Eye injury is a significant clinical problem and leading cause of severe visual impairments. It is estimated that about 55 million eye injuries occur annually worldwide, and incidence of eye trauma in the United States is estimated to be over 2 million. Cornea is outermost part of the eye, and thus most likely to sustain a damage. It is a highly specialized tissue dedicated to refract light onto the retina, and thus maintaining its transparency is a paramount. Corneal wound healing is a complex process driven by cytokine and growth factor signaling, and includes cell apoptosis, proliferation, differentiation as well as remodeling of the extracellular matrix. In the initial phase, damage to the epithelium triggers release of cytokines including interleukin-1, which initiates apoptosis of the keratocytes located directly beneath the wound. The apoptosis results in the release of the intracellular content into the surrounding areas. This event attracts potentially excessive amount of inflammatory cells, which could further damage the tissue. Any disruption of the healing process can affect the structural integrity of the extracellular matrix resulting in scarring, corneal haze, and in extreme cases blindness.
We hypothesize that treating injured eyes with a femtosecond laser can modulate inflammatory cytokines and growth factors, leading to an enhanced healing while minimizing scarring and corneal haze. The femtosecond laser, when restricted to regimes below optical breakdown, imparts low-density-plasma into the target tissue, which ionizes and dissociates interstitial water, thus producing reactive oxygen species (ROS). These short-lived ROS photo-oxidize target cytokines, which reduces their binding affinity. Tailoring of the process could manage the post-injury inflammation to accelerate healing while minimizing or eliminating adverse effects of trauma.
