INVESTIGATING MICROSTRUCTURES OF HUMAN CORNEAL ENDOTHELIAL CELL MICROENVIRONMENT USING HIGH RESOLUTION IMAGING GABOR-DOMAIN OPTICAL COHERENCE MICROSCOPY

Abstract

 

Purpose

 

We propose here to use a high volumetric resolution imaging modality, Gabor-Domain Optical Coherence Microscopy (GD-OCM), to observe corneal endothelial cells and corneal microstructures in order to better understand corneal layers functionality

 

Methods

 

GD-OCM combines high sectioning capability of optical coherence tomography (OCT) and high lateral resolution of confocal microscopy to achieve high-contrast imaging with volumetric cellular resolution of 2 μm across a thickness of up to 2 mm in tissue. The current GD-OCM system fits on a movable cart. The handheld scanning probe is attached to an articulated arm that can be easily adjusted. The light source is a superluminescent diode laser centered at 840 nm with 100 nm FWHM (BroadLighter D-840-HP-I, Superlum®, Ireland). The microscope objective probe incorporates a liquid lens, which allows dynamic-focusing in order to image different depths of the sample. A custom dispersion compensator and a custom spectrometer with a high-speed CMOS line camera (spl4096-70km, Basler Inc.) are used to acquire the spectral information. We recently implemented and will also present a parallelized Multi-Graphic Processing Units (GPU) architecture of the system to allow real-time visualization of the sample. The overall time to 3D visualization, including acquisition, processing and rendering of a 1000 × 1000 × 400 voxels, is less than 2 minutes compared to 5 hours on a conventional CPU. The lateral resolution of 2 µm (significantly far from conventional OCT) coupled to the high axial resolution of 2µm allowed analyzing the en face and cross sectional imaging of corneal layers. This imaging modality, with 1 x 1 mm2 field of view and 1 mm imaging depth in corneal tissue, was devoted to investigate the microenvironment of excised human corneas

 

Results

 

The imaging system revealed high contrast images of stroma fibers and the distribution of endothelial cell nuclei. Cross-section x-z images also allow the visualization of stroma keratocytes

 

Conclusions

 

This new imaging modality revealed key features of the corneal layers. Future work will consist of studying these features in order to correlate their morphology to their functionality. This work will provide insights into the mechanism of corneal diseases and particularly endothelial cells dysfunction

 

 

Keywords: 481 cornea: endothelium • 552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • 494 degenerations/dystrophies