Experimental investigation of the safety of terahertz radiation in corneal hydration assessment

Abstract

To assess the safety of pulsed THz radiation with various parameters (time, power, and frequency) for the cornea in a rabbit model. The sample for the current study consisted of 18 Chinchilla rabbits (18 eyes). Corneal imaging and epithelial cell density before and after the exposure were evaluated using confocal laser scanning microscopy (CLSM). The histological study for objective assessment of the cornea state (day 1 and day 14) was performed after experiment termination. Single and multiple exposures of laser radiation at a frequency below 0.1 THz and power density below 30 nW/cm2 do not cause visible structural changes in any layers of the rabbit cornea. The results obtained in the long-term period showed insignificant reversible morphological changes only within the epithelium. The described parameters of terahertz and subterahertz radiation can be considered safe for assessing changes in corneal epithelium hydration level using non-invasive methods based on THz reflectometry.