Objective: The purpose of this study was to investigate the correlation of vasculogenic mimicry in the primary and recurrent pterygium. Methods: Platelet endothelial cell adhesion molecule-1/periodic acid-schiff (CD31/PAS)immunohistochemical double staining method was adopted to detect the expression of VM in 139 cases of pterygium (105 cases of primary pterygium and 34 cases of recurrent pterygium)and 10 cases of normal conjunctival tissues. The correlation between VM and primary pterygium, recurrent pterygium and the factors such as gender and age of patients were analyzed. Human pterygium fibroblasts (HPFs) were primary cultured and identified by immunocytochemical staining. The differences in the number of VM channels between primary HPFs and recurrent HPFs were observed by three-dimensional culture and PAS staining. Results: There was no VM structure in 10 normal conjunctiva and the positive rate of VM was 43.81% in primary pterygium and 82.35% in recurrent pterygium with a significantly difference (P<0.001). Correlation analysis showed a significant positive correlation between VM and recurrent pterygium (r=0.332). There was no significant difference in the expression of VM in pterygium patients with different sex, age and course (all P>0.05). Vimentin was positive in the primary cultured cells, which was consistent with the characteristics of fibroblasts. The results of three-dimensional culture and PAS staining indicated that HPFs had the ability to construct VM model in vitro, and the number of VM channels constituted by recurrent HPFs was significantly higher than that by primary HPFs, the difference was statistically significant (P<0.01). Conclusion: VM exists in pterygium tissues, and it can be used as one of the blood supply routes, which is closely related to the recurrence of pterygium.

Background: The usage of the light emitting diode (LED) has been increasingly applied in the illumination setting and electronic equipment. However, the effect of LED lights on the retina remains unclear. In this study, we observed and analyzed the impact of white LED lights at different intensities on the function and morphology of rat retinas.

Methods: Thirty-six Sprague-Dawley rats weighing 150–180 g were randomly divided into six groups (n=6 in each group) including a normal control (NC) group, 4 white LED groups at different light intensities (4,000, 6,000, 7,000, and 10,000 lux), and an ultraviolet B (UVB) lighting group (302 nm, 1,000 μw/cm²). After 24 hours of continuous illumination, full-field flash electroretinogram (FERG) and pathological examination were performed in each group.

Results: As revealed by FERG, the impairment of retinal function gradually worsened with the increase of LED light intensity. In contrast, the UVB group had the most severe retinal function impairment. Particularly, the functional damage of rod cells and inner nuclear layer cells was the main FERG finding in each group. In the NC group, the retina had typical morphologies featured by well-defined structures, clearly visible border between the inner and outer segments, and neatly arranged inner and outer nuclear layer cells. After 24 hours of illumination, the inner and outer parts of the retina in the 4,000 lux group were still neatly arranged, along with a clear border; however, the inner and outer nuclear layers were randomly arranged, and some irregular nuclei and cells were lost. The damage of the internal and external retinal segments and the internal and external nuclear layers became more evident in the 6,000 lux group, 7,000 lux group, and 10,000 lux group. The UVB group had a more obviously disordered arrangement of inner and outer nuclear layers and loss of cells.

Conclusions: Continuous exposure to white LED light can cause structural and functional damage to rat retinas, and such damage is related to the intensity of illumination. Therefore, the risk of retinal damage should be considered during LED illumination, and proper LED illumination intensity may help to maintain eye health.