Abstract
Purpose :
To develop ultra-high speed OCT technology for non-contact, volumetric, cellular resolution imaging of the rodent and human cornea.
Methods :
A line-scan, spectral domain OCT system that utilizes a Powell lens was designed for corneal imaging (PL-LS-SD-OCT). The system is based on a free-space Michaelson interferometer, powered by a supercontinuum laser with a filtered spectral range of 640 nm – 850 nm. A Powell lens with was used to generate a top-hat intensity line profile. The system offers almost isotropic resolution of ~2.2×2.2×1.8 μm (x × y × z) in free space, ~87 dB maximum sensitivity with a ~2 dB sensitivity fluctuation along the line direction measured for image acquisition rate of 2000 fps and 2.5 mW incident power. The new PL-LS-SD-OCT system was tested by imaging rodent cornea (mice and rats). Next, the system will be used for in-vivo imaging of the human cornea.
Results :
Figure A shows a XZ plane cross-sectional image of a rat cornea. All 5 major corneal layers are resolved. EPI: epithelium, STR: stroma, DM: Descemet’s membrane, END: endothelium, red arrow: Bowman’s membrane. Figures B shows an enface image of the corneal stroma where keratocytes (yellow arrows) and thin stromal nerves (red arrows) are resolved. Figure C shows an image of the cellular structure of the endothelium layer. Dark spots inside the cells (green arrows) correspond to reflections from cellular nuclei.
Conclusions :
The novel PL-LS-SD-OCT system combines micrometer scale resolution and ultrahigh image acquisition rate required for in-vivo cellular resolution imaging of the animal and human cornea.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.