En-face imaging as a method for monitoring changes in the inner segment (IS)/outer segment (OS) band in retinitis pigmentosa

摘要

Purpose : To compare en-face imaging of the area of the intact IS/OS band (aka EZ band) derived from wide-field swept-source optical coherence tomography (ssOCT) volume scans to current measurements of IS/OS band width on OCT averaged B-scans, and measurements of the borders of rings/arcs seen on short-wavelength fundus autofluorescent (SW-FAF) images in patients with retinitis pigmentosa (RP). Methods : Wide-field, ssOCT cube scans (9 x12 mm, 256 B-scans, 512 A-scans, DRI-OCT, Topcon, Inc) were obtained from 7 eyes of 6 patients with RP (autosomal recessive: 2, autosomal dominant: 2, Usher syndrome type II: 2) aged 19 to 60 years with BCVAs ranging from 20/20 to 20/25. OCT macular volume and averaged B-scans, and SW-FAF images, were also obtained using Spectralis HRA+OCT (Heidelberg Eng). Following manual correction of the automated Topcon segmentation of the IS/OS band and OS/retinal pigment epithelium (OS/RPE) layers, the average reflective intensity of en-face slabs of varying thickness were generated with these borders as references using special purpose software (ATL 3D-Suite).[1,2] For each eye, the lateral extent of the intact IS/OS area was compared to the width of the band measured on OCT B-scans and to the borders of the hyperFAF ring/arc on the SW-FAF image following registration of the images. Results : For the en-face images (Fig. 1B), slabs (Fig. 1A), with the IS/OS band as reference, optimized visualization of the boundary of the intact IS/OS area for 6 eyes (Fig. 1B); for one eye, the reference was the OS/RPE. For all 7 eyes, there was good agreement between the lateral extent of the IS/OS area and width of the band measured on the averaged B-scans (Fig.1B, C, solid vertical lines), as well as with the locations of the terminations of the band on individual ssOCT B-scans. In addition, all 7 eyes had a ring/arc of hyperFAF (Fig. 1D). The inner border of the hyperFAF area (Fig. 1D) corresponded to the en-face boundary of the IS/OS area (Fig. 1B). Conclusions : En-face imaging has potential clinical value for visualizing and tracking changes in the integrity of the IS/OS band in patients with RP. 1. Fortune et al. IOVS 2014; 2. Hood, Fortune et al. IOVS 2015. This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016. ??View OriginalDownload Slide.