Ultrahigh-resolution imaging of human donor cornea using full-field optical coherence tomography

Abstract

A feasibility study of ultrahigh-resolution full-field optical coherence tomography (FF-OCT) for a subcellular-level imaging of human donor corneas is presented. The FF-OCT system employed in this experiment is based on a white light interference microscope, where the sample is illuminated by a thermal light source and a horizontal cross-sectional (en face) image is detected using a charge coupled device (CCD) camera. A conventional four-frame phase-shift detection technique is employed to extract the interferometric image from the CCD output. A 95-nm-broadband full-field illumination yields an axial resolution of 2.0 microm, and the system covers an area of 850 microm x 850 microm with a transverse resolution of 2.4 microm using a 0.3-NA microscope objective and a CCD camera with 512 x 512 pixels. Starting a measurement from the epithelial to the endothelial side, a series of en face images was obtained. From detected en face images, the epithelial cells, Bowman's layer, stromal keratocyte, nerve fiber, Descemet's membrane, and endothelial cell were clearly observed. Keratocyte cytoplasm, its nuclei, and its processes were also separately detected. Two-dimensional interconnectivity of the keratocytes is visualized, and the keratocytes existing between collagen lamellaes are separately extracted by exploiting a high axial resolution ability of FF-OCT.

Appearance of the Retina With Full-Field Optical Coherence Tomography

“…It has been used for imaging of the retina, 4 cornea, [5][6][7] corneal limbus, 8 and other ophthalmic tissues, along with other biological tissues such as brain, 9 breast, 10,11 and gastrointestinal tissues. 12 The lack of the need for fixation and contrast agents in FFOCT is an advantage, particularly in longitudinal studies where a single retinal explant, for example, is to be imaged at multiple timepoints.…”

Evaluation of ablation differences in air and water for hard tissues using full-field optical coherence microscopy

“…resolution during the depth scanning, and the range of the imaging depth is only determined by the mechanical scanner and working distance of the objective. The OCM is commonly applied to the examination of ocular tissues [20], cells [21], and semiconductors [22]. However, the applications of full-field OCM for the characterization of laserinduced craters in hard tissue have not yet been reported.…”

Assessment of Sentinel Node Biopsies With Full-Field Optical Coherence Tomography

“…As compared to confocal systems, FFOCT further holds the advantage not to require lasers or fast scanning elements; the technique can be integrated in a simple setup. The FFOCT has already been evaluated in the pathology laboratory in various preclinical studies on human skin, 24,25 pulmonary, 26 urologic, 27 and gastrointestinal tissue, 28 retina and cornea, 29,30 and brain. 31 Recently, a preclinical study was performed on breast tissue samples 32 and achieved sensitivity of 92% and specificity of 77%.…”