Real-time non-contact cellular imaging and angiography of human cornea and limbus with common-path full-field/SD OCT

In today's clinics, a cell-resolution view of the cornea can be achieved only with a confocal microscope (IVCM) in contact with the eye. Here, we present a common-path full-field/spectral-domain OCT microscope (FF/SD OCT), which enables cell-detail imaging of the entire ocular surface in humans (central and peripheral cornea, limbus, sclera, tear film) without contact and in real-time. Real-time performance is achieved through rapid axial eye tracking and simultaneous defocusing correction. Images contain cells and nerves, which can be quantified over a millimetric field-of-view, beyond the capability of IVCM and conventional OCT. In the limbus, palisades of Vogt, vessels, and blood flow can be resolved with high contrast without contrast agent injection. The fast imaging speed of 275 frames/s (0.6 billion pixels/s) allows direct monitoring of blood flow dynamics, enabling creation of high-resolution velocity maps. Tear flow velocity and evaporation time can be measured without fluorescein administration. Currently a cell-resolution map of the human cornea can only be obtained in the clinic with a confocal microscope in contact with the eye. Here the authors develop a full-field/spectral-domain OCT microscope (FF/SD OCT) to enable cell-level detail of the entire ocular surface, as well as blood flow and tear dynamics.