Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network

Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects

Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

Physical and mechanical principles of phacoemulsification and their clinical relevance

A clear understanding of the physical and mechanical principles that govern phacoemulsification can facilitate usage of this technique for effective and efficient cataract removal in a variety of clinical situations. This article addresses separately, concepts pertaining to the three essential components of phacoemulsification, namely, irrigation, aspiration and emulsification. Machine settings are suggested for the various techniques presently in use. Finally, alternative approaches for lens removal that are currently being investigated are briefly discussed

Conjunctival transplantation for corneal surface reconstruction - case reports and review of literature

Corneal persistent epithelial defects (PED) can occur due to various causes. In diffuse ocular surface disease, they often occur secondary to depletion of limbal stem cells. A number of complications occur secondary to PED and successful treatment usually requires conjunctival surgeries for corneal surface reconstruction. We report two cases of chemical injury successfully treated by two such procedures. This report highlights the encouraging results of limbal transplantation and reviews the literature in the management of PED with limbal stem cell loss

Principles and paradigms of pediatric cataract management

Propensity for increased postoperative inflammation and capsular opacification, a refractive state that is constantly in a state of flux due to growth of the eye, difficulty in documenting anatomic and refractive changes due to poor compliance, and a tendency to develop amblyopia, makes management of cataract in the child different from that in the adult. The recent past has unraveled several caveats of pediatric cataract management - the importance of atraumatic surgery and complete removal of lens matter, benefits of in-the-bag intraocular lens(IOL) implantation, role of titrating IOL power to counter refractive changes due to growth of the eye, prudery of continuously following these eyes for early detection of aphakic glaucoma and benefits of some surgical innovations. Although these promise to significantly improve our management of pediatric cataract, their long-term benefits are yet to be determined. We will also have to harness newer techniques, especially in the areas of wound construction and capsule management, and will have to develop effective strategies for the refractive management of infantile aphakia

Laser-assisted cataract surgery and other emerging technologies for cataract removal

As we near the end of this century, refractive cataract surgery has become a reality through concerted contributions from ultrasonic phacoemulsification, foldable intraocular lens (IOL) implantation technology and keratorefractive surgery. As we enter the new millennium, our sights are set on realizing another dream: accommodative IOL surgery. Towards achieving this goal, many advances have been made in both techniques and technology of cataract removal. Lasers in particular have been under investigation for cataract removal for nearly two decades. The technology has now reached a stage where cataract can indeed be removed entirely with laser alone. Neodymium:YAG and erbium:YAG are the laser sources currently utilized by manufacturers of laser phaco systems. Initial clinical experience reported in the literature has served to highlight the capabilities of lasers and the need for further refinement. Despite the excitement associated with the availability of this alluring new technology for cataract removal, it is necessary to develop more effective laser systems and innovative surgical techniques that optimize its capabilities if laser phaco surgery is to be a genuine improvement over current techniques

Utility of IOLMaster 700 Swept-Source Optical Coherence Tomography in Detecting Macular Disease for Preoperative Cataract Surgery Patients

PurposeTo assess the efficacy of IOLMaster 700 (IOLM) biometer swept-source optical coherence tomography (SS-OCT) in detecting macular pathology before cataract surgery and to compare IOLM SS-OCT characteristics of foveal pathology with a widely used spectral-domain OCT (SD-OCT) system.Patients and methodsRetrospective analysis of 1156 consecutive eyes with IOLMaster 700 SS-OCT undergoing cataract surgery from January to June 2017 was performed. Approximately a third of these eyes (327 eyes) also had a SD-OCT scan performed previously. A single reviewer assessed each SS-OCT scan and identified them as "normal" or "abnormal." SS-OCT sensitivity and specificity in identifying foveal pathology was assessed using findings on Spectralis SD-OCT scans as the gold standard.ResultsOf 327 eyes with both IOLM SS-OCT and Spectralis SD-OCT scans, 121 eyes (37.0%) had abnormal SS-OCT scans. Of these 121 eyes, SD-OCT scans confirmed pathology in 104 eyes (86.0%). Of the remaining 206 eyes graded to have normal SS-OCT scans, 84 eyes (40.8%) had normal SD-OCT scans, and 122 eyes (59.2%) had pathologic findings on SD-OCT scans. For each pathologic condition, subtle but definitive differences existed in the appearance of the IOLM SS-OCT and SD-OCT images.ConclusionUsing a normal or abnormal Spectralis SD-OCT scan as confirmation of absence or presence of foveal pathology respectively, we found a high positive predictive value (86.0%) of an abnormal IOLM SS-OCT scan and a high specificity (83.2%) but low sensitivity (46.0%) and negative predictive value (40.8%) of a normal-appearing SS-OCT scan. These results suggest that an abnormal IOLM SS-OCT scan in an eye without known pathology is a strong indicator of an abnormal macula and should prompt further evaluation of the retina to identify pathology prior to cataract surgery. Importantly, IOLM SS-OCT scans do not detect all macular pathology and cannot be used as a screening test for identifying macular pathology