High altitude retinopathy (HAR) is a common ocular disorder that occurs on ascent to high altitude. There are many clinical symptoms, retinal vascular dilatation, retinal edema and hemorrhage are common. These usually do not or slightly affect vision; rarely, severe cases develop serious or permanent vision loss. At present, the research progress of HAR mainly focuses on hemodynamic changes, blood-retinal barrier damage, oxidative stress and inflammatory response. Although the related studies on HAR are limited, it shows that HAR still belongs to hypoxia, and hypobaric hypoxia plays an aggravating role in promoting the development of the disease. Various studies have demonstrated the correlation of HAR with acute mountain sickness (AMS) and high-altitude cerebral edema (HACE), so a deeper understanding of HAR is important. The slow ascent rates and ascent altitude are the key to preventing any altitude sickness. Research on traditional chinese medicine (TCM) and western medicine has been gradually carried out. Further exploration of the pathogenesis and prevention strategies of HAR will provide better guidance for doctors and high-altitude travelers.

High-altitude retinopathy (HAR) is primarily caused by hypobaric hypoxia, leading to hemodynamic changes in the retina and disruption of the blood-retinal barrier (BRB), which results in vasogenic edema. Currently, treatment strategies for this condition are limited. In this study, we investigated the protective effect of nicotinamide mononucleotide (NMN) against high-altitude hypoxia-induced BRB disruption and its potential molecular mechanisms. We established a mouse model of high-altitude BRB injury using a simulated high-altitude environment chamber. Vascular leakage was observed through the Evans Blue dye leakage assay, and retinal Nicotinamide adenine dinucleotide (NAD+) levels were measured using the WST-8 assay. Human umbilical vein endothelial cells (HUVECs) were cultured in a hypoxic chamber, and the permeability of a confluent monolayer to FITC-dextran was monitored. With or without NMN intervention, VE-cadherin expression or phosphorylation at cell junctions was analyzed by Western blot and/or immunofluorescence. Apoptosis levels were assessed via Western blot, TUNEL staining, or flow cytometry, whereas reactive oxygen species (ROS) levels were observed using DCFH-DA, MitoSOX, or DHE probes. DNA damage levels were measured using 8-Oxoguanine immunofluorescence staining, and phosphorylation levels of the Src/Pi3k/Akt signaling pathway were analyzed via Western blot. High-altitude hypoxia led to increased retinal cell apoptosis and significant phosphorylation of VE-cadherin in endothelial cells, which resulted in a marked increase in BRB permeability. Both in vitro and in vivo experiments showed that NMN intervention reduced endothelial cell apoptosis and permeability. Additionally, NMN protected the endothelial barrier by regulating ROS levels in endothelial cells, inhibiting Src phosphorylation, and downregulating the downstream Pi3k/Akt signaling pathway. These findings establish the role of NMN and the ROS-mediated Src/Pi3k/Akt signaling pathway in protecting the endothelial barrier, and identify a potential therapeutic strategy for protecting against hypoxia-related BRB leakage.

Randomized controlled trials (RCTs) are often considered the gold standard and the cornerstone for clinical practice. However, bibliometric studies on worldwide RCTs of ophthalmology published in the 21st century have not been reported in detail yet. This study aims to perform a bibliometric study and visualization analysis of worldwide ophthalmologic RCTs in the 21st century. Global ophthalmologic RCTs from 2000 to 2022 were searched in the Web of Science Core Collection. The number of publications, country/region, institution, author, journal, and research hotspots of RCTs were analyzed using HistCite, VOSviewer, CiteSpace, and Excel software. 2366 institutions and 90 journals from 83 countries/regions participated in the publication of 1769 global ophthalmologic RCTs, with the United States leading in the number of volumes and research field, and the Moorfields Eye Hospital contributing to the most publications. Ophthalmology received the greatest number of publications and co-citations. Jeffrey S. Heier owned the most publications and Jost B. Jonas owned the most co-citations. The knowledge foundations of global ophthalmologic RCTs were mainly retinopathy, glaucoma, dry eye disease (DED), and cataracts, and anti-vascular endothelial growth factor (VEGF) therapy (ranibizumab), topical ocular hypotensive medication, laser trabeculoplasty. Anti-VEGF therapy for age-related macular degeneration (AMD), DME (diabetic macular edema), and DED, the use of new diagnostic tools, and myopia were the hottest research highlights. Anti-VEGF therapy, prompt laser, triamcinolone, and verteporfin photodynamic therapy for AMD, DME, and CNV (choroidal neovascularization), DED, myopia, and open-angle glaucoma were the research hotspots with the longest duration. The future research hotspots might be DED and the prevention and control of myopia. Overall, the number of global ophthalmologic RCTs in the 21st century was keeping growing, there was an imbalance between the regions and institutions, and more efforts are required to raise the quantity, quality, and global impact of high-quality clinical evidence in developing countries/regions.

Purpose: High altitude retinopathy (HAR) is a retinal functional disorder caused by inadequate adaptation after exposure to high altitude. However, the cellular and molecular mechanisms underlying retinal dysfunction remain elusive. Retinal ganglion cell (RGC) injury is the most important pathological basis for most retinal and optic nerve diseases. Studies focusing on RGC injury after high-altitude exposure (HAE) are scanty. Therefore, the present study sought to explore both functional and morphological alterations of RGCs after HAE. Methods: A mouse model of acute hypobaric hypoxia was established by mimicking the conditions of a high altitude of 5000 m. After HAE for 2, 4, 6, 10, 24, and 72 hours, the functional and morphological alterations of RGCs were assessed using retinal hematoxylin and eosin (H&E) sections, retinal whole mounts, transmission electron microscopy (TEM), and the photopic negative response (PhNR) of the electroretinogram. Results: Compared with the control group, the thickness of the ganglion cell layer and retinal nerve fiber layer increased significantly, RGC loss remained significant, and the amplitudes of a-wave, b-wave, and PhNR were significantly reduced after HAE. In addition, RGCs and their axons exhibited an abnormal ultrastructure after HAE, including nuclear membrane abnormalities, uneven distribution of chromatin in the nucleus, decreased cytoplasmic electron density, widening and vacuolization of the gap between axons, loosening and disorder of myelin sheath structure, widening of the gap between myelin sheath and axon membrane, decreased axoplasmic density, unclear microtubule and nerve fiber structure, and abnormal mitochondrial structure (mostly swollen, with widened membrane gaps and reduced cristae and vacuolization). Conclusions: The study findings confirm that the morphology and function of RGCs are damaged after HAE. These findings lay the foundation for further study of the specific molecular mechanisms of HAR and promote the effective prevention.

To evaluate the efficacy and safety of trabeculectomy, phacotrabeculectomy plus intraocular lens implantation(phacotrab+IOL group) and phacoemulsification with IOL(phaco+IOL) in primary angle-closure glaucoma(PACG). It was a systematic review and meta-analysis, randomized controlled trials(RCT) and clinical controlled trials(CCT) were collected through electronic searches of the Cochrane Library, PubMed, EMbase, Wanfang Database online, Chinese journal Full-text Database, Chinese Scientific Journals Full-text Database (from the date of building the database to October 2010) We also checked the bibliographies of retrieved articles. All the related data that matched our standards were abstracted. The quality of included trials was evaluated according to the Dutch Cochrane Centre. RevMan 5.0 software was used for Meta-analysis. A total of 5 RCT and 11 CCT involving 1495 eyes were included. The results of meta-analysis showed that phacotrab+IOL group was superior than trabeculectomy(trab group) (MD -3.93,95%CI [-7.31, -0.54]) which was also superior than phaco+IOL group(MD 0.52,95%CI [0.10, 0.95]) in decreasing Intraocular Pressure(IOP). Phacotrab group(MD -1.45,95%CI [-1.68, -1.22])and phaco group (MD-1.12,95%CI [-1.87, -0.37])are both deeper than trab group in the anterior chamber depth. In increasing the coefficient of outflow facility of aqueous humor(C values) there was no statistical difference in the three groups. And there was no statistical difference between phacotrab groups and phaco groups in visual acuity but phacotrab group was superior than phaco group (MD 1.07, 95%CI [0.73, 1.40])in the use of IOP-lowering drugs. There was no statistical difference among three groups. Current evidence suggests that phacotrab+ IOL group was superior than trab group which was also superior than phaco+IOL group in decreasing IOP. Phacotrab group and phaco group are both deeper than trab group in the anterior chamber depth. Phacotrab group was superior than phaco group in the use of IOP-lowering drugs.