3D cellular imaging of the cornea with Gabor-domain optical coherence microscopy

A Gabor-domain optical coherence microscope (GDOCM) with 2-micrometer invariant lateral and axial resolutions and a working distance of 15 mm was developed for 3D imaging of corneal tissue over a 1 mm2 field of view. The increased working distance over the previous in-contact implementation enables imaging of corneal tissue inside the viewing chamber in which corneas are stored after recovery from donors. The GDOCM system was used to image excised human corneas. 3D images of the cornea were acquired by imaging through the PMMA viewing chamber. The images achieved cellular resolution in the volume being imaged. Due to the curvature of the cornea, the endothelium, a single layer of cells lining the posterior surface of the cornea, cannot be viewed in a single en face image. A flattening algorithm was implemented to obtain an en face view of the endothelium. The GDOCM images were compared with those acquired with a specular microscope commonly used in eye banks for endothelial evaluation, and the endothelial cell density was assessed for both sets of images. A key advantage of GDOCM is the capability to image the entire thickness of the cornea in 3D with cellular resolution over a large field of view.