Biomechanical Impact of Localized Corneal Cross-Linking Beyond the Irradiated Treatment Area

Abstract

Purpose:

To investigate the stiffening effect of localized corneal crosslinking (L-CXL) within and beyond the irradiated region in three dimensions.

Methods:

Ten porcine eyes were debrided of epithelium and incrementally soaked with 0.1% riboflavin solution. Using a customized, sharp-edged mask, half of the cornea was blocked while the other half was exposed to blue light (447 nm). The three-dimensional biomechanical properties of each cornea were then measured via Brillouin microscopy. An imaging system was used to quantify the optimal transition zone between crosslinked and non-crosslinked sections of the cornea when considering light propagation and scattering.

Results:

A broad transition zone of 610 μm in width was observed between the fully crosslinked and non-crosslinked sections, indicating the stiffening response extended beyond the irradiated region. Light propagation and the scattering induced by the riboflavin-soaked cornea accounted for a maximum of 25 and 159 + 3.2. μm respectively.

Conclusions:

The stiffening effect of localized CXL extends beyond that of the irradiated area. When considering localized CXL protocols clinically, it will be important to account for increased stiffening in surrounding regions.