Terahertz Scanning for Evaluation of Corneal and Scleral Hydration

The aim of the investigation was to study the prospects of using continuous THz scanning of the cornea and the sclera to determine water concentration in these tissues and on the basis of the obtained data to develop the experimental installation for monitoring corneal and scleral hydration degree.

Materials and Methods. To evaluate corneal and scleral transmittance and reflectance spectra in the THz range, the developed experimental installations were used to study 3 rabbit corneas and 3 scleras, 2 whole rabbit eyes, and 3 human scleras. Besides, two rabbit eyes were studied in vivo prior to keratorefractive surgery as well as 10 and 21 days following the surgery (LASIK).

Results. There have been created novel experimental installations enabling in vitro evaluation of frequency dependence of corneal and scleral transmittance coefficients and reflectance coefficients on water percentage in the THz range. Decrease in corneal water content by 1% was found to lead to reliably established decrease in the reflected signal by 13%. The reflectance spectrum of the whole rabbit eye was measured in the range of 0.13–0.32 THz. The study revealed the differences between the indices of rabbit cornea and sclera, as well as rabbit and human sclera.

There was developed a laboratory model of the installation for in vivo evaluation of corneal and scleral hydration using THz radiation.

Conclusion. The preliminary findings show that the proposed technique based on the use of continuous THz radiation can be employed to create a device for noninvasive control of corneal and scleral hydration.

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Iomdina E.N., Seliverstov S.V., Sianosyan A.A., Teplyakova K.O., Rusova A.A., Goltsman G.N. Terahertz Scanning for Evaluation of Corneal and Scleral Hydration. Sovremennye tehnologii v medicine 2018; 10(4): 143, https://doi.org/10.17691/stm2018.10.4.17