Abstract:

Objective To quantitatively assess the retinal vascular fractal dimension and its associations in an elderly population in Beijing. 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 fractal dimension on zone B and zone C in color fundus photographs from 3901 subjects. One eye of each participant was randomly selected. The region from 0.5 to 1 PD away from the disc margin was zone B, and 0.5~2 PD away from the disc margin was zone C. Main Outcome Measures Retinal vascular fractal dimension (RVDf), fractal dimension arteriole (RVDfa), fractal dimension venule (RVDfv). Results In this study, the RVDf, RVDfa and RVDfv of 3901 elderly people was 1.37±0.04, 1.15±0.05 and 1.16±0.05 respectively. The RVDf, RVDfa and RVDfv in different age groups were significantly different (all P<0.001). These parameters gradually decreased with age. There was no significant difference in RVDf between different genders (P=0.83), but RVDfa and RVDfv were significantly different. Men's RVDfv was larger than women's (P<0.001). RVDfa was smaller in men than in women (P=0.03). Multivariate analysis showed that RVDf was significantly associated with hypertension (r=-0.001, P=0.047). RVDfa was significantly associated with BMI (r=-0.001, P<0.0001). RVDfv was significantly associated with BMI (r=0.0008, P=0.001) and drinking habit (r= 0.0025, P=0.028). Conclusion Retinal vascular fractal dimension gradually decreased with age in elderly population in Beijing. The density of retinal vessels decreased with age as well. Men's RVDfv was larger than women's, but RVDfa was a little smaller in men than in women. (Ophthalmol CHN, 2018, 27: 372-376)

Key words:  retinal vessels, morphology, fractal dimension