Abstract: Objective To quantitatively describe the population distribution characteristics of retinal vascular tortuosity in elderly population. Design Cross-sectional study. Participants Baseline population of Beijing Eye Study. Methods Quantitative measurement software (Singapore I Vessel Assessment, SIVA 3.0) was used to measure the parameters of retinal vascular tortuosity in color fundus photographs selected from 3901 subjects. One eye of each participant was randomly selected. The study population was divided into 6 groups: 40-44, 45-49, 50-54, 55-59, 60-64 and age of 60+ years. The region from 0.5 to 1 PD away from the disc margin was zone B, 0.5-2 PD away from the disc margin was zone C. Parameters include simple tortuosity arteriole (sTORTa), curvaturetor tuosity arteriole (cTORTa), simple tortuosity venue(sTORTv), curvature tortuosity venule (cTORTv). The distribution of population, age and gender of these indicators was described and the relationship between retinal vascular tortuosity and related factors such as age, gender, BMI and hypertension, diabetes, coronary heart disease, stroke, smoking and drinking from the questionnaire were analyzed with multivariate analysis. Main Outcome Measures sTORTa, cTORTa, sTORTv, cTORTv.  Results The sTORTa and cTORTa of 3901 subjects was 1.087±0.021 and 0.0000291±0.0000071, respectively. The sTORTv and cTORTv was 1.098±0.019 and 0.0000356±0.0000079, respectively. The TORTa in different age groups was significantly different (P=0.000), the indicator gradually decreased with age. Men's cTORTa was smaller than women's (all P=0.034). There was no significant difference in sTORTv between different age groups (P=0.169), but cTORTv was gradually increased with age (P=0.022). There was no difference in sTORTv between different genders (P=0.141). Multivariate analysis showed that sTORTa was associated with age (r=-0.001, P=0.013). cTORTa was associated with age (r=-4.21E-8, P＜0.0001), BMI (r=-5.64E-8, P＜0.0001) and hypertension (r=-8.16E-8, P＜0.0001). sTORTv was associated with BMI (r=0.001, P=0.008). cTORTv was associated with age (r=4.36E-8, P＜0.0001), BMI (r=1.16E-7, P＜0.0001), hypertension (r=1.36E-9, P＜0.0001) and hyperlipemia(r=-8.85E-8, P＜0.0001). Conclusion In population with 40 years or older, retinal arteries tend to straighten with age, while cTORTv was slightly increased with age. Men's cTORTa was smaller than women's. The retinal artery with a straight shape was associated with older age, higher blood pressure and BMI; the curved retinal vein was associated with higher BMI, higher blood pressure and lower levels of blood lipids. (Ophthalmol CHN, 2021, 30: 97-101)

Key words:  retinal vessels, morphology, vascular tortuosity