Department of Ophthalmology, Odense University Hospital, Odense, Denmark.
Ophthalmology. 2010 Jul;117(7):1400-5. doi: 10.1016/j.ophtha.2009.10.047. Epub 2010 Feb 21.
Fractal analysis is a method to quantify the geometric pattern and complexity of the retinal vessels. This study examined the association of retinal fractal dimension (D(f)) and microvascular and macrovascular complications in a population-based cohort of Danish patients with type 1 diabetes.
Cross-sectional study.
This was a cross-sectional study of 208 long-term surviving type 1 diabetes patients from a population-based Danish cohort identified in 1973.
Retinal photographs were obtained at a clinical examination in 2007 or 2008. D(f) was measured with a semiautomatic computer-based program (International Retinal Imaging Software; National University of Singapore, Republic of Singapore; University of Sydney, Sydney, and University of Melbourne, Melbourne, Australia). D(f) of the retinal vasculature was measured within a predefined circular region of 3.5 optic disc radii centered on the optic disc. Line tracing of the vasculature was provided by the program. Any artifacts were removed by the grader, and the box-counting method then was used by the program to calculate D(f).
The association of D(f) with proliferative retinopathy, nephropathy, neuropathy, and macrovascular disease (coronary heart disease, stroke, peripheral artery disease) was examined.
Retinal fractals were gradable in at least 1 eye in 178 (86.6%) of 208 patients. Median age and duration of diabetes for these patients were 57.8 years and 42 years, respectively. Median D(f) was 1.4610 (range, 1.3774-1.5188). After adjustments for age, gender, duration of diabetes, systolic blood pressure, and smoking, persons with lower D(f) were more likely to have proliferative retinopathy (odds ratio [OR], 1.45 per standard deviation [SD] decrease in D(f); 95% confidence interval [CI], 1.04-2.03) and neuropathy (OR, 1.42 per SD decrease in D(f); 95% CI, 1.01-2.01). There was also a trend of an association between lower D(f) and nephropathy (OR, 1.39 per SD decrease in D(f); 95% CI, 0.97-2.01) but not macrovascular disease. Furthermore, persons with lower D(f) were older.
This study adds to the evidence that D(f) may have some role as a global measure of retinal vasculature and its association with systemic disease. Prospective studies clarifying this role are needed.
FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.
分形分析是一种量化视网膜血管的几何形态和复杂性的方法。本研究旨在探讨丹麦 1 型糖尿病患者人群中视网膜分形维数（D(f)）与微血管和大血管并发症之间的相关性。
横断面研究。
本研究为丹麦人群中 208 例长期存活的 1 型糖尿病患者的横断面研究，这些患者于 1973 年在一项人群队列中确定。
在 2007 年或 2008 年的临床检查中获取视网膜照片。使用半自动基于计算机的程序（新加坡国立大学的国际视网膜成像软件；新加坡；悉尼大学，悉尼和墨尔本大学，墨尔本，澳大利亚）测量 D(f)。在以视盘为中心的 3.5 个视盘半径的预设圆形区域内测量视网膜血管的 D(f)。血管的线追踪由程序提供。由评分者去除任何伪影，然后程序使用盒子计数法计算 D(f)。
D(f)与增殖性视网膜病变、肾病、神经病和大血管疾病（冠心病、中风、外周动脉疾病）的相关性。
在 208 例患者中，至少有 1 只眼的视网膜分形是可分级的（178 例，86.6%）。这些患者的中位年龄和糖尿病病程分别为 57.8 岁和 42 年。中位 D(f)为 1.4610（范围，1.3774-1.5188）。在校正年龄、性别、糖尿病病程、收缩压和吸烟后，D(f)降低者更可能患有增殖性视网膜病变（优势比[OR]，D(f)每标准偏差[SD]降低 1.45；95%置信区间[CI]，1.04-2.03）和神经病（OR，D(f)每 SD 降低 1.42；95% CI，1.01-2.01）。D(f)降低与肾病（OR，D(f)每 SD 降低 1.39；95% CI，0.97-2.01）之间也存在关联的趋势，但与大血管疾病无关。此外，D(f)降低者年龄更大。
本研究进一步证明，D(f)可能作为视网膜血管及其与全身疾病的相关性的整体测量指标具有一定作用。需要前瞻性研究来阐明这一作用。
作者没有与本文讨论的材料有关的专有或商业利益。
