Abstract
Purpose :
Recently, full-field OCT (FFOCT) demonstrated en face cell-resolution images of the in vivo cornea, captured in contactless way with large field-of-view (1.3 mm2), beneficial comparing to the state of the art confocal microscopy. Obtaining those high-signal FFOCT images required averaging of 20 single images, priorly aligned with a lateral registration algorithm. In this work we demonstrate an improved FFOCT instrument, capable of capturing high-signal images in a single shot. This improvement eliminates the need for image registration and averaging, opening a possibility for real-time corneal viewing. We show that images could be captured not only from the central corneal region, but also from the peripheral cornea, conjunctiva and limbus, revealing the palisades of Vogt and vessel blood flow.
Methods :
Images of the anterior eye were obtained from three healthy subjects using a combined FFOCT-OCT instrument. OCT provided the axial position of the eye, which was used to correct in real-time the focus of the FFOCT reference arm, increasing the signal level in FFOCT images. Acquisition speed of 275 images per second was sufficient to freeze the movements of the eye and visualize the propagation of blood in the limbal and conjunctival vessels.
Results :
High-signal non-averaged FFOCT images revealed structures in central and peripheral cornea, including tear-film, superficial epithelial cells with nuclei, sub-basal nerve plexus (SNP), stromal keratocytes and nerves, endothelium. In the limbus the ridge-shaped palisades of Vogt with diameter around 30 µm and blood vessels were visible. Moreover, it was possible to view the propagation of blood cells inside the vessels and measure flow of 0.3 millimiters/second, in agreement with the literature.
Conclusions :
Full-field OCT can capture high-signal images from central and peripheral cornea, conjunctiva and limbus, with revealed palisades of Vogt and blood vessels. Propagation of blood flow can be viewed and quantified. High-signal images are captured in a single shot, opening the possibility for real-time viewing. These points, together with the contactless operation, cell-resolution and millimiter-size field of view, make FFOCT a promising candidate for becoming a useful clinical tool in the future.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.