The EXPLORE Study - The Use of Binocular OCT Imaging for the Assessment of Ocular Disease

Optical coherence tomography (OCT) is an imaging modality, first described in 1991, that provides cross-sectional images of the eye in a non-invasive manner. OCT is analogous to ultrasonography but measures the "echoes" of light waves rather than sound and, as a result, generates extremely high-resolution images (\~5 μm axial resolution). Although OCT has already proven revolutionary in ophthalmology, current OCT systems are large, expensive, and require skilled personnel for image acquisition and interpretation. Furthermore, current OCT systems are limited to examination of specific regions of single eyes - for example, separate devices are typically required for anterior segment (e.g., cornea) versus posterior segment (e.g., retina) imaging. A new form of OCT imaging has recently been developed - so-called "binocular" optical coherence tomography (OCT) (Envision Diagnostics, Inc., California).1,2 Binocular OCT addresses many of the short-comings of conventional OCT devices. Binocular OCT extends the application of OCT devices beyond that of simple, cross- sectional imaging to a diverse array of diagnostic tests. The binocular design also removes the need for additional personnel to perform testing (i.e., the device can be self-operated in an automated manner), and allows for novel testing to be performed that is not possible with monocular imaging. In particular, binocular OCT devices have the potential to perform automated, quantitative pupillary measurements - an entirely novel application for this imaging modality, plus also adds a number of unique capabilities. In particular, binocular OCT removes the need for additional personnel to acquire the images by enabling patients to align the optical axes of the instrument with the optical axes of their own eyes. The system also employs recently developed "swept-source" lasers as its light source, allowing it to see deeper into the eye than conventional OCT systems. Finally, binocular OCT systems allow image capture