Influence of temperature and time on thermally induced forces in corneal collagen and the effect on laser thermokeratoplasty

Abstract

The course of the contractive forces during and after heating is a complicated function of the spatial time/temperature profile. Laser thermokeratoplasty lesions produced with 2 irradiation times showed different stages of denaturation and induced refractive change.

A boundary element model of the human eye undergoing laser thermokeratoplasty

“…In the continuous wave laser treatment, the spatial temperature profiles in Figure 8 agree qualitatively with the numerical results demonstrated in [9] and [10]. It should be noted that the intracorneal focusing of the laser modeled by Brinkmann and co-workers [9], [10] is a better model compared to the present one where the laser is assumed to be focused only on the corneal surface.…”

“…It should be noted that the intracorneal focusing of the laser modeled by Brinkmann and co-workers [9], [10] is a better model compared to the present one where the laser is assumed to be focused only on the corneal surface. This aspect may be considered in future investigations to further improve the complete eye model presented in this study.…”

“…This model was subsequently used by Brinkmann and co-workers to investigate the thermal responses of the human cornea during L-TKP under various conditions [7], [8], [9], [10]. In [11] and [12], the cornea was modeled as a rectangular strip of finite thickness.…”

Identification of a suitable sterilisation method for collagen derived from a marine Demosponge

“…Although the denaturation process of collagen is complex and not fully understood, its analysis requires an understanding of collagen on a molecular level (Brinkmann et al, 2000). The triple helical structure of collagen is based on non-covalent interactions between vicinal polypeptide chains and arises from the abundance of the amino acids glycine, proline and hydroxyproline (Wiegand et al, 2009).…”

“…It's likely that hydrogen bonds connecting the three chains of the triple helix, cross-links interconnecting collagen molecules and peptide bonds forming the α-helices all play important roles in the denaturation of collagen (Brinkmann et al, 2000). Thermal denaturation is considered to be a relevant indication of collagen's potential future use as, or as part of, a biomaterial due to the decreased in vivo stability of partially denatured collagen (Yunoki, Suzuki, and Takai, 2003).…”