In this Letter, we demonstrate quantitative phase imaging of biological samples, such as human red blood cells (RBCs) and onion cells using narrow temporal frequency and wide angular frequency spectrum light source. This type of light source was synthesized by the combined effect of spatial, angular, and temporal diversity of speckle reduction technique. The importance of using low spatial and high temporal coherence light source over the broad band and narrow band light source is that it does not require any dispersion compensation mechanism for biological samples. Further, it avoids the formation of speckle or spurious fringes which arises while using narrow band light source.
BACKGROUND/AIMS:The purpose of this study was to compare and evaluate the visual outcome and complications of various techniques of secondary intraocular lens (IOL) (i.e., anterior chamber IOL [ACIOL], suture-fixated posterior chamber IOL [PCIOL], and glue-fixated PCIOL).STUDY DESIGN AND SETTING:This was a randomized, prospective, interventional, comparative, clinical trial study.SUBJECTS AND METHODS:Patients of either sex having aphakia and lacking posterior capsular support were included in the study, and patients having corneal or scleral pathology, optic atrophy, uncontrolled glaucoma, retinal detachment, and other retinal pathology were excluded from the study. The patients were divided into three groups after comprehensive ophthalmological examination – Group A (secondary ACIOL) included 44 patients, Group B (secondary scleral-fixated sutured PCIOL) included 32 patients, and Group C (fibrin glue-fixated sutured PCIOL) included 34 patients.RESULTS:A total of 110 patients were included in this study, of which 59 (53.63%) were males and 51 (46.37%) were females. The best-corrected visual acuity (VA) after 6 weeks was in the range of 20/60–20/40 in 36.4% of Group A and 40.6% of Group B patients. In Group C, 52.9% of patients had best-corrected VA in the range of 20/30–20/20. The overall complications were less in glued PCIOL group.CONCLUSION:It can be concluded that fibrin glue-assisted PCIOL implantation provides better visual outcome with minimal complications in eyes with deficient capsular support.
Abstract:We suggest a new multimodal imaging technique for quantitatively measuring the integral (thickness-average) refractive index of the nuclei of live biological cells in suspension. For this aim, we combined quantitative phase microscopy with simultaneous 2-D fluorescence microscopy. We used 2-D fluorescence microscopy to localize the nucleus inside the quantitative phase map of the cell, as well as for measuring the nucleus radii. As verified offline by both 3-D confocal fluorescence microscopy and 2-D fluorescence microscopy while rotating the cells during flow, the nucleus of cells in suspension that are not during division can be assumed to be an ellipsoid. The entire shape of a cell in suspension can be assumed to be a sphere. Then, the cell and nucleus 3-D shapes can be evaluated based on their in-plain radii available from the 2-D phase and fluorescent measurements, respectively. Finally, the nucleus integral refractive index profile is calculated. We demonstrate the new technique on cancer cells, obtaining nucleus refractive index values that are lower than those of the cytoplasm, coinciding with recent findings. We believe that the proposed technique has the potential to be used for flow cytometry, where full 3-D refractive index tomography is too slow to be implemented during flow. References and links 1. C. M. Vest, Holographic Interferometry (Wiley, New York, 1979). 2. N. T. Shaked, "Quantitative phase microscopy of biological samples using a portable interferometer," Opt. Lett. Marquet, "Cell morphology and intracellular ionic homeostasis explored with a multimodal approach combining epifluorescence and digital holographic microscopy,"
We report multispectral phase-shifting interference microscopy for quantitative phase imaging of human red blood cells (RBCs). A wide range of wavelengths are covered by means of using multiple color light emitting diodes (LEDs) with narrow spectral bandwidth ranging from violet to deep red color. The multicolor LED light source was designed and operated sequentially, which works as a multispectral scanning light source. Corresponding to each color LED source, five phase-shifted interferograms were recorded sequentially for the measurement of phase maps, as well as the refractive index of RBCs within the entire visible region. The proposed technique provides information about the effect of wavelengths on the morphology and refractive index of human RBCs. The system does not require expensive multiple color filters or any wavelength scanning mechanism along with broadband light source.
We present a new technique for obtaining simultaneous multimodal quantitative phase and fluorescence microscopy of biological cells, providing both quantitative phase imaging and molecular specificity using a single camera. Our system is based on an interferometric multiplexing module, externally positioned at the exit of an optical microscope. In contrast to previous approaches, the presented technique allows conventional fluorescence imaging, rather than interferometric off-axis fluorescence imaging. We demonstrate the presented technique for imaging fluorescent beads and live biological cells.
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