Corneal Hydration Sensing with Thz Illumination

UCLA researchers in the Department of Bioengineering have created a novel imaging system that measures corneal hydration levels by utilizing terahertz (THz) frequency (100 GHz - 1 THz) sources and detectors.

Proper corneal hydration levels are critical to maintaining optical vision. Currently, corneal hydration is measured using ultrasound optical pachymetry, which involves measuring the central corneal thickness and extrapolating the average water content from these measurements. However, mapping from thickness to hydration is very inaccurate and is limited by inherent constraints. Another method uses confocal Raman spectroscopy to remotely measure corneal hydration. However, the excitation illumination influence necessary to achieve accurate measurements exceeds the ANSI regulations for use in humans by orders of magnitude.

Researchers at UCLA have developed an imaging system to detect corneal hydration levels by illuminating the cornea with low power, low energy, THz frequency light and measuring the magnitude of the reflected THz signal. The system is capable of resolving 0.18% changes in the water concentration of the cornea in vivo and results suggest a ~3x increase in dynamic range over ultrasound based pachymetry.

DEVELOPMENT-TO-DATE: Researchers have created a working prototype and have successfully completed a preliminary in-vivo animal trials.