Over time, the cornea in some individuals can become hazy as result of injury or slowly progressing disease. This haziness occurs as a result of damage to a thin, delicate layer of cells in the cornea called the endothelium. As a result, vision becomes hazy and blurred. Previously, the only treatment option was to transplant the entire thickness of the cornea. Modern surgical techniques only remove the damaged layer of the cornea. Known as DSEK, or, Descemet's Stripping Endothelial Keratoplasty, this technique has significantly reduced recovery times and improved vision compared to conventional corneal transplant surgery. The procedure involves gently removing the thin damaged layer out of the eye. The donor tissue is folded and inserted into the eye. An air bubble is then used to carefully unfold the donor tissue. The air bubble helps to secure the donor tissue to the eye. Initially, vision will be blurred, however, as the bubble absorbs vision will improve significantly. In some cases, the donor tissue can loosen and detach. In this case, the bubble will need to be applied in order to reattach the donor tissue to the eye.