Ucak, Turgay; Uğurlu, Adem; İçel, Erel; Yilmaz, Hayati; Taşlı, Nurdan Gamze; Karakurt, Yucel; Demir, Mehmet

Objectives: Several methods of measuring central corneal thickness (CCT) have been compared, however, the data are still limited and conflicting. The aim of this study was to determine the agreement of CCT measurements performed in healthy eyes using ultrasound pachymetry (USP), non-contact tono/pachymetry, specular microscopy, biometry, Scheimpflug-based corneal topography, and optical coherence tomography (OCT).Methods: All of the participants underwent a complete ophthalmological examination. The CCT of all of the eyes included was measured using 6 different methods. The agreement between the methods was analyzed using the meandifference and Bland-Altman analysis based on a 95% limits of agreement.Results: A total of 64 patients with a mean age of 40.96±14.52 years (range: 20-78 years) were included in the study. The mean CCT value was 552.10±35.65 μm, 550.40±35.55 μm, 554.67±35.49 μm, 545.39±34.21 μm, 546.25±35.49 μm, and 552.64±33.59 μm using USP, non-contact tono/pachymetry, non-contact specular microscopy, biometry, Scheimpflugbased corneal topography, and OCT, respectively. The bias values determined by Bland-Altman plots were -1.70, -2.56,6.71, 5.85, and -0.53 for tono/pachymetry, specular microscopy, biometry, topography, and OCT, respectively. OCT demonstrated the lowest bias compared to USP. The overall intraclass correlation coefficient was 0.961 (range: 0.945-0.974) with a 95% confidence interval.Conclusion: All of the CCT measurements obtained using non-contact tono/pachymetry, non-contact specular microscopy, biometry, Scheimpflug-based corneal topography, and OCT were consistent with the USP measurements ofhealthy controls. Larger prospective studies to determine the interchangeability of different methods for CCT measurements in pathological conditions are warranted.

Cinici, E; Dilekmen, N; Kutlu, Z; Dincer, B; Cinici, O; Balta, H; Calik, I

Objectives: Carvacrol (CV) is a phenolic monoterpenoid found in the essential oil of a number of aromatic plants and herbs. The present study was an investigation of the potential protective effect of CV against paclitaxel (PTX)-induced retinal and optic nerve cytotoxicity in rats.Methods: A total of 18 adult male Wistar albino rats (250-400g) were randomized into 3 equal groups comprising 6 ani-mals each. Group 1 (control group) received intraperitoneal (IP) saline solution (0.5 mL/200 g) weekly for 4 weeks. Group 2 received an IP dose of PTX (5 mg/kg), and Group 3 received CV (25 mg/kg) 30 minutes after an IP dose of PTX (5 mg/kg) weekly for 4 weeks. At the conclusion of the experimental period, the retinal and optic nerve tissues of the subjects were evaluated histopathologically.Results: All of the retinal specimens in Group 1 (control) were histopathologically normal. In Group 2 (PTX), all of the eyes (6/6) revealed increased retinal vascularity and rosette-like structures in the outer nuclear layer, and in Group 3 (PTX-CV), all of the eyes (6/6) demonstrated normal retinal vascularity and the absence of rosette-like structures. All of the optic nerve specimens in Group 1 (control) were histopathologically normal. In Group 2 (PTX), all of the eyes (6/6) demonstrated severe vacuolization and a decreased number of astrocytes and oligodendrocytes in the optic nerve specimens, while 3 eyes (3/6) showed marked single cell necrosis. None of the eyes in Group 3 (PTX-CV) demonstrated either vacuolization or a reduction in the number of astrocytes and oligodendrocytes. No remarkable single cell necrosis was observed in the optic nerve specimens of Group 3 (PTX-CV).Conclusion: The histopathological findings indicated that CV played a protective role against PTX-induced cytotoxicity. CV might be a promising resource to counteract oxidative stress-based cytotoxicity in the field of retinal and optic nerve disorders.