ASSESSING THE MICROSTRUCTURES OF THE HUMAN CORNEA USING GABOR-DOMAIN OPTICAL COHERENCE MICROSCOPY WITH LARGE FIELD OF VIEW AND HIGH RESOLUTION

Abstract

 

Purpose

 

We propose here to investigate human corneal microstructures using a large field of view and high volumetric-resolution imaging modality, Gabor-Domain Optical Coherence Microscopy (GD-OCM), in order to provide insights into corneal layer functionality and disease mechanisms.

 

Methods

 

We first developed a bioreactor to control the anatomy of human excised corneas. A syringe was used to fill the anterior chamber with a balanced salt solution, thus creating aqueous humor like pressure. The microanatomy of these corneas was then imaged using GD-OCM that combines the high sectioning capability of optical coherence tomography (OCT) with the high lateral resolution of confocal microscopy. The system achieved high-contrast imaging with a field of view of 1 x 1 mm² and volumetric cellular resolution of 2 μm across a thickness of up to 2 mm in tissue. The system fitted on a movable cart and the handheld scanning probe was attached to an articulated arm that may be adjusted to image different locations of the cornea. For real time visualization, we implemented a parallelized Multi-Graphic Processing Units (GPU) architecture to speed up the processing of data. The overall time to 3D visualization, including acquisition that is 1.5 minutes, processing and rendering of a 1000 × 1000 × 400 voxels, was less than 2 minutes compared to 2 hours on a conventional CPU. In this investigation, we focused on imaging the microanatomy of the corneal stroma keratocytes as well as corneal endothelial cells.

 

Results

 

The imaging system produced 3D high resolution of the cornea over a 1 x 1 mm² field of view as shown in Figure 1. Results showed high contrast images of stroma keratocytes and the distribution of endothelial cells comparable to standard in vivo confocal microscopy.

 

Conclusions

 

We demonstrate, with a new imaging modality, imaging key features of the corneal layers, such as stroma, the Descemet’s membrane, and endothelial cells across a large field of view that itself enables accurate counting of the number of cells. Future work will include correlating the morphology of the cells to their functionality. This research is on the path to provide insights into the mechanism of corneal disease and particularly endothelial cells dysfunction.  

 

Image of corneal microstructures