Bioequivalence and the food effect of macitentan/tadalafil 10/20 fixed-dose combination tablets versus the use of single-component tablets in healthy subjects.

The primary aim was to demonstrate bioequivalence between the 10/20 mg fixed-dose combination (FDC) of macitentan/tadalafil in a single tablet and the free combination of both drugs, and to evaluate the food effect on the 10/20 mg FDC in healthy participants. In this single-center, randomized, open-label, 3-way crossover, single-dose Phase 1 study in healthy adult participants, macitentan/tadalafil was administered as a 10/20 mg FDC formulation and compared with the free combination of macitentan and tadalafil. The food effect on the FDC was also evaluated. Pharmacokinetic sampling (216 h) was conducted. The 90% confidence intervals (CIs) for the geometric mean ratios of maximum observed plasma analyte concentration (Cmax) and area under the plasma analyte concentration-time curves (AUCs) for Treatment A (FDC, fasted) versus C (free combination, fasted) were within bioequivalence limits demonstrating that the FDC formulation can be considered bioequivalent to the free combination. The 90% CIs for the geometric mean ratios of Cmax and AUC for Treatment B (FDC, fed) versus A (FDC, fasted) were contained within bioequivalence limits demonstrating that there was no food effect. The administration of the 10/20 mg FDC was generally safe and well tolerated in healthy participants. This study demonstrated bioequivalence between the FDC of macitentan/tadalafil (10/20 mg) in a single tablet and the free combination of both drugs in healthy participants, and that the FDC can be taken without regard to food, similarly to the individual components. The FDC was generally safe and well tolerated.

Cooling Anesthesia for Intravitreal Injection: Results of the Prospective Open-Label, Dose-Ranging COOL-1 Trial.

PURPOSE: To evaluate the safety and efficacy of a novel medical device to provide cooling anesthesia to the eye as local anesthesia for intravitreal injections. STUDY DESIGN: First in human, open-label study of 43 subjects assessed at three different doses: -10°C for 20 seconds (group 1), -15°C for 15 seconds (group 2), and -15°C for 20 seconds (group 3). Main outcome measures were safety and pain of injection using a numeric rating scale (NRS). RESULTS: Cooling anesthesia did not result in any serious ocular adverse events. One grade 1 adverse event was a vasovagal response during cooling administration which resolved immediately after cooling. Mean NRS scores at the time of injection for each group ranged from 2.5 to 4.3 There was a statistically significant difference between pain scores of the 3 groups at injection in aggregate but not in pairwise comparisons (P value = 0.047). There was a statistically significant decrease in pain from injection to 5 minutes post injection in all groups (P value = 0.00008, 0.003, 0.0005 for groups 1, 2, 3, respectively) as well as from 5 minutes to 24-48 hours (P value = 0.00001, 0.018, and 0.0545 for groups 1, 2, 3, respectively). CONCLUSION: The rapid cooling anesthesia device was well tolerated for achieving local anesthesia among patients receiving intravitreal injections with no serious ocular adverse events.

Advances in Retinal Oximetry.

Similar to other organs, the retina relies on tightly regulated perfusion and oxygenation. Previous studies have demonstrated that retinal blood flow is affected in a variety of eye and systemic diseases, including diabetic retinopathy, age-related macular degeneration, and glaucoma. Although measurement of peripheral oxygen saturation has become a standard clinical measurement through the development of pulse oximetry, developing a noninvasive technique to measure retinal oxygen saturation has proven challenging, and retinal oximetry technology currently remains inadequate for reliable clinical use. Here, we review current strategies and approaches, as well as several newer technologies in development, and discuss the future of retinal oximetry.

Research Funding, Income, and Career Satisfaction Among Clinician-Scientists in Ophthalmology in the United States.

PURPOSE: The purpose of this study was to characterize clinician-scientists in ophthalmology and identify factors associated with successful research funding, income, and career satisfaction. DESIGN: Cross-sectional study. METHODS: A survey was conducted of clinician-scientists in ophthalmology at US academic institutions between April 17, 2019, and May 19, 2019. Collected information including 1) demographic data; 2) amount, type, and source of startup funding; first extramural grant; and first R01-equivalent independent grant; 3) starting and current salaries; and 4) Likert-scale measurements of career satisfaction were analyzed using multivariate regression. RESULTS: Ninety-eight clinician-scientists in ophthalmology were surveyed across different ages (mean: 48 ± 11 years), research categories, institutional types, geographic regions, and academic ranks. Median startup funding ranged from $50-99k, and median starting salaries ranged from $150-199k. A majority of investigators (67%) received their first extramural award from the National Eye Institute, mainly through K-award mechanisms (82%). The median time to receiving their first independent grant was 8 years, mainly through an R01 award (70%). Greater institutional startup support (P = .027) and earlier extramural grant success (P = .022) were associated with earlier independent funding. Male investigators (P = .001) and MD degreed participants (P = .008) were associated with higher current salaries but not starting salaries. Overall career satisfaction increased with career duration (P = .011) but not with earlier independent funding (P = .746) or higher income (P = .300). CONCLUSIONS: Success in research funding by clinician-scientists in ophthalmology may be linked to institutional support and earlier acquisition of extramural grants but does not impact academic salaries. Nevertheless, career satisfaction among clinician-scientists improves with time, which is not necessarily influenced by research or financial success.

SGLT2 Inhibitor-Induced Low-Grade Ketonemia Ameliorates Retinal Hypoxia in Diabetic Retinopathy-A Novel Hypothesis.

Diabetic retinopathy (DR) is a well-recognized microvascular complication of diabetes. Growing evidence suggests that, in addition to retinal vascular damage, there is significant damage to retinal neural tissue in DR. Studies reveal neuronal damage before clinically evident vascular lesions and DR is now classified as a neurovascular complication. Hyperglycemia causes retinal damage through complex metabolic pathways leading to oxidative stress, inflammation, vascular damage, capillary ischemia, and retinal tissue hypoxia. Retinal hypoxia is further worsened by high oxygen consumption in the rods. Persistent hypoxia results in increases in vascular endothelial growth factor (VEGF) and other pro-angiogenic factors leading to proliferative DR/macular edema and progressive visual impairment. Optimal glucose control has favorable effects in DR. Other treatments for DR include laser photocoagulation, which improves retinal oxygenation by destroying the high oxygen consuming rods and their replacement by low oxygen consuming glial tissue. Hypoxia is a potent stimulator of VEGF, and intravitreal anti-VEGF antibodies are effective in regressing macular edema and in some studies, retinal neovascularization. In this review, we highlight the complex pathophysiology of DR with a focus on retinal oxygen/fuel consumption and hypoxic damage to retinal neurons. We discuss potential mechanisms through which sodium-glucose cotransporter 2 (SGLT2) inhibitors improve retinal hypoxia-through ketone bodies, which are energetically as efficient as glucose and yield more ATP per molecule of oxygen consumed than fat, with less oxidative stress. Retinal benefits would occur through improved fuel energetics, less hypoxia and through the anti-inflammatory/oxidative stress effects of ketone bodies. Well-designed studies are needed to explore this hypothesis.

BILATERAL ENTEROCOCCUS FAECALIS ENDOPHTHALMITIS WITH MULTIPLE RECURRENCES.

PURPOSE: To describe the first case report of a bilateral recurrent Enterococcus faecalis endophthalmitis postcataract surgery. METHODS: Case report with a description of the timeline, diagnosis, and management of a patient with bilateral recurrent E. faecalis endophthalmitis. RESULTS: An 89-year-old man presented 6 weeks' postcataract surgery with pain, tearing, and blurred vision in the left eye. B-scan ultrasonography revealed vitritis and cultures postvitrectomy grew E. faecalis. There was gradual improvement in vision postintravitreal vancomycin administration. Four years later, the patient experienced another episode of E. faecalis endophthalmitis in the right eye postcataract extraction, followed by several additional episodes in both eyes posttreatment. CONCLUSION: Enterococcus faecalis is a rare but highly virulent cause of endophthalmitis that may remain sequestered in the capsular bag, despite aggressive treatment. Even after recurrent episodes, early vitrectomy and aggressive antibiotic therapy may prove to be effective in preventing vision loss.

Implementing the new normal in ophthalmology care beyond COVID-19.

The COVID-19 pandemic has altered the clinical landscape immeasurably. The need to physical distance requires rethinking how we deliver ophthalmic care. Within healthcare, we will need to focus our resources on the five T's: Utilising technology, multidisciplinary clinical teams with wide professional talents need to work efficiently to reduce patient contact time. With regular testing, this will allow us to reduce the risk further. We also must acknowledge the explosion of different modalities to train our future ophthalmologists and the global challenges and advantages that these bring. Finally, we must not forget the psychological impact that this pandemic will have on ophthalmologists and ancillary staff, and need to have robust mechanisms for support.

Assessment of Respiratory Droplet Transmission During the Ophthalmic Slit-Lamp Exam: A Particle Tracking Analysis.

PURPOSE: The global COVID-19 pandemic has resulted in a renewed focus on the importance of personal protective equipment (PPE) and other interventions to decrease spread of infectious diseases. Although several ophthalmology organizations have released guidance on appropriate PPE for surgical procedures and ophthalmology clinics, there is limited experimental evidence that demonstrates the efficacy of various interventions that have been suggested. In this study, we evaluated high-risk aspects of the slit-lamp exam and the effect of various PPE interventions, specifically the use of a surgical mask and a slit-lamp shield. DESIGN: Experimental simulation study. METHODS: This was a single-center study in a patient simulation population. This study examined the presence of particles in the air near or on a slit-lamp, a simulated slit-lamp examiner, or a simulated patient using a fluorescent surrogate of respiratory droplets. RESULTS: Simulated coughing without a mask or slit-lamp shield resulted in widespread dispersion of fluorescent droplets during the model slit-lamp examination. Coughing with a mask resulted in the most significant decrease in droplets; however, particles still escaped from the top of the mask. Coughing with the slit-lamp shield alone blocked most of forward particle dispersion; however, significant distributions of respiratory droplets were found on the slit-lamp joystick and table. Coughing with both a mask and slit-lamp shield resulted in the least dispersion to the simulated examiner and the simulated patient. Scanning electron microscopy demonstrated particle sizes of 3-100 µm. CONCLUSIONS: Masking had the greatest effect in limiting spread of respiratory droplets, whereas slit-lamp shields and gloves also contributed to limiting exposure to droplets from SARS-CoV-2 during slit-lamp examination.

Elovl2 Is Required for Robust Visual Function in Zebrafish.

Omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) play critical roles in membrane stability and cell signaling within the retina. ELOVL2 (Elongation of Very Long Chain Fatty Acids-Like 2), an elongase involved in the synthesis of long chain polyunsaturated fatty acids (LC-PUFAs), has recently been implicated in regulating aging in the mammalian retina. In this work, we characterize the expression and function of elovl2 in the retina development in embryonic zebrafish. Whole mount in situ hybridization shows elovl2 is expressed in the Muller glia in embryonic and adult zebrafish. Lipidomics analysis of elovl2 crispants whole embryos at day 2 and eyes at day 7 demonstrated significant changes in lipids composition, especially on the level of lipids containing docosahexaenoic acid (DHA). Histological analysis of zebrafish lacking elovl2 revealed increased retinal thickness compared to controls at day 7 without gross disruptions of the retinal architecture. Finally, elovl2 crispants showed differences in the visual motor reflex light off (VMR-OFF) at day 7 compared to controls. In sum, inactivation of elovl2 in zebrafish embryos caused changes in lipid composition and in visual behavior, further confirming the important role of LC-PUFAs in healthy vision.

ELOVL2: Not just a biomarker of aging.

DNA methylation of the ELOVL2 (Elongation Of Very Long Chain Fatty Acids-Like 2) promoter is one of the most robust molecular biomarkers for chronological age, but whether ELOVL2 plays a functional role in aging has not been explored. ELOVL2 encodes a transmembrane protein involved in the synthesis of very long polyunsaturated fatty acids (VLC-PUFAs). These fatty acids play important roles in retinal biology and photoreceptor renewal, key processes implicated in age-related eye diseases such as age-related macular degeneration (AMD). Here, we summarize our work deciphering the role of ELOVL2 in the eye emphasizing the potential functional role of age-related DNA methylation in the pathophysiology of AMD.

Assessing the Physiological Relevance of Cough Simulators for Respiratory Droplet Dispersion.

Various breathing and cough simulators have been used to model respiratory droplet dispersion and viral droplets, in particular for SARS-CoV-2 modeling. However, limited data are available comparing these cough simulations to physiological breathing and coughing. In this study, three different cough simulators (Teleflex Mucosal Atomization Device Nasal (MAD Nasal), a spray gun, and GloGermTM MIST) that have been used in the literature were studied to assess their physiologic relevance. Droplet size, velocity, dispersion, and force generated by the simulators were measured. Droplet size was measured with scanning electron microscopy (SEM). Slow-motion videography was used to 3D reconstruct and measure the velocity of each simulated cough. A force-sensitive resistor was used to measure the force of each simulated cough. The average size of droplets from each cough simulator was 176 to 220 µm. MAD Nasal, the spray gun, and GloGermTM MIST traveled 0.38 m, 0.89 m, and 1.62 m respectively. The average velocities for the MAD Nasal, spray gun, and GloGermTM MIST were 1.57 m/s, 2.60 m/s, and 9.27 m/s respectively, and all yielded a force of <0.5 Newtons. GloGermTM MIST and the spray gun most closely resemble physiological coughs and breathing respectively. In conclusion, none of the simulators tested accurately modeled all physiologic characteristics (droplet size, 3-D dispersion velocity, and force) of a cough, while there were various strengths and weaknesses of each method. One should take this into account when performing simulations with these devices.

Quality of Life Assessment of Severely Visually Impaired Individuals Using Aira Assistive Technology System.

Purpose: To assess patient-reported quality of life outcome improvements in severely visually impaired (SVI) individuals using the Aira system over a 1-year follow-up period. Methods: Aira is an on-demand assistive technology designed for SVI. Aira subscribers were recruited and administered the validated 28-item Impact of Vision Impairment-Very Low Vision Questionnaire by phone before starting Aira with follow-ups at 3 months and 1 year. Total score and validated subset scores of activities of daily living, mobility, and safety (ADLMS) and emotional well-being (EWB) were assessed. Pearson correlation analyses and paired t-tests were used to examine the data. Results: Fifty participants (mean, age, 52.5 years; 25 males, 25 females) were recruited with a mean of 401 ± 66.3 days to follow-up. The initial total score (mean, 53.1 ± 18.9) significantly improved at 1 year (mean, 63.1 ± 16.2; P = 0.0002). The initial ADLMS score (mean, 30.7 ± 11.3) significantly improved at 1 year (mean, 37.2 ± 10.7; P = 0.001). The initial EWB score (mean, 22.5 ± 8.5) significantly improved at 1 year (mean, 25.9 ± 8.0; P = 0.0001). There was no significant difference between the 3-month and 1-year total (P = 0.972), ADLMS (P = 0.897), and EWB scores (P = 0.700). There was a significant correlation between minutes used and improvement in total (r = 0.371; P = 0.009), ADLMS (r = 0.302; P = 0.035), and EWB (r = 0.439; P = 0.002) scores. Conclusions: Aira use significantly improves Impact of Vision Impairment-Very Low Vision total, ADLMS, and EWB scores for SVI individuals at 3 months. This improvement is sustained at the 1-year follow-up and correlated with total minutes used. Translational Relevance: Aira technology may provide sustained improvement in quality of life for SVI, and further study to evaluate the usefulness of this technology to assist SVI may be beneficial.

Targeting of the NRL Pathway as a Therapeutic Strategy to Treat Retinitis Pigmentosa.

Retinitis pigmentosa (RP) is an inherited retinal dystrophy (IRD) with a prevalence of 1:4000, characterized by initial rod photoreceptor loss and subsequent cone photoreceptor loss with accompanying nyctalopia, visual field deficits, and visual acuity loss. A diversity of causative mutations have been described with autosomal dominant, autosomal recessive, and X-linked inheritance and sporadic mutations. The diversity of mutations makes gene therapy challenging, highlighting the need for mutation-agnostic treatments. Neural leucine zipper (NRL) and NR2E3 are factors important for rod photoreceptor cell differentiation and homeostasis. Germline mutations in NRL or NR2E3 leads to a loss of rods and an increased number of cones with short wavelength opsin in both rodents and humans. Multiple groups have demonstrated that inhibition of NRL or NR2E3 activity in the mature retina could endow rods with certain properties of cones, which prevents cell death in multiple rodent RP models with diverse mutations. In this review, we summarize the literature on NRL and NR2E3, therapeutic strategies of NRL/NR2E3 modulation in preclinical RP models, as well as future directions of research. In summary, inhibition of the NRL/NR2E3 pathway represents an intriguing mutation agnostic and disease-modifying target for the treatment of RP.

Multiexon deletion alleles of ATF6 linked to achromatopsia.

Achromatopsia (ACHM) is an autosomal recessive disease that results in severe visual loss. Symptoms of ACHM include impaired visual acuity, nystagmus, and photoaversion starting from infancy; furthermore, ACHM is associated with bilateral foveal hypoplasia and absent or severely reduced cone photoreceptor function on electroretinography. Here, we performed genetic sequencing in 3 patients from 2 families with ACHM, identifying and functionally characterizing 2 mutations in the activating transcription factor 6 (ATF6) gene. We identified a homozygous deletion covering exons 8-14 of the ATF6 gene from 2 siblings from the same family. In another patient from a different family, we identified a heterozygous deletion covering exons 2 and 3 of the ATF6 gene found in trans with a previously identified ATF6 c.970C>T (p.Arg324Cys) ACHM disease allele. Recombinant ATF6 proteins bearing these exon deletions showed markedly impaired transcriptional activity by qPCR and RNA-Seq analysis compared with WT-ATF6. Finally, RNAscope revealed that ATF6 and the related ATF6B transcripts were expressed in cones as well as in all retinal layers in normal human retina. Overall, our data identify loss-of-function ATF6 disease alleles that cause human foveal disease.

Anesthesia for Intravitreal Injection: A Systematic Review.

BACKGROUND: The intravitreal injection has become one of the most commonly performed procedures in ophthalmology; however, there is no standardized approach to anesthesia during the procedure. The goal of this systematic review is to review approaches to anesthesia for intravitreal injection and look at comparative efficacy between these different anesthetics. METHODS: A systematic review of literature was performed in the MEDLINE, PubMed, Cochrane Library, and Clinicaltrials.gov databases using the key words "anesthesia", "pain management", and "intravitreal injection". Of the initial 239 search matches, 30 articles were found to be relevant to the topic. 18 studies were excluded as they did not include primary data or did not include the visual analog scale as a primary outcome. The remaining 12 articles were assessed to look at the comparative efficacy of anesthesia and adverse events. RESULTS: The anesthesia techniques reported include topical methods such as anesthetic eyedrops, anesthetic gels, and anesthetic-soaked pledgets as well as subconjunctival injection of anesthetic. Ultimately, no single anesthetic or delivery mechanism was shown to be superior to the others in a statistically significant way and adverse events were largely insignificant. Limitations of these studies include relatively small sizes of the studies, as well as the lack of masking which may introduce bias. CONCLUSION: In the current literature, no type of anesthetic method was found to be superior to another for intravitreal injection. Future studies in this area may lead to new insights into the efficacy of different forms of intravitreal anesthesia.

Genetically Encodable Contrast Agents for Optical Coherence Tomography.

Optical coherence tomography (OCT) has gained wide adoption in biological research and medical imaging due to its exceptional tissue penetration, 3D imaging speed, and rich contrast. However, OCT plays a relatively small role in molecular and cellular imaging due to the lack of suitable biomolecular contrast agents. In particular, while the green fluorescent protein has provided revolutionary capabilities to fluorescence microscopy by connecting it to cellular functions such as gene expression, no equivalent reporter gene is currently available for OCT. Here, we introduce gas vesicles, a class of naturally evolved gas-filled protein nanostructures, as genetically encodable OCT contrast agents. The differential refractive index of their gas compartments relative to surrounding aqueous tissue and their nanoscale motion enables gas vesicles to be detected by static and dynamic OCT. Furthermore, the OCT contrast of gas vesicles can be selectively erased in situ with ultrasound, allowing unambiguous assignment of their location. In addition, gas vesicle clustering modulates their temporal signal, enabling the design of dynamic biosensors. We demonstrate the use of gas vesicles as reporter genes in bacterial colonies and as purified contrast agents in vivo in the mouse retina. Our results expand the utility of OCT to image a wider variety of cellular and molecular processes.

The lipid elongation enzyme ELOVL2 is a molecular regulator of aging in the retina.

Methylation of the regulatory region of the elongation of very-long-chain fatty acids-like 2 (ELOVL2) gene, an enzyme involved in elongation of long-chain polyunsaturated fatty acids, is one of the most robust biomarkers of human age, but the critical question of whether ELOVL2 plays a functional role in molecular aging has not been resolved. Here, we report that Elovl2 regulates age-associated functional and anatomical aging in vivo, focusing on mouse retina, with direct relevance to age-related eye diseases. We show that an age-related decrease in Elovl2 expression is associated with increased DNA methylation of its promoter. Reversal of Elovl2 promoter hypermethylation in vivo through intravitreal injection of 5-Aza-2'-deoxycytidine (5-Aza-dc) leads to increased Elovl2 expression and rescue of age-related decline in visual function. Mice carrying a point mutation C234W that disrupts Elovl2-specific enzymatic activity show electrophysiological characteristics of premature visual decline, as well as early appearance of autofluorescent deposits, well-established markers of aging in the mouse retina. Finally, we find deposits underneath the retinal pigment epithelium in Elovl2 mutant mice, containing components found in human drusen, a pathologic hallmark of age related macular degeneration. These findings indicate that ELOVL2 activity regulates aging in mouse retina, provide a molecular link between polyunsaturated fatty acids elongation and visual function, and suggest novel therapeutic strategies for the treatment of age-related eye diseases.

Rationale for American Society of Retina Specialists Best Practice Recommendations for Conducting Vitreoretinal Surgery during the COVID-19 Era.

PURPOSE: To detail the rationale behind recommendations recently published by the American Society of Retina Specialists (ASRS) outlining best practices for safety of vitreoretinal surgeons and staff while performing vitreoretinal surgery during the coronavirus disease (COVID)-19 pandemic. METHODS: The committee for ASRS Best Practices for Retinal Surgery during the COVID-19 Pandemic reviewed existing evidence and information on SARS-CoV-2 transmission, and risk factors during vitreoretinal surgery. Recommendations were based on best available published data, cumulative clinical experiences, and recommendations and policies from other organizations. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess the strength of recommendations and confidence in the evidence. These serve as interim recommendations which are routinely updated given gaps of knowledge and lack of high-quality data on this evolving subject. RESULTS: Relevant existing literature related to methods of transmission, and ocular manifestations of SARS-CoV-2 are summarized. The data and clinical experiences driving recommendations for pre-operative, intraoperative and post-operative surgical considerations, anesthesia choice, as well as considerations for intravitreal injections are provided. CONCLUSION: Recommendations are provided with the goal of protecting vitreoretinal surgeons and associated personnel from exposure to SARS-CoV-2 during interventional vitreoretinal procedures. This is a rapidly evolving topic with numerous remaining gaps in our current knowledge. As such, recommendations will evolve and the current manuscript is intended to serve as a foundation for continued dialogue on best practices.

Long-Chain Polyunsaturated Fatty Acids and Age-Related Macular Degeneration.

Age-related macular degeneration (AMD) is one of the leading causes of blindness worldwide. Long-chain and very long-chain polyunsaturated fatty acids (LC and VLC-PUFAs) have been linked to AMD pathogenesis through epidemiologic, biochemical, and genetic studies; however, the exact mechanisms of pathogenesis are unknown. Here, we review the scientific and clinical evidence supporting the role of PUFAs in AMD and discuss future directions for elucidating the roles of these fatty acids in AMD pathogenesis.

Emerging Concepts for RNA Therapeutics for Inherited Retinal Disease.

Inherited retinal diseases (IRD) encompass a wide spectrum of hereditary blindness with significant genetic heterogeneity. Therapeutics regulating gene expression on an RNA level have significant promise for treating IRD. In this review, we review the molecular basis of oligonucleotide therapeutics such as ribozymes, RNA interference (RNAi), antisense oligonucleotides (ASO), CRISPRi/a, and their applications to treatments of IRD.