Thermal Damage Distribution in Human Cornea Following Thermal Keratoplasty: An FTIR Study

Hyperopia (farsightedness) and presbyopia are two common eye diseases, especially seen in the elderly. In both cases, eyes lose the ability to focus on nearby objects due to change in the cornea shape or stiffening of the lens. In recent years, thermal treatment of cornea in the form of Conductive Keratoplasty (CK) procedures has been successfully utilized to reshape the cornea. In the CK treatment, a thin radiofrequency (RF) probe is inserted into the cornea and heat is delivered into the stroma [1]. The heat treatment causes collagen denaturation and mechanical shrinkage of the collagen fibers. In the CK treated region, the collagen fibers are aligned in a circular fashion. Therefore, the shrinkage of these fibers steepens the curvature of the cornea. The amount of heat delivered to the stroma during CK treatment can be controlled either by changing the applied RF power or the heating time. In this study, we utilized Fourier Transform Infrared Spectroscopy (FTIR) to map the thermal damage distribution in the human cornea tissue following simulated CK treatment.