Improved storage methods for epikeratoplasty

A major variable in calculating the necessary curvatures and dimensions of the refractive lenticules for epikeratoplasty is the degree of swelling of the donor cornea during storage prior to lathing. The purpose of this study was to determine whether it is possible to restore donor corneas to their in vivo thickness using osmotic agents rather than physical means. The osmotic agents chosen were dextran and chondroitin sulfate. Donor porcine corneas stored in McCarey-Kaufman (MK) medium for seven days increased in thickness by almost 50%. Increasing concentrations of dextran and chondroitin sulfate, and increasing concentrations of dextran with 1.35% chondroitin sulfate added, were examined for their ability to reduce this thickness to normal levels. It was found that 15.00% dextran alone, and 10.00% dextran with 1.35% chondroitin sulfate, reduced corneal thickness to that of fresh tissue. Light and electron microscopy showed that the osmotic agents restored stromal ultrastructure to that of fresh tissue. The use of osmotic agents to reduce corneal thickness prior to lathing reduces physical deformation of the donor tissue associated with the use of a corneal press and may enhance the predictability of epikeratoplasty.