Separation of corneal stroma and Descemet's membrane during deep lamellar keratoplasty

Purpose. To study the interface of the corneal stroma and Descemet's membrane and to report the histologic findings of the deep corneal stromal tissue removed during deep lamellar keratoplasty (DLKP). Methods. The deep stromal tissues of four corneas were removed during DLKP and were examined histologically by light microscopy (LM) and transmission electron microscopy (TEM). Results. Descemet's membrane appeared as a smooth surface under the surgical microscope during the removal of deep corneal stroma. Two of the four excised tissues showed a thin layer attachment to the deep stromal tissue by LM and TEM. The layer measured approximately 3.0 to 4,0 mum and as observed as a striated structure attached to the stromal tissue of both specimens. The other two specimens contained only stromal tissue. Conclusions. Separation of the deep stromal tissue from Descemet's membrane may occur within the Descemet's membrane, and the separation is probably between the anterior banded and the posterior nonbanded layer of Descemet's membrane in some cases during DLKP. The lamellar structure of the delaminated region suggests a mechanically weak segment of Descemet's membrane. The smooth surface of Descemet's membrane observed under a surgical microscope is not the actual interface of corneal stroma and Descemet's membrane.