by hyporeflective margins, on the en face OCT images. The presence and extent of the retinopathy could be quickly determined using the images. They also provided quantitative information on the progression based on the areas of intact photoreceptors compared over several visits. Furthermore, the area of central intact photoreceptors significantly correlated with the mean deviation, pattern standard deviation, and visual field index of 30-2 visual field examinations (all P < .001). En face OCT may be useful for visualizing the presence and extent of HCQ retinopathy and its progression. The area of central intact photoreceptors measured on en face OCT images showed a significant association with functional visual field defects. This imaging may be a helpful adjunct for screening and follow-up examinations of HCQ retinopathy.