[Comparison of I Care rebound tonometer and Goldmann applanation tonometer after Descemet's stripping with automated endothelium keratoplasty].

OBJECTIVE: To evaluate the influence of corneal thickness (CT) on the intraocular pressure (IOP) measurements, the agreement of IOP readings with I Care rebound tonometer (RBT) and Goldmann applanation tonometer (GAT), and the agreement of central and peripheral IOP values obtained by RBT. METHODS: Thirty-seven eyes of 34 patients after Descemet's stripping with automated endothelium keratoplasty (DSAEK) underwent CT measurement using anterior segment OCT (AS-OCT) followed by IOP evaluation with the GAT at corneal center and with the RBT at corneal center and at 1 mm from the limbus in the nasal and temporal directions. The mean IOP measurement by the RBT and measurement by the GAT were analysed by paired t test. Pearson correlation analysis were performed to assess the correlations between the measurement and the influence of CT on IOP values. Agreement between the tonometers was calculated using the Bland-Altman method. RESULTS: IOP obtained by GAT was (16.2 ± 4.7) mm Hg (1 mm Hg = 0.133 kPa), and IOP obtained from central cornea, nasal cornea and temporal cornea by RBT were (16.0 ± 5.3) mm Hg, (17.4 ± 5.0) mm Hg and (17.1 ± 5.0) mm Hg, respectively. There was no statistical difference between the IOP on central cornea obtained by GAT and RBT (t = 0.77, P = 0.446), IOP on the peripheral cornea were higher than on central cornea by RBT (t = 3.24, 3.17, P = 0.003), and they were positively correlated (r = 0.869, 0.911, P < 0.05). The IOP readings showed positive relationship to CT values. Bland-Altman scatter plots showed reasonable inter-method agreement between each technique of IOP measurements. CONCLUSIONS: After DSAEK, the IOP readings obtained by RBT or GAT show positive relationship to CT values. There are reasonable agreements between each technique of IOP measurements. Considering the special advantages, RBT is an effective method to observe the IOP changes after DSAEK.

[Experimental study on repairing damage of corneal surface by mesenchymal stem cells transplantation].

OBJECTIVE: To investigate the survival, migration and differentiation of the cultured human mesenchymal stem cells derived from bone marrow (hMSCs) after transplanted onto the alkaline burn rabbit cornea. METHODS: Alkaline burn on rabbit corneas was induced with NaOH solution. One month later, hMSCs cultured with a feeding of amniotic membrane were transplanted onto the surface of alkaline burn rabbit corneas. Amniotic membrane alone transplantation was used at the same time as control group. One month after transplantation, the changes of corneal morphology were analyzed by clinical observations and HE staining. Immunohistochemistry was carried out with the antibodies against human nuclei and cytokeratin 12 to investigate the distribution and differentiation of hMSCs. RESULTS: The rabbit cornea became totally opaque one month after alkaline burn. Blood vessels could be seen within the superficial layer and stroma. The surface of cornea was rough and dry. There were many goblet cells found in the corneal epithelial layer. One month after transplantation of hMSCs, the surface of alkaline burn cornea became smoother. The amount of the new blood vessels of the cornea reduced and the goblet cells disappeared. Anti-human nuclei antibody staining showed positive cells on the surface layer and superficial stroma while cytokeratin 12 positive cells were only present in the epithelium layer. In the amniotic membrane transplantation control group, no clinical improvement of the cornea was found. Goblet cells were still seen on the corneal surface. Both anti-human nuclei antibody and cytokeratin 12 staining were negative. CONCLUSIONS: hMSCs survive and migrate to stroma after transplanted onto the surface of alkaline burn rabbit cornea. No rejection is detected. hMSCs on the corneal surface differentiate to corneal epithelium, where those migrated to the stroma differentiate to cells other than epithelium. hMSCs transplantation decrease corneal conjunctivization after alkaline burn.