ABSTRACT
Objective To observe the changes of blood flow density in the macular area of normal eyes,and to analyze its correlation with age.Methods A cross-sectional study.Two hundred and fifty normal healthy subjects (125 males and 125 females,aged 44.76± 14.77) in routine ophthalmologic examination at the Department of Ophtalmology of Guangdong Provincial People's Hospital during June 2017 to June 2018 were enrolled.Among them,20 to 29,30 to 39,40 to 49,50 to 59,and ≥ 60 years old were 50 subjects (50 eyes) in each.BCVA,slit lamp microscope,indirect ophthalmoscope,OCT angiography (OCTA) examinations were conducted for all eyes.The subjects were examined by both eyes,and the data of 1 eye was selected by EXCEL to generate random numbers,including 126 right eyes and 124 left eyes.The range of 6 mm × 6 mm in the macular area was scanned using a frequency domain OCTA instrument.The software automatically divides it into three concentric circles centered on the macular fovea,which were foveal area with a diameter of 1 mm,parafoveal area of 1 to 3 mm,and foveal peripheral area of 3 to 6 mm.The blood flow density of superficial capillary vessel,deep capillary vessel and foveal avascular area (FAZ) within a 300 μm width (FD-300),FAZ area,perimeter (PERIM),non-circularity index,center retinal thickness (CRT) were measured.The relationship between the blood flow density in macula,CRT,FAZ and age was analyzed by Pearson correlation analysis.Results The mean blood flow density of superficial capillary vessel and deep capillary vessel were (51.61 ± 2.54)％ and (54.04± 5.46)％,respectively.The average FD-300,CRT,PERIM and non-circularity index were (285.55 ± 12.13) μm,(2.150 ± 0.367) mm,1.10 ± 0.04,respectively.The relevance of the results showed that the age was negatively correlated with the blood flow density of whole area (r=-0.335,-0.279;P＜0.01),parafoveal area (r=-0.255,-0.368;P＜0.01),foveal peripheral area (r=-0.330,-0.269;P＜0.01) in superficial capillary vessel and deep capillary vessel as well as FD-300 (r=-0.311,P＜0.01),but not correlated with the blood flow density of foveal area (r=-0.071,-0.118;P=0.264,0.064).There was no relationship between the age and the FAZ area,PERIM,non-circularity index (r=-0.070,-0.055,0.074;P=-0.267,0.385,0.142).The age was negatively correlated with the average CRT (r=-0.217,P＜0.01),but not correlated with the CRT in foveal area (r=0.115,P=0.068).The CRT was positively correlated with the blood flow density of superficial capillary vessel and deep capillary vessel in foveal area (r=0.715,0.653;P＜0.01),but negatively correlated with the FAZ area (r=-0.669,P＜0.01).Conclusion The capillary blood flow density ofmacular area in the normal eyes decreases with age.
ABSTRACT
In recent years, there has been an apparent increase in the occurrence of harmful algal blooms in fresh waters. The value of applying the novel wattle extract (Acacia mimosa) to inhibit algal growth was assessed. Our results showed that the growth of Microcystis aeruginosa was successfully repressed by the plant extract and resulted in decreased extracellular microcystin-LR production. In the experiments, it showed a very effective inhibition in the stage of exponential growth (the largest decrease in level is 47.3% of the control) especially in nonsterile conditions, and the extract can reduce 14.5-24.7% cell density of the control in the stationary stage. In outdoor experiments, the extract reduced dissolved oxygen and pH, and selectively cut down cyanobacterial cell density to one-third of the control after 36 d of treatment. Accordingly, due to competitive inhibition in interspecies, other nanoalgae and small-sized aquatic animals declined, while macrozooplankton increased. Finally, more large algae were eliminated and thereby the water treated was clarified and the recovery of the freshwater ecosystem was promoted. Hence, the present study suggested a new and more effective and very low ecological risk approach to reduce nuisance blooms cyanobacteria in eutrophic water.