Pedersen Knud B, Broe Rebecca, Grauslund Jakob
a Research Unit of Ophthalmology , Institute of Clinical Research, University of Southern Denmark , Odense , Denmark.
b Department of Ophthalmology , Odense University Hospital , Odense , Denmark.
Ophthalmic Epidemiol. 2016;23(2):131-5. doi: 10.3109/09286586.2016.1145241. Epub 2016 Mar 7.
To investigate inter-eye agreement in retinal vascular fractal dimension (FD) in patients with type 1 diabetes.
In a cross-sectional study, both eyes were exained in 178 patients with type 1 diabetes. All vessels in a zone 0.5-2.0 disc diameters from the optic disc were traced and FD calculated with the box-counting method using SIVA-Fractal semiautomatic software. The modified Early Treatment Diabetic Retinopathy Study (ETDRS) scale was used to grade diabetic retinopathy (DR). Pitman's test of difference in variance was used to calculated inter-eye agreement in FD according to level of DR.
Mean age and duration of diabetes was 37.0 years and 29.5 years, respectively, and 49.4% of participants were male. Mean FD of right and left eyes was 1.4540 and 1.4472, respectively. FD did not differ between eyes in patients with no or non-proliferative DR (NPDR) in both eyes. This was true for patients with the same level of DR in both eyes (n = 74, p = 0.73), as well as for patients in which the ETDRS level of DR between the eyes differed by 1 (n = 43, p = 0.99) or more (n = 9, p = 0.53). In patients treated for proliferative DR in one eye, FD was significantly lower in this eye compared to the other (n = 10, p = 0.03).
FD did not differ significantly between the two eyes of patients with no DR or NPDR, despite differences in severity of DR.
研究1型糖尿病患者双眼视网膜血管分形维数（FD）的一致性。
在一项横断面研究中，对178例1型糖尿病患者的双眼进行检查。追踪距视盘0.5 - 2.0视盘直径区域内的所有血管，并使用SIVA - Fractal半自动软件通过盒计数法计算FD。采用改良的糖尿病视网膜病变早期治疗研究（ETDRS）量表对糖尿病视网膜病变（DR）进行分级。根据DR水平，使用皮特曼方差差异检验计算双眼FD的一致性。
患者的平均年龄和糖尿病病程分别为37.0岁和29.5年，49.4%的参与者为男性。右眼和左眼的平均FD分别为1.4540和1.4472。双眼无DR或非增殖性DR（NPDR）的患者，其双眼FD无差异。双眼DR水平相同的患者（n = 74，p = 0.73）以及双眼ETDRS DR水平相差1级（n = 43，p = 0.99）或更多（n = 9，p = 0.53）的患者均如此。一只眼接受增殖性DR治疗的患者，该眼的FD显著低于另一只眼（n = 10，p = 0.03）。
无DR或NPDR的患者双眼FD无显著差异，尽管DR严重程度存在差异。
