Carotid artery blood flow is studied to compare models with rigid and elastic walls. Considering a patient-specific geometry and transient boundary conditions. In the case of rigid walls, only the fluid (blood) behavior is considered, in a typical Computational Fluid Dynamics study. With the elastic walls, the reciprocal influence of both fluid and solid (blood and artery) are taken into account, constituting a Fluid-Structure Interaction study. Furthermore, the study of the influence of mechanical properties of the artery, which become stiffer with the progression of atherosclerosis, on blood flow is also presented, an innovative approach relative to the work done in this field. Results show that the carotid sinus is the preferential zone to develop atherosclerosis, given its low values of Time-Averaged Wall Shear Stress. Additionally, it is fundamental to consider the arterial wall as elastic bodies, given that the rigid model overestimates the flow velocity and Wall Shear Stress. On the different mechanical properties of the vessel, its influence is minimal in the Time-Averaged Wall Shear Stress profiles. However, given the results of the displacement and velocity profiles, their inclusion in blood flow simulations in stenosed arteries should be considered.
Purpose: To assess the clinical outcomes and patient satisfaction of the Tecnis Eyhance, an advanced monofocal intraocular lens (IOL), compared to a conventional monofocal IOL. Design: Retrospective case-control study. Methods: This study included 120 eyes of 60 patients (30 patients in each group) who underwent bilateral cataract surgery either with the implantation of conventional monofocal IOLs (Tecnis PCB00), as a control group, or advanced monofocal IOLs (Tecnis Eyhance ICB00). Ophthalmological evaluation included the measurement of binocular corrected distance visual acuity (CDVA), monocular and binocular uncorrected distance visual acuity (UDVA), and uncorrected intermediate VA (UIVA). In addition the binocular defocus curve was analyzed. Furthermore a subjective questionnaire (Catquest-9SF) was used to assess vision and life quality. Results: The average binocular UDVA was 20/22 in the ICB00 group and 20/20 in the PCB00 model ( p = 0.62). The average monocular UIVA was 20/32 in the ICB00 group and 20/40 in the control group ( p < 0.001). We found the binocular UIVA, had a mean value of 20/30 in the ICB00, compared to 20/40 in the control group ( p < 0.001). The reported dysphotopsia was not significantly different between both groups ( p = 0.56). Regarding the life quality questionnaire, the ICB00 group showed less difficulty in activities requiring intermediate vision. Conclusion: Our results demonstrated a significant improvement in visual acuity for intermediate distance in the ICB00 group compared to the control group, without compromising distance visual acuity. We also found a greater capability for intermediate distance activities (namely for computer use and reading price tags) when comparing ICB00 patients with the control group.
Introduction and Objective
To evaluate corneal epithelial thickness (ET) and corneal thickness (CT) profiles in healthy eyes of Portuguese children and provide information to establish the first normative Caucasian database for these age group.
Methods
Sixty healthy eyes of 60 children aged between 8 and 18 were evaluated using the Cirrus high-definition optical coherence tomography device. The average ET and CT were assessed using Cirrus Review Software with predefined concentric corneal ring-shaped zones. Specific regions of ET (central, superior, inferior, temporal, nasal, superonasal, inferotemporal, superotemporal and inferonasal) were also assessed. The mean ET, the mean CT and the difference of ET in corresponding octants were compared by gender. Correlations between central epithelial thickness (CET), age and refractive error were evaluated.
Results and Discussion
The average ET was lower in the peripheric zones, whereas the average CT was higher. ET was thinner in the superior area than in the inferior (p<0.05). ET was thicker in boys than in girls (p<0.05), but CT did not differ. CET was not correlated with older age or refractive error.
Conclusion
Optical coherence tomography analysis of ET reveals that it is thinner in the periphery, where the CT is thicker. Unlike CT, ET seems to be influenced by gender. ET profile proved to be a useful tool in keratoconus diagnosis and subclinical keratoconus detection in adults. As epithelial changes occur early in the disease and keratoconus is more aggressive in pediatric population, a normative database of ET profile could contribute to enhance early recognition of the disease in this age group.
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