The Application of Terahertz Technology in Corneas and Corneal Diseases: A Systematic Review

Terahertz (THz) waves reside in the electromagnetic spectrum between the microwave and infrared bands. In recent decades, THz technology has demonstrated its potential for biomedical applications. With the highly unique characteristics of THz waves, such as the high sensitivity to water and optimal spatial resolution coupled with the characteristics of the human cornea, such as its high water content, THz technology has been explored as a potential modality to assess corneas and corneal diseases. This systematic review provides an overview of the characteristics of THz waves, the safety profile of THz technology in the field of ophthalmology, and its clinical applications, including the objective evaluation of the corneal hydration, tear film, dry eye disease, corneal endothelium, corneal elasticity, and scarring. The paper also presents our viewpoint on the present challenges and future directions of THz technology prior to its broader integration into clinical practice.