Moreover, the crystalline lens tilted by approximately 4.16° ± 1.97° relative to the CV. However, the centers of the limbus and crystalline planes were not in the same quadrant in 80% of eyes (24/30). The distance of the center of the limbus plane relative to the CV was approximately 0.31 ± 0.14 mm, which approximated the distance of the center of the crystalline lens plane relative to the CV at 0.33 ± 0.20 mm (P = 0.354). The mean distance between the central points of crystalline lens plane and limbus plane was approximately 0.33 ± 0.18 mm. SS-OCT anterior segment images and 3D reconstructions were used for data analysis. Thirty consecutive patients with cataract (30 right eyes) were included in this prospective, observational, pilot case series study. To investigate crystalline lens tilt and decentration with respect to the corneal vertex (CV) using swept-source optical coherence tomography (SS-OCT) combined with three-dimensional (3D) reconstruction. The aberrometers showed more agreement at a pupil diameter of 6 mm compared to 4 mm. These results suggest that in healthy eyes, the two aberrometers may vary in some details. ![]() The iTrace and OPD Scan showed the largest number of differences for aberrations of internal optics rather than total aberrations for both pupil diameters. Aberrations of the internal optics showed significant differences in the mean values of total RMS, spherical aberration (Z4,0), and coma (Z3,-1) between the two devices (p<0.001, p=0.01, p<0.001). At a pupil diameter of 6 mm, the two instruments showed a similar number of total aberrations. Aberrations of the internal optics showed significant differences in the mean values of total RMS, coma (Z3,-1), and trefoil (Z3,3) between the iTrace and OPD Scan (p<0.001, p=0.01, p<0.001) for the same pupil diameter of 4 mm. These parameters, together with the refractive parameters, were then analyzed and complimented by paired t-tests.Īt a pupil diameter of 4 mm, the number of total aberrations in the entire eye showed significant differences for the mean values of spherical aberrations (Z4,0) obtained with the OPD Scan and iTrace aberrometers (p=0.001). For each aberrometer and each eye, the averaged Zernike data were used to calculate various root-mean-square (RMS) data. Aberrations of internal optics and total aberrations were compared for the two aberrometers. We compared the aberrations obtained from measurements obtained at pupillary diameters of 4 mm and 6 mm with the OPD Scan and iTrace. Following pupil dilation, aberrations were measured with the iTrace and OPD Scan. Our experts achieve insight using an array of techniques such as nuclear magnetic resonance (NMR), GPC, ICP and XRF to determine the composition of materials such as PET, as part of recycled plastics analysis.To compare and evaluate the total and internal aberrations measured by two aberrometers: the laser ray tracing aberrometer (iTrace, Tracey Technology) and the automatic retinoscope aberrometer (OPD Scan, Nidek).Ī total of 54 healthy eyes were enrolled in the study. Our team of experts can support you with troubleshooting, process optimization and problem solving activities regarding the processing of your PET materials. Intertek chemists have years of experience in analyzing PET packaging materials, using a wide range of analytical and physical testing techniques. Polyethylene terephthalate (PET) and recycled PET (rPET) materials are known for their durability and versatility and are accordingly analysed for many reasons, for example to discover if the material has been previously recycled, and if so, how many times, to confirm its Molecular Weight, and to discover its purity, for example regarding presence of heavy metals ![]() Physical and chemical laboratory analyses on PET and recycled PET materials to determine their characteristics and composition Polyethylene terephthalate (PET) and recycled PET Packaging Testing
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