Biomechanical diagnosis of keratoconus: evaluation of the keratoconus match index and the keratoconus match probability

Purpose:  To evaluate the diagnostic capacity of the Ocular Response Analyser’s keratoconus match index (KMI) and keratoconus match probability (KMP) classification in a sample of keratoconus (KC) patients. Methods: Keratoconus match index and KMP from 114 KC eyes, randomly selected from 114 patients with bilateral keratoconus (KCG), were compared with the corresponding ones from 109 normal eyes (CG). Keratoconus match index’s predictive accuracy was assessed by receiver operating curves (ROC). Keratoconus match probability level of agreement was evaluated at the different KC stages of the Amsler–Krumeich classification. Correlations were estimated with topographic keratoconus classification (TKC), keratoconus index (KI), index of surface variance (ISV), vertical asymmetry (IVA), height asymmetry (IHA), height decentration (IHD), minimal radius (Rmin), central corneal thickness (CCT), thinnest corneal thickness (TCT) mean keratometry (Km) and intraocular pressure (IOPg). Results: Mean KMI in KCG and CG was 0.20 ± 0.38 and 0.98 ± 0.25, respectively (p < 0.01). Significant KMI differences (p < 0.01) were detected in different KC groups [range: 0.62 ± 0.38 (KC 1), ?0.62 ± 0.04 (KC 4)]. Significant correlation was detected between KC staging and KMI (r = ?0.56, p < 0.0001). Keratoconus match probability identified 22.03% of the CG eyes as suspect. Moreover, KMP identified 7.01% and 23.68% of the KCG eyes as normal and suspect, respectively. Receiver operating curves analysis for KMI parameter indicated a predictive accuracy of 97.7% (cut‐off point: 0.512, sensitivity: 91.18%, specificity: 94.34%). Conclusions: Keratoconus match index seems to be a reliable index in keratoconus diagnosis and staging. Keratoconus match probability identifies a significant percentage of topographically defined KC and CG eyes as suspect. Diagnostic capacity of these novel indexes needs to be further explored.     

Biomechanical profile of the cornea in primary congenital glaucoma

Purpose: The aim of our study was to investigate the biomechanical properties of the cornea in primary congenital glaucoma (PCG) and to identify the potential ocular determinants, which affect the corneal biomechanical metrics. Methods: Corneal hysteresis (CH), corneal resistance factor (CRF) and central corneal thickness (CCT) were measured in 26 patients with PCG (40 eyes) with the aid of ocular response analyser. In vivo laser‐scanning confocal microscopy was used for the estimation of stromal keratocyte density (KD) and the evaluation of corneal endothelium. Twenty normal subjects (40 eyes) served as controls. Student’s t‐test and Pearson’s correlation coefficients were used for statistical analysis. p Values <0.05 were considered statistically significant. Results: Corneal hysteresis, CRF and CCT were significantly reduced in patients with PCG (all p < 0.05). Corneal hysteresis and CRF negatively correlated with the corneal diameter in both groups (r₁ = ?0.53, r₂ = ?0.66, p < 0.001 for CH and r₁ = ?0.61, r₂ = ?0.69, p < 0.001 for CRF). Moreover, we identified a significant correlation between CH and CRF with CCT in both groups (r₁ = 0.51, r₂ = 0.48, p < 0.001 for CH and r₁ = 0.45, r₂ = 0.44, p < 0.001 for CRF). Mean KD was significantly reduced both in the anterior and posterior corneal stroma in patients with PCG (764 ± 162 and 362 ± 112 cells/mm², respectively) compared with controls (979 ± 208 and 581 ± 131 cells/mm², respectively) (p < 0.001). There was no significant correlation between the keratocyte density in anterior and/or posterior stroma and CH or CRF in any group (r₁ = 0.29, r₂ = 0.31, p < 0.06). Mean endothelial cell density was also significantly reduced in PCG group (2920 ± 443 cells/mm²) compared with control group (3421 ± 360 cells/mm²) (p < 0.001). Pleomorphism and polymegalism were significantly increased in corneal endothelium of patients with PCG. Conclusions: Our results showed a significant reduction in CH and CRF in PCG. Both CH and CRF were negatively correlated with corneal diameter. A significant correlation of CH and CRF with CCT was identified in both groups. Keratocyte density was decreased in PCG, but did not have a significant impact on CH and CRF. Mean endothelial density was also decreased in PCG. Our results suggest that reduced CCT and increased corneal diameter are major ocular determinants for the modified corneal biomechanical profile in PCG, while cellular alterations in corneal stroma and endothelium have no significant biomechanical impact.     

Is rotation the mode of failure in pertrochanteric fractures fixed with nails? Theoretical approach and illustrative cases

European Journal of Orthopaedic Surgery & Traumatology - The present article reviews data from biomechanical and clinical studies which indicate that rotational instability can cause failure of...     

Expression of cyclins D1, D3 and p27 in thymic epithelial tumors

In this study, the expression of cyclins D1 and D3, as well as cyclin-dependent kinase inhibitor p27 in thymic epithelial tumors (thymomas) is examined. Histological specimens from 24 patients (11 males and 13 females) were submitted to classification according to WHO criteria. Staining for cyclins D1, D3 and p27 was applied and evaluation was performed for expression of D1, D3 and p27. Eighteen patients presented low-grade thymomas (nine B1, predominantly cortical; three B2, cortical; six B3, well-differentiated thymic carcinoma) and six patients benign thymomas (four A-medullary, two AB-mixed). The p27 expression in patients with benign thymomas was 42+/-26%, whereas in patients with low-grade thymoma, it was 11+/-13%. The expression of cyclins D1 and D3 was 2.8+/-2.7 and 10+/-6% for benign as well as 8.3+/-9.6 and 12+/-10% for low-grade thymomas, respectively. A statistically significant difference was revealed regarding the p27 expression through different grades (analysis of variance P-value 0.00076) and histopathological types of thymomas (P=0.0047). This finding of greater p27 expression in benign thymomas with progressive reduction in higher grades is compatible with observations on other soft tissue and solid tumors suggesting that p27 level decreases during tumor development and progression.     

Unilateral pulmonary oedema due to lung re-expansion following pleurocentesis for spontaneous pneumothorax. The role of non-invasive continuous positive airway pressure ventilation

Re-expansion pulmonary oedema represents a rare complication of treatment of spontaneous pneumothorax with only a few cases documented in the current literature. We present the case of a 47-year-old male who presented a right-sided spontaneous pneumothorax and developed respiratory failure after chest tube drainage. The diagnosis of re-expansion pulmonary oedema was made and he was successfully treated with non-invasive continuous positive airway pressure ventilation. Since pathogenesis of re-expansion unilateral pulmonary oedema differs significantly from that of cardiogenic pulmonary oedema, the role of non-invasive continuous positive airway pressure ventilation is discussed as an additional therapeutic option.     

Evaluation of the efficacy of the Allegretto Wave and the Wavefront-optimized ablation profile in non-anterior astigmatisms

Purpose: To assess the efficacy of the Allegretto Wave and the wavefront-optimized ablation profile (WFO) in non-anterior astigmatism correction, in both LASIK and photorefractive keratectomy (PRK) treatments. Methods: Seventy-four refractive surgery candidates were recruited prospectively in a non-randomized trial. Only one eye from each candidate was randomly enrolled in the study. Of them, 40 eyes underwent LASIK treatment (LG group), while 34 eyes underwent PRK treatment (PG group). Preoperatively, the ocular residual astigmatism (ORA) was calculated for each eye, according to which each astigmatism fault was characterized as primarily anterior or non-anterior. Twenty LG eyes and 16 PG eyes presented primarily anterior astigmatism (LG-A and PG-A subgroups, respectively), while 20 LG eyes and 18 PG eyes demonstrated primarily non-anterior astigmatism (LG-NA and PG-NA subgroups, respectively). Postoperatively, vector analysis of astigmatism correction was conducted. The following indexes were calculated: (i) correction index (CI), (ii) difference vector (DV) and (iii) index of success (IOS). Results: Preoperatively, mean differences between manifest and topographic astigmatisms for the LG and the PG subgroups were significant (p:0.006 and p?相似文献