Abstract
Purpose: :
To evaluate the feasibility of crosslinking clear collagen gel (PriagelTM, PriaVision Inc, Menlo Park, CA) into an adherent and resilient anterior stromal substitute for corneal reconstruction after lamellar graft dissection.
Methods: :
Six porcine enucleated eyes were partially trephinated using an 8.5 mm Barron-Hessburg trephine followed by a deep lamellar dissection. The lamellar bed was filled with the human recombinant Type 1 collagen gel mixed with a customized crosslinking agent (PriagelTM) and then irradiated with 375 nm.UVA light at 3 mW/cm2 for 30 seconds. High resolution OCT (Visante, Carl Zeiss, Jena, Germany) was used to measure central corneal thickness (CCT) before and after corneal trephination. The OCT flap tool was used to measure the thickness of the corneal augmentation layer centrally and at 3 mm on either side of the image paracentrally.
Results: :
Mean CCT was 1207µm (SD 69.7) pre-trephination and 672µm (SD 231.6) post-trephination. Following simple application and UVA crosslinking of the collagen gel mixture, the augmented material was tractionally adherent and of clarity and consistency similar to the surrounding cornea. Analysis of high resolution OCT images revealed the presence of a uniform layer filling the anterior stromal defect with a smooth anterior surface. Mean CCT after crosslinking was 1151µm (SD125.3), with the augmention layer having a mean thickness of 308µm (SD 102) centrally, and uniformly greater thicknesses of 357µm (SD 99.6) and 354.8µm (SD 104), paracentrally.
Conclusions: :
Photochemical corneal augmentation by the crosslinking of a collagen gel mixture within the site of lamellar dissection demonstrated good optical clarity, strong adhesive properties and a firm, uniformly shaped consistency. The new, photochemically enhanced collagen adequately replaced the dissected anterior stromal collagen to reconstruct and reshape ex-vivo corneas after a lamellar graft dissection. In-vivo wound healing studies are required to further characterize the potential clinical viability of this technology.
Keywords: refractive surgery: other technologies • protein structure/function