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The crystalline lens lens thickness playing an essential role in maintaining normal visual function, but little attention is paid to the lens thickness. The purpose of this study is to document the normative values of lens thickness (LT) in healthy subjects of Southern China and to evaluate its associated factors. This was a prospective, clinic-based, observational, cross-sectional study. A total of 526 eyes from 263 healthy subjects aged between 5-84 years (mean age, 38.48 ± 22.04 years) were included in the study. All subjects underwent detailed ophthalmic examination, including the measurement of ocular biometric parameters by LenStar LS900. The study focused on LT and its association with general and ocular factors. The generalized estimation equation (GEE) model was used for statistical analysis. The Mean LT was 4.01 ± 0.57 mm(95% CI, 3.97 - 4.06; median, 3.94 mm; range, 3.10 - 5.36). In a univariate regression analysis, the LT was associated significantly age, body weight, body height, body mass index (BMI), systolic pressure, diastolic pressure, spherical equivalent (SE), intraocular pressure (IOP), anterior chamber depth (ACD) and axial length (AL) (all PPPP

In recent years, composite insulators have been widely applied in transmission lines; however, deterioration of insulation properties caused by aging may cause power supply’s large-scale outage and badly impact the social economy development. Therefore, in this paper, an entirely new method for evaluating aging properties of silicon rubber for composite insulators based on microscopic images was proposed. The microscopic images were collected by portable digital microscope-B011, and defective area proportion (k) was extracted by calculating and comparing the defective area pixel with the background pixel. Thus, the salt fog flashover experiments were conducted in a multifunction artificial climate chamber to indicate aging properties of silicon rubber material; then, the equations for calculating silicone rubber flashover voltage (U50) by k were established. The value of U50 can even decrease by 57.3% with the increase in the value of ${k}$ . Moreover, a complete aging evaluation procedure of silicone rubber composite insulators was obtained. Taking a city as an example, the critical failure ${k}$ ( $k1=19.6$ ) value of composite insulators in the area was obtained. Finally, the future research directions of this paper were clarified; besides, future usage scenarios of this paper were clearly displayed.

Objectives To evaluate the foveal avascular zone (FAZ) area in healthy volunteers using optical coherence tomography angiography (OCTA) and identify factors that influence the FAZ. Methods This single-center cross-sectional study included 526 eyes of 263 healthy volunteers who underwent macular scanning by Zeiss OCTA. A linear mixed model was used to investigate the effects of systemic factors (age, sex, blood pressure, height, and weight) and ocular factors (intraocular pressure, biometric parameters, and central macular thickness) on FAZ. Results In total, 520 eyes of 262 healthy volunteers were included in the analysis. The mean volunteer age was 38.59 ± 22.03 years (range, 5–84 years); 124 volunteers were male (47.33%) and 138 volunteers were female (52.67%). The mean FAZ area was 0.30 ± 0.03 mm2 (95% confidence interval [CI], 0.29–0.31 mm2). Univariate analysis showed that FAZ area was associated with age (β = 0.0011), anterior chamber depth (β = −0.0513), and axial length (β = −0.0202). Multivariate analysis showed that FAZ area was negatively correlated with axial length (β = −0.0181). Conclusions The mean FAZ area in healthy volunteers, measured using Zeiss OCTA, was 0.30 ± 0.03 mm2. Furthermore, FAZ area was negatively associated with axial length; this relationship should be considered in clinical practice.

Pollution-induced flashover is critically affecting the safety operation of the power system so as to puts social production at risk. However, few literatures have predicted insulator pollution levels. Therefore, in this paper grey theory is introduced and GM (1, N) method for the prediction of pollution on insulator surface was proposed. Further, a pollution test lasting for 9 months was conducted to build the GM (1, N) model. The test of another 4 months was also conducted to contrast the test results (ΔESDD (Equivalent salt deposit density)) and predicted results. The research results have shown that: GM (1, N) was applicable to predict the pollution on insulators at the cases of poor information with less data for building model. Besides, considering more environmental factors is conducive to improving the prediction accuracy of the GM (1, N) model. However, wind speed that varied very little during the 13 months' nature contamination periods in Chongqing can be neglected, which may improve the accuracy of the model (with its relative error decreasing from 7.9% to 6.3%). Next, the application scenario of the model is proposed. In addition, GM (1, N) method has potential applications in other field, and the prediction accuracy of GM (1, N) model can also be improved by increasing or decreasing the number of influencing variables as well as the number of samples. The proposed GM (1, N) method provides guidance for anti-pollution work in power systems, which promotes the reduction of flashover accidents and maintain social production safety.