To test the feasibility of measuring the entire thickness profiles of the epithelium and contact lens (CL) in vivo, using high-speed and high-resolution spectral-domain optical coherence tomography (SD-OCT).
A custom-built, long scan depth SD-OCT was developed based on a complementary metal oxide semiconductor (CMOS) camera, and the axial resolution was approximately 5.1 μm in tissue. Five eyes of five subjects were imaged twice across the horizontal meridian before and while wearing one CL. Semiautomatic measurement was done to yield the entire thickness profiles of the epithelium, total cornea, and CL after correcting for optical distortion.
The full width and depth of the epithelium, ocular surface, and CL were clearly visualized. The epithelial thickness at the center was 51.9±3.5 μm; it remained at this thickness across the central 7 mm diameter and then increased at both temporal and nasal peripheries. The CL profile showed the thinnest point at the center with thickness of 100.3±4.9 μm. The thickness increased toward the midperiphery and then decreased at the edge.
This pilot study demonstrated the feasibility of using high-speed CMOS-based OCT to evaluate the entire thickness profiles of the epithelium and CL in vivo. Further development will be needed to extend the scanning from 2D to 3D with a robust automatic image processing ability.