verification of donor lenticule appropriate orientation in dsaek surgery using double-ring sign

purpose: to describe a new noninvasive method to assure correct orientation of donor lenticules in descemet stripping automated endothelial keratoplasty (dsaek) surgery. methods: dsaek surgery was performed in three eyes with the diagnosis of pseudophakic bullous keratopathy (pbk). for the laboratory part of the study, two whole globes and two precut corneoscleral buttons were used. the donor lenticules were inserted in correct orientation and upside down orientation in the eye-bank globes. results: when anterior chamber was completely filled with air, two or more shiny rings were formed at the borders of donor lenticules because of total internal reflection in the graft. in both live and eye-bank eyes, the smoother larger thinner outermost ring which represented endothelial side of the grafts was formed deeper and the smaller thicker innermost ring which represented stromal side was formed more superficial when the grafts were attached in correct orientation,. when the lenticules were inserted upside down in the eye-bank eyes, a reverse situation was observed and the largest ring formed more superficial. conclusion: the double-ring sign can be used to assure the correct orientation of the donor lenticles at the end of the dsaek surgery.