PURPOSE: To compare the effect of storing Descemet-stripping automated endothelial keratoplasty (DSAEK) tissue with anterior lamellar corneal tissue (ALCT)-on versus -off. METHODS: An in vitro model was used with corneoscleral rims and DSAEK quality paired corneas. After microkeratome-assisted excision of ALCT, 4 pairs of corneas (8 eyes) were stored with the ALCT left on the stroma (on) and the others with ALCT off the stroma (off) for 24 hours in Optisol GS solution. A vital dye assay was used to identify devitalized and necrotic endothelial cells with alizarin red S and trypan blue. RESULTS: Corneal endothelial cell damage was observed in the ALCT-off specimens, whereas almost no staining was observed in the ALCT-on samples. In addition, the ALCT-off donor corneas were clinically edematous and opaque, whereas the ALCT-on corneas were clear. Moreover, Descemet membranes of ALCT-off samples were found to be loose and easily detached from the stroma, with many Descemet striae observed in the specimens. CONCLUSIONS: This study shows that endothelial damage occurs in ALCT-off corneas. We hypothesize that the absence of the Bowman layer may contribute to the damage, because it has been shown that the Bowman layer provides a barrier function. These data suggest that it is important to keep the ALCT/Bowman layer on the stromal side of the DSAEK graft as long as possible to avoid stromal swelling and endothelial damage.
PURPOSE: To compare the effect of storing Descemet-stripping automated endothelial keratoplasty (DSAEK) tissue with anterior lamellar corneal tissue (ALCT)-on versus -off. METHODS: An in vitro model was used with corneoscleral rims and DSAEK quality paired corneas. After microkeratome-assisted excision of ALCT, 4 pairs of corneas (8 eyes) were stored with the ALCT left on the stroma (on) and the others with ALCT off the stroma (off) for 24 hours in Optisol GS solution. A vital dye assay was used to identify devitalized and necrotic endothelial cells with alizarin red S and trypan blue. RESULTS: Corneal endothelial cell damage was observed in the ALCT-off specimens, whereas almost no staining was observed in the ALCT-on samples. In addition, the ALCT-off donor corneas were clinically edematous and opaque, whereas the ALCT-on corneas were clear. Moreover, Descemet membranes of ALCT-off samples were found to be loose and easily detached from the stroma, with many Descemet striae observed in the specimens. CONCLUSIONS: This study shows that endothelial damage occurs in ALCT-off corneas. We hypothesize that the absence of the Bowman layer may contribute to the damage, because it has been shown that the Bowman layer provides a barrier function. These data suggest that it is important to keep the ALCT/Bowman layer on the stromal side of the DSAEK graft as long as possible to avoid stromal swelling and endothelial damage.