In eyes with normal corneas, DCT allows suitable and reliable IOP measurements which are in good concordance with GAT. Comparison of DCT with intracameral manometry is desirable in the future.
Short- and long-term reproducibility of DCT is comparable to that of GAT. GAT is more affected by CCT than DCT, measuring higher IOPs in eyes with higher central corneal thickness.
In cases with higher difference between DCT-GAT, the difference is reproducible and even present in the fellow eye. We, therefore, assume that the differences are not caused by chance, but by differing biomechanical corneal properties.
Thirty healthy volunteers were nasally exposed to control air and urban dust (SRM 1649a) in concentrations of 150 and 500 microg/m3 for 3 hours. Thirty minutes, 8 hours, and 24 hours after exposure, nasal cytologies were obtained, and nasal secretion levels of interleukin (IL)-1beta, IL-6, IL-8, tumor necrosis factor-alpha, epithelial neutrophil activating protein-78, monocyte chemoattractant protein-1, and substance P were determined. Twenty-four hours after exposure to 500 microg/m3, nasal secretion levels of IL-1beta increased 72.3% (0-150.2%, P=0.002), levels of IL-6 increased 42.2% (-28-161.9%,P=0.01), and levels of IL-8 increased 19.7% (-20.3-60.5%, P=0.03; median and 95% confidence interval). These cytokines correlated closely with nasal inflammatory cell counts. No exposure-related changes of tumor necrosis factor-alpha, monocyte chemoattractant protein-1, epithelial neutrophil activating protein-78, and substance P levels were observed. These results provide experimental support for recent epidemiological observations that short-term increase of outdoor particulate matter concentration increases the frequency of upper respiratory diseases.
Purpose: To investigate the corneal hysteresis (CH), the corneal resistance factor (CRF) and the corneal compensated intraocular pressure (IOPcc) of subjects with normal corneas and with corneal pathologies with the Ocular Response Analyzer (ORA).
Methods: IOP was measured using Goldmann applanation tonometry (GAT), dynamic contour tonometry (DCT) and ORA in 102 subjects with normal corneas and in patients with keratoconus (KC, n=32), Fuchs endothelial corneal dystrophy (FD, n=34) and penetrating keratoplasty (KP, n=50). Additionally central corneal thickness (CCT) and CH were quantified.
Results: CH and CRF were significantly reduced in all groups with corneal pathologies in comparison to the normal group (CH: 7.7 (KC), 8.9 (KP), 7.3 (FD) versus 10.3 (N), CRF: 6.4 (KC), 9.3 (KP), 8.2 (FD) versus 10.8 (N) mmHg). High significant differences were also observed in mean IOP between the control group and the groups with corneal pathologies. There was a significant correlation between CH and CCT for normal corneas and corneas with KC and KP.
Conclusions: CH and CRF are significantly decreased in patients with KC, FD and KP compared to subjects with normal corneas. Patients with corneal pathologies showed a substantial variability of mean IOP‐values evaluated by using different methods of IOP‐measurement in comparison to subjects with normal corneas suggesting that corneal properties strongly influence the validity of IOP‐measurements.
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