COVID-19 and Ophthalmology: A New Chapter in an Old Story

Editorial, No Abstrac

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

Besifloxacin ophthalmic suspension, 0.6%: a novel topical fluoroquinolone for bacterial conjunctivitis

Acute bacterial conjunctivitis, the most common cause of conjunctivitis, is responsible for approximately 1% of all primary-care consultations. Of the topical ophthalmic antibiotics used to treat acute bacterial conjunctivitis, fluoroquinolones are especially useful because they possess a broad antibacterial spectrum, are bactericidal in action, are generally well tolerated, and have been less prone to development of bacterial resistance. Besifloxacin, the latest advanced fluoroquinolone approved for treating bacterial conjunctivitis, is the first fluoroquinolone developed specifically for topical ophthalmic use. It has a C-8 chlorine substituent and is known as a chloro-fluoroquinolone. Besifloxacin possesses relatively balanced dual-targeting activity against bacterial topoisomerase IV and DNA gyrase (topoisomerse II), two essential enzymes involved in bacterial DNA replication, leading to increased potency and decreased likelihood of bacterial resistance developing to besifloxacin. Microbiological data suggest a relatively high potency and rapid bactericidal activity for besifloxacin against common ocular pathogens, including bacteria resistant to other fluoroquinolones, especially resistant staphylococcal species. Randomized, double-masked, controlled clinical studies demonstrated the clinical efficacy of besifloxacin ophthalmic suspension 0.6% administered three-times daily for 5 days to be superior to the vehicle alone and similar to moxifloxacin ophthalmic solution 0.5% for bacterial conjunctivitis. In addition, besifloxacin ophthalmic suspension 0.6% administered two-times daily for 3 days was clinically more effective than the vehicle alone for bacterial conjunctivitis. Besifloxacin has also been shown in preclinical animal studies to be potentially effective for the "off-label" treatment of infections following ocular surgery, prophylaxis of endophthalmitis, and the treatment of bacterial keratitis. Taken together, clinical and preclinical animal studies indicate that besifloxacin is an important new option for the treatment of ocular infections

Allergic conjunctivitis: an update on diagnosis and management

The focus of this review is to provide a logical paradigm for the diagnosis and treatment of ocular allergies, with a focus on seasonal allergic conjunctivitis (SAC) and perennial allergic conjunctivitis (PAC). Several classes of topical medications are currently available for the management of ocular allergies, including: lubricating agents, vasoconstrictors, antihistamines, mast cell stabilizers, and topical corticosteroids. SAC and PAC make up the vast majority of ocular allergy cases. A proactive approach to these diseases, anticipating the regional spring and fall allergen spikes, is needed for optimally managing these disorders. A multifaceted treatment regimen comprising patient education, lifestyle modification, and topical medications (such as antihistamines and/or mast cell stabilizers and corticosteroids) may be required in order to manage ocular allergies effectively. The appropriate treatment paradigm is based on the severity of the patients' signs and symptoms. For moderate-to-severe cases, especially chronic vernal keratoconjunctivitis, atopic keratoconjunctivitis, and giant papillary conjunctivitis, comanagement with an ophthalmologist is recommended

Ophthalmology

The concept of modifying the shape of the cornea to induce changes in the refractive state of the eye is not new, but recent reports of improved success with newer procedures and technologies have generated increased enthusiasm among ophthalmologists and patients anxious to eliminate the need for glasses or contact lenses. However, amid the new wave of excitement persist concerns among many ophthalmologists about predictable efficacy and consistent safety of some refractive surgical procedures.It has been four decades since development of a surgical approach to correct myopia by creating anterior and posterior radial incisions in the cornea.1 Although initial procedures successfully reduced the amount of myopia, nearly 75% of the eyes developed corneal edema in 10 to 20 years, presumably caused by damage to the corneal endothelium.2 Modifications of the early Japanese technique were followed by a shift to anterior radial incisions only, as popularized by th

Conjunctival tissue pharmacokinetic properties of topical azithromycin 1% and moxifloxacin 0.5% ophthalmic solutions: A single-dose, randomized, open-label, active-controlled trial in healthy adult volunteers

Background: Effective ocular tissue concentrations and prolonged residence times of antibacterial agents are important in treating both acute and chronic diseases. Conjunctival biopsy allows the determination of specific tissue concentration data for topical ophthalmic agents. Drug concentration analysis at various time points following instillation allows interpretation of the residence time and a rationale for dosing frequency. Objective: This study compared the pharmacokinetic parameters of 2 currently available topical ocular antibiotics—azithromycin ophthalmic solution 1% and moxifloxacin ophthalmic solution 0.5%—in the conjunctiva of healthy volunteers after a single topical administration. Methods: This single-dose, randomized, open-label, active-controlled clinical trial was conducted at ORA Clinical Research and Development, North Andover, Massachusetts. Subjects were randomly assigned to receive a single dose of azithromycin or moxifloxacin and to undergo biopsy sampling at 30 minutes or 2, 12, or 24 hours after administration. Concentrations of azithromycin and moxifloxacin were determined using liquid chromatography tandem mass spectrometry. Adverse events (AEs) were assessed at all visits using visual acuity measurements, slit-lamp biomicroscopy, and direct questioning. Results: Forty-eight subjects (mean age, 40.0 years; 48% female; 96% white, 2% black, and 2% Asian) underwent conjunctival biopsy. Mean (SD) concentrations of azithromycin in conjunctival tissue (lower limit of quantitation [LLOQ], 1 µg/g for 1-mg biopsy specimen) were 131 (89), 59 (19), 48 (24), and 32 (20) µg/g at 30 minutes and 2, 12, and 24 hours, respectively (median values, 117, 69, 46, and 30 µg/g). Mean concentrations concentrations of moxifloxacin in conjunctival tissue (LLOQ, 0.05 µg/g for 1-mg biopsy sample) were 1.92 (2.03), 3.77 (8.98), 0.02 (0.04), and 0.01 (0.02) µg/g at 30 minutes and 2, 12, and 24 hours, respectively (median values, 1.12, 0.12, <0.05, and <0.05 µg/g). Thirteen subjects (6 in the azithromycin group and 7 in the moxifloxacin group) experienced 20 AEs, 11 of which were considered possibly related to study treatment, and 15 of which were ocular (most commonly conjunctival hemorrhage). Conclusions: In this single-dose study of 2 currently available topical ocular antibiotics in healthy volunteers, therapeutic concentrations were achieved with both agents. Both treatments were well tolerated in the population studied. Clinical Trials Identification Number: NCT00564447