Abstract
Purpose :
To develop a second-generation Powell lens-based, line-scan SD-OCT system (PL-LS-SD-OCT) with improved sensitivity and depth-of-focus (DOF) for non-contact, volumetric, cellular resolution imaging of the rodent and human cornea.
Methods :
An existing PL-LS-SD-OCT system was re-designed to expand the DOF and improve the system’s sensitivity. These aims were achieved by replacing some of the optical components, the light source, as well as the CMOS area camera. The novel design of the system offers almost isotropic resolution of ~2.3×2.3×1.8 μm (x × y × z) in free space, corresponding to ~1.3 μm axial resolution in biological tissue assuming average refractive index of 1.38. The new design resulted in 2× improvement in the DOF, 2× improvement in the lateral FOV and > 3 dB improvement in the system’s sensitivity (>90 dB maximum sensitivity measured for image acquisition rate of 2,000 fps and 2.5 mW power incident on the imaged object). The new PL-LS-SD-OCT system was tested by imaging cucumber and rat cornea. Next, the system will be used for in-vivo imaging of the human cornea.
Results :
Figure A shows a photograph a cucumber slice with region of interest (ROI) marked with the red square. Figure B is a magnified view of the ROI showing a seed (black arrow). Figure C is an OCT enface image showing the cellular structure of the tissue surrounding the cucumber seed. A photograph of imaging the rat cornea is shown in Fig. D. Figure E shows an OCT image of the cellular structure of the corneal endothelium. Dark spots inside the cells (red arrows) correspond to reflections from cellular nuclei.
Conclusions :
The improved design of the PL-LS-SD-OCT system resulted in 2× expansion of the DOF and > 3dB improvement of the system’s sensitivity. Images acquired with the system show the cellular structure of plan tissue and the rat cornea.
This abstract was presented at the 2023 ARVO Imaging in the Eye Conference, held in New Orleans, LA, April 21-22, 2023.