COVID-19 pandemic impact on ocular trauma in a tertiary hospital.

AIM: To analyze the impact of the coronavirus disease-2019 (COVID-19) pandemic on the presentation and characteristics of patients hospitalized for ocular trauma in a tertiary hospital in China between 2019 and 2020. METHODS: A retrospective case study was designed to collect information on all cases of ocular trauma in a tertiary hospital from 2019 to 2020 and compare differences in inpatients' data (age, sex, admission vision acuity, type of diagnosis, hospital stays, mechanism of injury and location of injury). RESULTS: The total number of patients admitted to the Ophthalmology Department was 883 (mean 73.58±11.25 patients per month) in 2019 and 714 (59.50±17.92 patients per month) in 2020. The injury number of in work was also the most within the four types of location in this two year (42.36% in 2019, 43.84% in 2020). The mean hospital stays were 12.66d in 2019 and 10.81d in 2020. The highest incidence of ocular trauma was the middle-aged (41-65y) groups in 2019 and 2020. The most common cause of ocular trauma was sharp object in 2019 (47.34%) and 2020 (47.58%). The mechanical ocular trauma reaches 98.98% in 2019 and 99.72% in 2020. CONCLUSION: The number of patients with ocular trauma decreased in 2020, but middle-aged (41-65y) are still high incident groups. Mechanical ocular trauma remains the leading cause of hospitalization for ocular trauma patients and the proportion of patients injured at home increases. It is necessary to arouse social attention and the public's awareness of eye trauma protection should be strengthened during the pandemic.

Experimental Study of the Biological Properties of Human Embryonic Stem Cell-Derived Retinal Progenitor Cells.

Retinal degenerative diseases are among the leading causes of blindness worldwide, and cell replacement is considered as a promising therapeutic. However, the resources of seed cells are scarce. To further explore this type of therapy, we adopted a culture system that could harvest a substantial quantity of retinal progenitor cells (RPCs) from human embryonic stem cells (hESCs) within a relatively short period of time. Furthermore, we transplanted these RPCs into the subretinal spaces of Royal College of Surgeons (RCS) rats. We quantified the thickness of the treated rats' outer nuclear layers (ONLs) and explored the visual function via electroretinography (ERG). It was found that the differentiated cells expressed RPC markers and photoreceptor progenitor markers. The transplanted RPCs survived for at least 12 weeks, resulting in beneficial effects on the morphology of the host retina, and led to a significant improvement in the visual function of the treated animals. These therapeutic effects suggest that the hESCs-derived RPCs could delay degeneration of the retina and partially restore visual function.

c-Kit⁺ cells isolated from human fetal retinas represent a new population of retinal progenitor cells.

Definitive surface markers for retinal progenitor cells (RPCs) are still lacking. Therefore, we sorted c-Kit(+) and stage-specific embryonic antigen-4(-) (SSEA4(-)) retinal cells for further biological characterization. RPCs were isolated from human fetal retinas (gestational age of 12-14 weeks). c-Kit(+)/SSEA4(-) RPCs were sorted by fluorescence-activated cell sorting, and their proliferation and differentiation capabilities were evaluated by using immunocytochemistry and flow cytometry. The effectiveness and safety were assessed following injection of c-Kit(+)/SSEA4(-) cells into the subretina of Royal College of Surgeons (RCS) rats. c-Kit(+) cells were found in the inner part of the fetal retina. Sorted c-Kit(+)/SSEA4(-) cells expressed retinal stem cell markers. Our results clearly demonstrate the proliferative potential of these cells. Moreover, c-Kit(+)/SSEA4(-) cells differentiated into retinal cells that expressed markers of photoreceptor cells, ganglion cells and glial cells. These cells survived for at least 3 months after transplantation into the host subretinal space. Teratomas were not observed in the c-Kit(+)/SSEA4(-)-cell group. Thus, c-Kit can be used as a surface marker for RPCs, and c-Kit(+)/SSEA4(-) RPCs exhibit the ability to self-renew and differentiate into retinal cells.