Portable in vivo confocal ophthalmoscope for non-contact imaging of the cornea and anterior segment of the eye

We present a novel portable in vivo confocal ophthalmoscope (PICO) designed to enable non-contact imaging of the cornea and anterior segment of the eye. PICO uses a broadband light source and diffraction gratings to acquire two-dimensional confocal images without any beam scanning mechanisms. A dry objective lens with a long working distance was used to image the external eye without making physical contact with the cornea or ocular surface. Lateral resolution of 2.2-2.7 µm and axial resolution of 8.1 µm were achieved with PICO when imaging ex vivo animal corneas, and provided reliable signal levels when images were acquired at high speeds of 100-135 frames/sec. The resulting images enable clear visualization of characteristic cellular morphological details of the cornea, including epithelial cells, corneal nerve fibers, stromal keratocytes, and endothelial cells. These preliminary results from high-speed PICO imaging of animal corneas merit further evaluation of the prototype device for in vivo human corneal imaging.