Gelatin methacryloyl (GelMA) is one of the most widely used photo-crosslinkable biopolymers in tissue engineering. In in presence of an appropriate photoinitiator, the light activation triggers the crosslinking process, which provides shape fidelity and stability at physiological temperature. Although ultraviolet (UV) has been extensively explored for photo-crosslinking, its application has been linked to numerous biosafety concerns, originated from UV phototoxicity. Eosin Y, in combination with TEOA and VC, is a biosafe photoinitiation system that can be activated via visible light instead of UV and bypasses those biosafety concerns; however, the crosslinking system needs fine-tuning and optimization. In order to systematically optimize the crosslinking conditions, we herein independently varied the concentrations of Eosin Y [(EY)], triethanolamine (TEOA), vinyl caprolactam (VC), GelMA precursor, and crosslinking times and assessed the effect of those parameters on the properties the hydrogel. Our data showed that except EY, which exhibited an optimal concentration (~ 0.05 mM), increasing [TEOA], [VA], [GelMA], or crosslinking time improved mechanical (tensile strength/modulus and compressive modulus), adhesion (lap shear strength), swelling, biodegradation properties of the hydrogel. However, increasing the concentrations of crosslinking reagents ([TEOA], [VA], [GelMA]) reduced cell viability in 3-dimensional (3D) cell culture. This study enabled us to optimize the crosslinking conditions to improve the properties of the GelMA hydrogel and to generate a library of hydrogels with defined properties essential for different biomedical applications.

Purpose: Develop equations to convert Cirrus central subfield thickness (CST) to Spectralis CST equivalents and vice versa in eyes with diabetic macular edema (DME). Methods: The DRCR Retina Network Protocol O data were split randomly to train (70% sample) and validate (30% sample) conversion equations. Data from an independent study (CADME) also validated the equations. Bland-Altman 95% limits of agreement between predicted and observed values evaluated the equations. Results: Protocol O included 374 CST scan pairs from 187 eyes (107 participants). The CADME study included 150 scan pairs of 37 eyes (37 participants). Proposed conversion equations are Spectralis = 40.78 + 0.95 × Cirrus and Cirrus = 1.82 + 0.94 × Spectralis regardless of age, sex, or CST. Predicted values were within 10% of observed values in 101 (90%) of Spectralis and 99 (88%) of Cirrus scans in the validation data; and in 136 (91%) of the Spectralis and 148 (99%) of the Cirrus scans in the CADME data. Adjusting for within-eye correlations, 95% of conversions are estimated to be within 17% (95% confidence interval, 14%-21%) of CST on Spectralis and within 22% (95% confidence interval, 18%-28%) of CST on Cirrus. Conclusions: Conversion equations developed in this study allow the harmonization of CST measurements for eyes with DME using a mix of current Cirrus and Spectralis device images. Translational Relevance: The CSTs measured on Cirrus and Spectralis devices are not directly comparable owing to outer boundary segmentation differences. Converting CST values across spectral domain optical coherence tomography instruments should benefit both clinical research and standard care efforts.

BACKGROUND: To review the literature and provide a summary of COVID-19-related neurologic and neuro-ophthalmic complications. METHODS: The currently available literature was reviewed on PubMed and Google Scholar using the following keywords for searches: CNS, Neuro-Ophthalmology, COVID-19, SARS-CoV-2, coronavirus, optic neuritis, pseudotumor cerebri, Acute Disseminated Encephalomyelitis, posterior reversible encephalopathy syndrome (PRES), meningitis, encephalitis, acute necrotizing hemorrhagic encephalopathy, and Guillain-Barré and Miller Fisher syndromes. RESULTS: Neuroradiologic findings of neurologic and neuro-ophthalmologic complications in relationship to COVID-19 infection were reviewed. Afferent visual pathway-related disorders with relevant imaging manifestations included fundus nodules on MRI, papilledema and pseudotumor cerebri syndrome, optic neuritis, Acute Disseminated Encephalomyelitis, vascular injury with thromboembolism and infarct, leukoencephalopathy, gray matter hypoxic injury, hemorrhage, infectious meningitis/encephalitis, acute necrotizing hemorrhagic encephalopathy, and PRES. Efferent visual pathway-related complications with relevant imaging manifestations were also reviewed, including orbital abnormalities, cranial neuropathy, Guillain-Barré and Miller Fisher syndromes, and nystagmus and other eye movement abnormalities related to rhombencephalitis. CONCLUSION: COVID-19 can cause central and peripheral nervous system disease, including along both the afferent and efferent components of visual axis. Manifestations of disease and long-term sequela continue to be studied and described. Familiarity with the wide variety of neurologic, ophthalmic, and neuroradiologic presentations can promote prompt and appropriate treatment and continue building a framework to understand the underlying mechanism of disease.

Purpose: Successful repair of the orbital skeleton restores function and cosmesis by normalizing globe position and allowing full motility of the extraocular muscles. Routine repairs are successful with standard implants. However, defects that are irregular or cause volume deficiency can be challenging to repair. The development of patient specific implants (PSI) offers an additional tool in complex cases. Herein, we report our experience using PSI for orbital reconstruction. Methods: An IRB-approved review was conducted of consecutive patients who received PSI from 8/2016-9/2018. Demographic and examination findings were recorded. PSI was designed using high-density porous polyethylene or polyetheretherketone (PEEK) and implanted for repair. The postoperative course was reviewed for outcomes and complications. Results: Eight patients were identified. Two had silent sinus syndrome, 3 were complex facial fracture revisions, and 3 were post-oncologic reconstruction. Seven received porous polyethylene implants, and 1 had a PEEK implant. Mean follow up time was 10.2 months (3.3-28.3). All had an improved functional and aesthetic result. Diplopia and enophthalmos completely resolved in 60% of fracture and silent sinus patients. All fracture and silent sinus patients were orthotropic without diplopia in primary gaze at last follow up. Tumor patients had improvement in symmetry and functionality. There were no complications. Conclusion and importance: Complex orbital skeleton derangements can be difficult to repair and standard implants may incompletely resolve the anatomic problem. In challenging cases, PSI may better achieve an aesthetically and anatomically successful outcome and improve functionality.

PURPOSE: To study the epidemiology of inpatient open globe injuries (OGI) in the United States (US). METHODS: This was a retrospective cohort study of patients with a primary diagnosis of OGI in the National Inpatient Sample (NIS) from 2009 to 2015. Sociodemographic characteristics, including age, gender, race, ethnicity, insurance, and income were stratified for comparison. Annual prevalence rates were calculated using 2010 US Census data. Statistical analysis included Chi-square tests, ANCOVA, and Tukey tests. RESULTS: A total of 6,821 US inpatient hospital discharge records met inclusion/exclusion criteria. The estimated national prevalence of OGI during the 5-year period from 2009 to 2015 was 34,061 (95% confidence interval [CI] 31,445-36,677). The overall annual prevalence rate was 1.58 per 100,000 per year (CI 1.56-1.59). Overall, average annual prevalence rates were highest among patients 85 years or older (7.72, CI 6.95-8.49), on Medicare (3.92, CI 3.84-4.00), males (2.28, CI 2.25-2.30), African Americans (2.38, CI 2.32-2.44), and Native Americans (1.80, CI 1.62-2.00). OGI rates were lowest among Whites (1.21, CI 1.19-1.22), females (0.89, CI 0.87-0.91), those with private insurance (0.84, CI 0.82-0.86), and Asians (0.69, CI 0.64-0.74). Being in the lowest income quartile was a risk factor for OGI (p < .05). CONCLUSIONS: Inpatient OGIs disproportionately affected those over 85, young males, elderly females, patients of African-American descent, on Medicare, and in the lowest income quartile. Additionally, children and young children had lower rates of OGI compared to adolescents. Further studies should delineate causes for socioeconomic differences in OGI rates to guide future public health measures.

The retina is a light-sensing ocular tissue that sends information to the brain to enable vision. The blood-retinal barrier (BRB) contributes to maintaining homeostasis in the retinal microenvironment by selectively regulating flux of molecules between systemic circulation and the retina. Maintaining such physiological balance is fundamental to visual function by facilitating the delivery of nutrients and oxygen and for protection from blood-borne toxins. The inner BRB (iBRB), composed mostly of inner retinal vasculature, controls substance exchange mainly via transportation processes between (paracellular) and through (transcellular) the retinal microvascular endothelium. Disruption of iBRB, characterized by retinal edema, is observed in many eye diseases and disturbs the physiological quiescence in the retina's extracellular space, resulting in vision loss. Consequently, understanding the mechanisms of iBRB formation, maintenance, and breakdown is pivotal to discovering potential targets to restore function to compromised physiological barriers. These unraveled targets can also inform potential drug delivery strategies across the BRB and the blood-brain barrier into retinas and brain tissues, respectively. This review summarizes mechanistic insights into the development and maintenance of iBRB in health and disease, with a specific focus on the Wnt signaling pathway and its regulatory role in both paracellular and transcellular transport across the retinal vascular endothelium.

Ocular involvement is a rare manifestation of tuberculosis. Four key issues historically faced by clinicians when diagnosing and treating ocular tuberculosis - diagnostic uncertainty, naturally heterogeneous presentations, limitations of existing laboratory diagnostic tools, and non-uniform treatment guidelines - continue to test today's physicians. Unparalleled scientific and clinical developments over the past century have greatly expanded the knowledge surrounding this challenging ophthalmic condition. Experience with large volumes of cases at tuberculosis-endemic centres has led to recent growth in knowledge and physician experience, perhaps more so in developing countries. Looking forward, the role of diverse new technologies, including artificial intelligence and proteomics, will advance ocular tuberculosis research. Efforts have been made to address the lack of standardized nomenclature, diagnostic uncertainty, and unvalidated, geographically variable treatment guidelines.

BACKGROUND: Eyelid warming is an important treatment for meibomian gland dysfunction (MGD). Specialized chambered devices, using warm moist air have been developed. PURPOSE: To critically evaluate the literature on the safety and efficacy of chambered warm moist air devices in MGD treatment and pinpoint areas of future research. METHODS: PubMed and Embase were searched on 06 June 2021. The search term was '(warm OR heat OR steam OR goggle OR spectacle OR moist air) AND (meibomian OR MGD OR blepharitis OR eyelid OR dry eye OR DED)'. All relevant articles with available English full text were included. RESULTS: Eighteen articles assessing the application of chambered warm moist air eyelid warming devices were identified. In single-application studies, steam-based eyelid warming increased the eyelid temperature and improved symptoms, lipid layer thickness, and tear film breakup time (TBUT). In treatment studies, the steam-based devices improved TBUT and symptom scores. However, in the only randomized controlled trial (RCT) comparing chambered steam-based heat to hot towel treatment, there was no difference between groups for the primary outcome measure; the proportion of subjects noting symptom improvement after 4 weeks. CONCLUSION: Currently available chambered warm moist air eyelid warming devices are safe and effective at raising eyelid temperature to therapeutic levels and improving signs and symptoms of dry eye. However, it is not clear if they provide a greater benefit than other eyelid warming therapies. Further well-conducted RCTs comparing moist and dry heat devices should be conducted on patients across the range of DED severities and subtype spectrum.

PURPOSE: To estimate the incidence of corneal endothelial transplantation and identify risk factors among patients with non-infectious ocular inflammation. DESIGN: Retrospective cohort study. METHODS: Adult patients attending United States tertiary uveitis care facilities diagnosed with non-infectious ocular inflammation were identified from the Systemic Immunosuppressive Therapy for Eye Diseases Cohort Study. Time-to-event analysis was used to estimate the incidence of corneal endothelial transplantation (CET), including penetrating keratoplasty, Descemet stripping endothelial keratoplasty, or Descemet Membrane Endothelial Keratoplasty procedures. The incidence of CET was calculated; potential risk factors for CET were also evaluated using Cox regression, accounting for correlation between eyes of the same patient. RESULTS: Overall, 14,264 eyes met eligibility criteria for this analysis with a median follow-up 1.8 eye-years. The Kaplan-Meier estimated incidence of CET within 10 years was 1.10% (95% CI, 0.68%-1.53%). Risk factors for CET included age >60 years vs. <40 years (aHR 16.5; 95% CI,4.70-57.9), anterior uveitis and scleritis vs. other types (aHR 2.97; 95% CI, 1.46-6.05 and aHR 4.14; 95% CI,1.28-13.4, respectively), topical corticosteroid treatment (aHR 2.84; 95% CI, 1.32-6.13), cataract surgery (aHR 4.44; 95% CI, 1.73-11.4), tube shunt surgery (aHR 11.9; 95% CI, 5.30-26.8), band keratopathy (aHR 5.12; 95% CI, 2.34-11.2), and hypotony (aHR 7.38; 95% CI, 3.14-17.4). Duration of uveitis, trabeculectomy, PAS, and ocular hypertension had no significant association after multivariate adjustment. CONCLUSIONS: In patients with ocular inflammation, CET occurred infrequently. Tube shunt surgery, hypotony, band keratopathy, cataract surgery, and anterior segment inflammation were associated with increased risk of undergoing corneal endothelial transplantation; these factors likely are associated with endothelial cell damage.

Meibomian gland dysfunction (MGD) is the most common cause of dry eye disease (DED). In this study, we aimed to compare the effects of eyelid warming treatment using either TheraPearl Eye Mask (Bausch & Lomb Inc., New York, USA) or Blephasteam (Spectrum Thea Pharmaceuticals LTD, Macclesfield, UK) in a Norwegian population with mild to moderate MGD-related DED. An open label, randomized comparative trial with seventy patients (49 females, 21 males; mean age 53.6 years). Patients were randomly assigned to treatment with Blephasteam (n = 37) or TheraPearl (n = 33). All received a hyaluronic acid based artificial tear substitute (Hylo-Comod, Ursapharm, Saarbrücken, Germany). Patients were examined at baseline, and at three and six months initiation of treatment. Treatment efficacy was primarily evaluated by fluorescein breakup time (FBUT) and Ocular Surface Disease Index (OSDI) scores. Other outcome measures included ocular surface staining (OSS), Schirmer's test, and meibomian quality and expressibility. Baseline parameter values did not differ between the groups. After six months of treatment, Blephasteam improved FBUT by 3.9 s (p < 0.01) and OSDI by 13.7 (p < 0.01), TheraPearl improved FBUT by 2.6 s (p < 0.01) and OSDI by 12.6 (p < 0.01). No difference between treatments was detected at 6 months (p = 0.11 for FBUT and p = 0.71 for OSDI), nor were there differences in the other tested parameters between the treatment groups. Blephasteam and TheraPearl are equally effective in treating mild to moderate MGD in a Norwegian population after 6-months of treatment.Clinicaltrials.gov ID: NCT03318874; Protocol ID: 2014/1983; First registration: 24/10/2017.