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C. Wiaux, F. Majo, P. Othenin–Girard, S. Uffer; Unintentional Inversion of Human Corneal Button During Penetrating Keratoplasty : A Transmission Electronic Microscopic Analysis . Invest. Ophthalmol. Vis. Sci. 2005;46(13):4530.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To study the survival of the epithelial and endothelial cells of a human corneal graft after an unintentional inversion during Penetrating Keratoplasty. Methods: One year after a corneoscleral laceration, a 37 year old man received a 7.5mm corneal graft. Stromal folds and persistent corneal oedema with poor visual acuity, lead to a second penetrating keratoplasty twenty–two months later. Corneal button was examined by light microscopy (LM), and the corneal inversion was confirmed by the Periodic Acid Schiff (PAS) positive coloration of Descemet’s layer. By transmission electronic microscopy (TEM), we analyzed the ultrastructural features of the cells situated on the external and internal corneal button surfaces. Results: LM: PAS positive fragments of Descemet’s membrane were observed on the external surface. A pluristratified epithelium covered the external surface and a single layer of cells covered the internal side of the corneal button. TEM: On the external surface, recipient basal corneal epithelial cells were fixed to the donor posterior stroma with few hemidesmosomes. This pluristratified epithelium exhibited normal corneal epithelial characteristics. In the stroma, keratocytes were vacuolized and collagen lamellae were dissociated. On the internal side of the corneal button, Bowman’s layer exhibited normal features. The total internal surface was covered with abnormal endothelial cells. Their thickness was only half that of a normal endothelial cell, lateral interdigitations were missing as well as posterior villosities. Between the endothelial cells and the Bowman’s layer a neo basal lamina was observed and was up to one thousand times thicker than normal. However, endothelial cells exhibited normal cytoplasmic features. Conclusions: The total external surface of the button is covered by recipient corneal epithelial cells. These epithelial cells resting on the corneal posterior donor stroma express less hemidesmosomes. No donor epithelial cells survived in the anterior chamber. The presence of abnormal endothelial cells on the totality of the internal surface can be explained by two mechanisms: recipient endothelial cells can colonise the entire corneal button and migrate on Bowman’s membrane on a distance of at least 3.75 mm, or donor epithelial cells can differentiate in endothelial cells in the anterior chamber environment.
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