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Biomedical planar imaging using gamma radiation is a very important screening tool for medical diagnostics. Since lens imaging is not available in gamma imaging, the current methods use lead collimator or pinhole techniques to perform imaging. However, due to ineffective utilization of the gamma radiation emitted from the patient's body and the radioactive dose limit in patients, poor image signal to noise ratio (SNR) and long image capturing time are evident. Furthermore, the resolution is related to the pinhole diameter, thus there is a tradeoff between SNR and resolution. Our objectives are to reduce the radioactive dose given to the patient and to preserve or improve SNR, resolution and capturing time while incorporating three-dimensional capabilities in existing gamma imaging systems. The proposed imaging system is based on super-resolved time-multiplexing methods using both variable and moving pinhole arrays. Simulations were performed both in MATLAB and GEANT4, and gamma single photon emission computed tomography (SPECT) experiments were conducted to support theory and simulations. The proposed method is able to reduce the radioactive dose and image capturing time and to improve SNR and resolution. The results and method enhance the gamma imaging capabilities that exist in current systems, while providing three-dimensional data on the object.

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In this research, we present a novel device that solves the reduced visual acuity caused by involuntary movements of the retina in nystagmus. The proposed solution comprises a contact lens that moves together with the eyeball and an ophthalmic lens (spectacles). Our work has three parts: numerical simulation of the proposed solution, an experimental optical bench procedure, and a clinical experiment, with nonnystagmus subjects, in which we mimicked the uncontrolled eye movements in nystagmus. In the numerical and experimental bench sections of this study, we show that the proposed optics produces a clear and stable image on a screen. In the clinical study, subjects with the device felt only small movements of the image when they moved their eyes across the field of view. They described a magnification resulting in narrowing the field of view, and therefore had to move their heads to see the space of the room. This follows the theoretical expectation for the proposed concept. Thus, the proposed device may help nystagmus subjects fixate the image on the center of the retina and thus enable improved visual acuity. The device may be used in young children suffering from nystagmus to prevent amblyopia.

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Novel technologies are constantly under development for vision restoration in blind patients. Many of these emerging technologies are based on the projection of high intensity light patterns at specific wavelengths, raising the need for the development of specialized projection systems. Here we present and characterize a novel projection system that meets the requirements for artificial retinal stimulation in rats and enables the recording of cortical responses. The system is based on a customized miniature Digital Mirror Device (DMD) for pattern projection, in both visible (525 nm) and NIR (915 nm) wavelengths, and a lens periscope for relaying the pattern directly onto the animal's retina. Thorough system characterization and the investigation of the effect of various parameters on obtained image quality were performed using ZEMAX. Simulation results revealed that images with an MTF higher than 0.8 were obtained with little effect of the vertex distance. Increased image quality was obtained at an optimal pupil diameter and smaller field of view. Visual cortex activity data was recorded simultaneously with pattern projection, further highlighting the importance of the system for prosthetic vision studies. This novel head mounted projection system may prove to be a vital tool in studying natural and artificial vision in behaving animals.

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This paper deals with the development of a computed optical tomography system designed and built to inspect glass lattices to locate various impurities inside the bulk. We focus on the investigation of the potential benefit in the usage of extended depth of focus optics for that application. The quality of 3D reconstruction for the application of glass lattice defect identification is tested numerically and experimentally against the corresponding result obtained with conventional optics.

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OBJECTIVE: To test the incidence and sonographic parameters of pyelonephritis during pregnancy, and to examine risk factors and pregnancy outcomes of women with acute antepartum pyelonephritis. STUDY DESIGN: A retrospective population-based study comparing all singleton pregnancies of patients with and without acute antepartum pyelonephritis was performed. Patients lacking prenatal care as well as multiple gestations were excluded from the study. Multiple logistic regression models were used to control for confounders. RESULTS: Out of 219,612 singleton deliveries in 1988-2010, 165 women (0.07%) suffered from acute antepartum pyelonephritis. Abnormal sonographic findings were found in 85.7% of the patients with pyelonephritis. Pyelonephritis was significantly associated with nulliparity (46.1% vs. 24.4%, p<0.001), younger maternal age (26.3 ± 6.0 vs. 28.6 ± 5.8 years, p<0.001), intrauterine growth restriction (IUGR) (6.7% vs. 2.1%, p<0.001), placental abruption (3.6% vs. 0.7%, p<0.001), low 1 min Apgar scores (10.3% vs. 6.0%, p<0.05), urinary tract infection (UTI) (4.2% vs. 0.4%, p<0.001) and preterm delivery (less than 37 weeks gestation; 20.0% vs. 7.8%; p<0.001). Using a multivariable analysis, independent risk factors for acute antepartum pyelonephritis were nulliparity (OR 2.0; 95% C.I 1.4-2.9; p<0.001), UTI (OR 10.3; 95% C.I 4.8-22.1; p<0.001) and younger maternal age (OR 0.96; 95% C.I 0.93-0.99; p=0.009). Using another multivariable analysis, with preterm delivery as the outcome variable, acute antepartum pyelonephritis was found as an independent risk factor for preterm delivery (OR 2.6; 95% C.I 1.7-3.9; p<0.001). CONCLUSION: Acute antepartum pyelonephritis is associated with adverse perinatal outcomes and specifically is an independent risk factor for preterm delivery.

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Passive ophthalmic optic devices correct refractive defects of the eye but are not designed to employ neural adaptation processes. An extended depth of focus technology is implemented on conventional refractive devices, such as spectacles and contact lenses, and its testing is described. This technology is capable of simultaneously correcting all refractive errors, such as myopia, hyperopia, presbyopia, regular/irregular astigmatism, as well as their combinations. This is achieved by exploiting the capacity of the visual system for adaptation to contrast as well as its capability of creating a coherent continuous visual field out of discrete lines of sight.

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PURPOSE: To measure the optical performance of an extended depth of focus (EDOF) intraocular lens (IOL), which provides an imaging solution for near, intermediate, and distance ranges, and to compare its optical performance to available bifocal IOLs with various extents of decentration and astigmatism aberrations. METHODS: A special profile that performs interference principle-based focal extension is engraved on the top of a monofocal rigid IOL. An optical bench based on the L&B eye model was used to test the performance in comparison with the bifocal AcrySof ReSTOR SA60D3 lens (Alcon Laboratories Inc). RESULTS: The imaging performances at near, intermediate, and distance ranges were mapped. Different decentration parameters and amount of astigmatism aberration were tested. In numerical simulations and the experimental bench, the EDOF IOL was demonstrated to have good visual acuity in near, intermediate, and distance ranges as well as reduced sensitivity to decentration of up to 0.75 mm and the capability of correcting astigmatism aberrations of up to 1.00 diopter. CONCLUSIONS: Extended depth of focus technology is capable of providing clear and focused vision at near, intermediate, and distance ranges. Its high quality imaging is obtained under large decentration conditions and residual astigmatism. This capability broadens the potential use of the technology beyond its application as a simultaneous multifocal lens.

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We overview the benefits that extended depth of focus technology may provide for three-dimensional imaging and profilometry. The approaches for which the extended depth of focus benefits are being examined include stereoscopy, light coherence, pattern projection, scanning line, speckles projection, and projection of axially varied shapes.

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The purpose of this Letter is to design, develop, fabricate, and test in clinical trials a new (to our knowledge) type of contact lenses that provides simultaneous near and distance focused vision for presbyopic subjects, including those with up to 2.00 diopters (D) of regular/irregular astigmatism, as an alternative to multifocal contact lenses. The purpose is obtained by generating an optical pattern on the front surface of contact lenses, capable of extending the depth of focus of lenses by 3.00 D with high visual contrast. The pattern was fabricated on top of contact lenses and tested by the use of an eye simulation as well as in clinical trials. Use of the extended depth of focus contact lens enabled patients to achieve good visual acuity and contrast sensitivity for both distance and near vision without compromising the energy distribution or the visual fields.

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