Galilei Corneal Tomography for Screening of Refractive Surgery Candidates: A Review of the Literature, Part II

Corneal topography is the most widely used technology for examining the anterior corneal surface. Scheimpflug imaging is a newer technique that allows for measurement of both the anterior and posterior corneal surface, which allows for three-dimensional reconstruction of the cornea. This is of particular interest and value in the field of cataract and refractive surgery. The Galilei camera is a commercially available dual Scheimpflug system that combines curvature data from Placido disc-based corneal topography with elevation data from Scheimpflug technology. The addition of Placido disc topography makes the Galilei unique from its more popular counterpart, the Pentacam, which was discussed in Part I. Compared to the Pentacam, and however, the Galilei analyzer is a newer system that has emerged as a valuable screening tool given its dual Scheimpflug capability. In the first article of this series, the authors summarized the refractive indices available on the Pentacam system with the purpose of identifying the best diagnostic parameters for keratoconus. Similarly, the purpose of this article is to summarize corneal surface indices available on the Galilei system and evaluate their use in screening of the refractive surgery candidate. Since post-operative keratectasia is still prevalent, this paper aims to identify the most clinically relevant indices that may be used in pre-operative evaluation

Advances in Biomechanical Parameters for Screening of Refractive Surgery Candidates: A Review of the Literature, Part III

Corneal biomechanical properties have garnered significant interest in their relation to the development of ectatic corneal disease. Alongside the advent of corneal tomography and Scheimpflug imaging such as Pentacam and Galilei, there have been advances in assessing the cornea based on its biomechanical characteristics. Though the aforementioned imaging systems are highly capable of identifying morphologic abnormalities, they cannot assess mechanical stability of the cornea. This article, in contrast to Parts I and II of this article series, will focus on in vivo corneal biomechanical imaging systems. The two most readily available commercial systems include the Corvis ST and the Ocular Response Analyzer. Both of these systems aimed to characterize corneal biomechanics via distinct measurements. While in Parts I and II of this article series the authors focused on elevation, pachymetric, and keratometric data, the purpose of this article was to summarize biomechanical parameters and their clinical use in screening refractive surgery candidates. Moreover, this article explores biomechanical decompensation and its role in the development of corneal ectasia and keratoconus. There is a focus on the diagnostic accuracy of biomechanical indices in the identification of diseases such as keratoconus that may preclude a patient from undergoing refractive surgery

The relationship between the systemic inflammatory response, tumour proliferative activity, T-lymphocytic and macrophage infiltration, microvessel density and survival in patients with primary operable breast cancer

The significance of the inter-relationship between tumour and host local/systemic inflammatory responses in primary operable invasive breast cancer is limited. The inter-relationship between the systemic inflammatory response (pre-operative white cell count, C-reactive protein and albumin concentrations), standard clinicopathological factors, tumour T-lymphocytic (CD4+ and CD8+) and macrophage (CD68+) infiltration, proliferative (Ki-67) index and microvessel density (CD34+) was examined using immunohistochemistry and slide-counting techniques, and their prognostic values were examined in 168 patients with potentially curative resection of early-stage invasive breast cancer. Increased tumour grade and proliferative activity were associated with greater tumour T-lymphocyte (P<0.05) and macrophage (P<0.05) infiltration and microvessel density (P<0.01). The median follow-up of survivors was 72 months. During this period, 31 patients died; 18 died of their cancer. On univariate analysis, increased lymph-node involvement (P<0.01), negative hormonal receptor (P<0.10), lower albumin concentrations (P<0.01), increased tumour proliferation (P<0.05), increased tumour microvessel density (P<0.05), the extent of locoregional control (P<0.0001) and limited systemic treatment (Pless than or equal to0.01) were associated with cancer-specific survival. On multivariate analysis of these significant covariates, albumin (HR 4.77, 95% CI 1.35–16.85, P=0.015), locoregional treatment (HR 3.64, 95% CI 1.04–12.72, P=0.043) and systemic treatment (HR 2.29, 95% CI 1.23–4.27, P=0.009) were significant independent predictors of cancer-specific survival. Among tumour-based inflammatory factors, only tumour microvessel density (P<0.05) was independently associated with poorer cancer-specific survival. The host inflammatory responses are closely associated with poor tumour differentiation, proliferation and malignant disease progression in breast cancer

Risk factors for recurrence in patients with Clostridium difficile infection due to 027 and non-027 ribotypes

Objectives: Our objective was to evaluate factors associated with recurrence in patients with 027+ and 027– Clostridium difficile infection (CDI). Methods: Patients with CDI observed between January and December 2014 in six hospitals were consecutively included in the study. The 027 ribotype was deduced by the presence of tcdB, tcdB, cdt genes and the deletion Δ117 in tcdC (Xpert® C. difficile/Epi). Recurrence was defined as a positive laboratory test result for C. difficile more than 14 days but within 8 weeks after the initial diagnosis date with reappearance of symptoms. To identify factors associated with recurrence in 027+ and 027– CDI, a multivariate analysis was performed in each patient group. Subdistributional hazard ratios (sHRs) and 95% confidence intervals (95%CIs) were calculated. Results: Overall, 238 patients with 027+ CDI and 267 with 027– CDI were analysed. On multivariate analysis metronidazole monotherapy (sHR 2.380, 95%CI 1.549–3.60, p <0.001) and immunosuppressive treatment (sHR 3.116, 95%CI 1.906–5.090, p <0.001) were factors associated with recurrence in patients with 027+ CDI. In this patient group, metronidazole monotherapy was independently associated with recurrence in both mild/moderate (sHR 1.894, 95%CI 1.051–3.410, p 0.033) and severe CDI (sHR 2.476, 95%CI 1.281–4.790, p 0.007). Conversely, non-severe disease (sHR 3.704, 95%CI 1.437–9.524, p 0.007) and absence of chronic renal failure (sHR 16.129, 95%CI 2.155–125.000, p 0.007) were associated with recurrence in 027– CDI. Conclusions: Compared to vancomycin, metronidazole monotherapy appears less effective in curing CDI without relapse in the 027+ patient group, independently of disease severity

Mechanisms of Optical Regression Following Corneal Laser Refractive Surgery: Epithelial and Stromal Responses

Laser vision correction is a safe and effective method of reducing spectacle dependence. Photorefractive Keratectomy (PRK), Laser In Situ Keratomileusis (LASIK), and Small-Incision Lenticule Extraction (SMILE) can accurately correct myopia, hyperopia, and astigmatism. Although these procedures are nearing optimization in terms of their ability to produce a desired refractive target, the long term cellular responses of the cornea to these procedures can cause patients to regress from the their ideal postoperative refraction. In many cases, refractive regression requires follow up enhancement surgeries, presenting additional risks to patients. Although some risk factors underlying refractive regression have been identified, the exact mechanisms have not been elucidated. It is clear that cellular proliferation events are important mediators of optical regression.  This review focused specifically on cellular changes to the corneal epithelium and stroma, which may influence postoperative visual regression following LASIK, PRK, and SMILE procedures

Complex nanostructures in diamond

Meteoritic diamonds and synthesized diamond-related materials contain a wide variety of complex nanostructures. This Comment highlights and classifies this structural complexity by a systematic hierarchical approach, and discusses the perspectives on nanostructure and properties engineering of diamond-related materials

Pentacam® Corneal Tomography for Screening of Refractive Surgery Candidates: A Review of the Literature, Part I

Corneal tomography and Scheimpflug imaging are frequently used to analyze the corneal surface, especially in the field of cataract and refractive surgery. The Pentacam system is one of the most commonly used commercially available systems for this purpose. Through a rotating Scheimpflug camera, the system is capable of creating a three-dimensional map of the cornea. These advances in tomography have simultaneously enhanced the ability of clinicians to screen surgical candidates and detect subtle corneal changes in diseases such as keratoconus. However, there remains a need to enhance diagnosis in order to recognize mild and early forms of corneal ectasia. As iatrogenic ectasia and keratoconus are dreaded complications of refractive surgery, it is imperative to screen patients appropriately prior to surgery. The Pentacam is one of many systems utilized in the screening process, but the literature has not identified specific protocol nor parameters that are capable of carrying out this process appropriately. Post-operative keratoconus continues to occur despite the advances in technology seen in corneal imaging. Therefore, clear indices for screening are required in order to diagnose early forms of keratoconus and other corneal diseases that may exclude the seemingly asymptomatic patient from undergoing refractive surgery. This article aims to summarize the indices available on the Pentacam system and to identify the most accurate parameters for screening of the refractive surgery candidate

Cooling history and emplacement of a pyroxenitic lava as proxy for understanding Martian lava flows

Terrestrial analogues are often investigated to get insights into the geological processes occurring on other planetary bodies. Due to its thickness and petrological similarities, the pyroxenitic layer of the 120m-thick magmatic pile Theo’s Flow (Archean Abitibi greenstone belt Ontario, Canada), has always been regarded as the terrestrial analogue for Martian nakhlites. However, its origin and cooling history and, as a consequence those of nakhlites, have always been a matter of vigorous debate. Did this lava flow originate from a single magmatic event similar to those supposed to occur on Mars or do the different units derive from multiple eruptions? We demonstrate, by a combination of geothermometric constraints on augite single crystals and numerical simulations, that Theo’s Flow has been formed by multiple magma emplacements that occurred at different times. This discovery supports the idea that the enormous lava flows with similar compositions observed on Mars could be the result of a process where low viscosity lavas are emplaced during multiple eruptions. This has profound implications for understanding the multiscale mechanisms of lava flow emplacement on Earth and other planetary bodies